# Cone area is King - Dual 18s in a Cruze



## tecollins1 (Nov 6, 2011)

AND IT BEGINS!

:bowing:


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## 4piecekit (Mar 17, 2011)

18? Wow. I can only imagine that diameter because one of my floor toms is an 18...dang. I am very curious as to how this build is going to look. Can't wait. Don't tease too much.


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## EcoDave (Mar 7, 2013)




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## XtremeRevolution (Jan 19, 2012)

EcoDave said:


>


LOL!

Keep in mind, I'm going for impact and accuracy at loud volumes, not just raw SPL at one specific test tone. Furthermore, this will actual result in a net gain in trunk space from my current IDQ15 (which is has a very small footprint for such a big sub), a net reduction in weight, and the only compromise will be the inability to have quick and easy access to the pass-through of the trunk. I hope to be able to create a system that allows me to quickly and easily remove the trunk baffle so I can use the pass-through.


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## obermd (Mar 3, 2012)

And here I though you meant Winter was over and Road Cone season had begun. :th_coolio:


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## tecollins1 (Nov 6, 2011)

I guess the other chevy will be the "material haul vehicle" don't think you will be able to get a couple sheets of MDF in your car without cutting them before hand 


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## iKermit (Dec 13, 2010)

Off topic: I read the thread title as "North Kore is King" wtf?

On topic: This will be epic... Update us with more teasers im a ***** for teasers...


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## 1990tsi (Apr 29, 2011)

How are you going to block the rear deck 6x9 holes?

I used 1/4 mdf, 'no nails' wood glue and it's still holding great. (I had plans of IB but never got around to it!)


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## jakkaroo (Feb 12, 2011)

you wanna sell me that 15 with box?


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## XtremeRevolution (Jan 19, 2012)

1990tsi said:


> How are you going to block the rear deck 6x9 holes?
> 
> I used 1/4 mdf, 'no nails' wood glue and it's still holding great. (I had plans of IB but never got around to it!)


1/2" MDF, gasket tape, and sheet metal screws. Makes it easily removable, and I can drill out the holes from the screws to make them look prettier if I ever want to reverse it. For the smaller holes, I have some CLD tiles left that I can use to cover them up, and I may even get some MLV and CCF to cover the deck just for good measure. 

I've been thinking about how to make the whole thing rigid yet easily detachable, and I think I just figured out how. Bike axles with quick-release levers. 

Sunringle Cam Skewer Quick Release > Components > Wheel Goods > Quick Releases | Jenson USA Online Bike Shop

If designed correctly, 6 of those should be enough to hold the baffle in place and allow easy removal when I need to remove them to use the pass through.


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## XtremeRevolution (Jan 19, 2012)

jakkaroo said:


> you wanna sell me that 15 with box?


I have a guy who already called dibs on it, but if that falls through, I'll let you know.


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## jstoner22 (Aug 21, 2012)

I'm excited to see this!

What are you powering these with?
What are the specs on them?
I could have passed right over it, but it sounds like you are going infinite baffle?


Also, I'd hold onto the 15" for now personally. It is a fairly hard sub to find, and until you hear the results of this new endeavour, I wouldn't part with it.

good luck!


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## XtremeRevolution (Jan 19, 2012)

jstoner22 said:


> I'm excited to see this!
> 
> What are you powering these with?
> What are the specs on them?
> ...


Powering either with my Alpine MRP-M1000, or with a pair of Kenwood amps. I may spring for a Boston Acoustics high powered 2ch amp if I don't like the Alpine. I will probably end up selling the Alpine to go Class AB.

Specs are in the link I posted. Super low moving mass, 9.6mm xmax, low Qts. Matt Borgardt approved.

Yep. Infinite Baffle is indeed the intention. 
I love the IDQ15, but I want to head away from boxed subs for a number of reasons. I would have gone IB with two IDQ15s, but in the year I've been searching, I couldn't find one. Worst case, if I hate these (unlikely), I'll replace them with the new 15" IDMax or another SQ sub. I also have two IDQ12 V2 subs sitting in my garage without a home. 

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## XtremeRevolution (Jan 19, 2012)

Sold the Alpine MRP-M1000 amp that I was using with the IDQ15. I needed a Class AB amp, which has an inherently better damping factor than Class-D amps. It's not really an issue with a boxed sub, but it's more important for this type of install. 

The replacement amp?

Boston Acoustics GT-2300. Bridged, this will provide 1000W *@ 4 ohms*, which is the load I'll be giving it with the two subs. The ingenious cooling design allows me to mount it anywhere and in any orientation.










22-1/4" in length, 9" in width, and 2-3/8' in height

Built in Q-adjustment will allow me to effectively tune the subs to simulate a given sealed box volume. 

At nearly 2 feet long, I'm not yet sure where I'll mount it yet...


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## XtremeRevolution (Jan 19, 2012)

By the way, just so people understand why I decided to go with a Class AB amp, there are two primary reasons. 

1. I wanted more power @ 4 ohms. My Alpine MRP-M1000 provided 600W @ 4 ohms, and the Boston Acoustics GT-2300 provides 1000W @ 4 ohms. 
2. Damping factor. See the following link:

www.crownaudio.com/media/pdf/amps/damping_factor.pdf


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## Smurfenstein (Nov 16, 2011)

tecollins1 said:


> AND IT BEGINS!
> 
> :bowing:


With me following close behind 

I mean someone's gotta rep the west coast haha.


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## Smurfenstein (Nov 16, 2011)

XtremeRevolution said:


> Sold the Alpine MRP-M1000 amp that I was using with the IDQ15. I needed a Class AB amp, which has an inherently better damping factor than Class-D amps. It's not really an issue with a boxed sub, but it's more important for this type of install.
> 
> The replacement amp?
> 
> ...


Can the cooling work properly if its enclosed on all sides? If so you might be able to fit it under the trunk floor and simply remove some of the foam. Although i'm pretty sure the foam is only a little over an inch thick, two max. But its an idea. Could work with some tweaks.


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## XtremeRevolution (Jan 19, 2012)

I think that might insulate it too much like a blanket. You at least need to keep the heatsink clear, even though it is internally fan cooled. If anything, I'll put it in the hole in the floor of the Eco's trunk if I want it out of sight.


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## jstoner22 (Aug 21, 2012)

I understand the power, but infinite baffle or not, the relevance of dampening factor is debatable.


Here is an excerpt from a recent write up by Steve Mantz

"Damping Factor - This amplifier specification has been blown out of all proportion. What it means is the ability of the amplifier to resist a change in it’s output voltage. The formula is DF= Speaker Z / Amplifier output Z (where Z is impedance). So many manufacturers have claimed ridiculous, and often false damping factors. A damping factor of 1000 implies that the output impedance of the amplifier is 0.004 ohms (4 ohm load). The only way to attain this figure is to apply masses of negative feedback (or use positive feedback) and too much feedback makes amplifiers sound harsh and clinical. Alsodamping factor changes with frequency. The lower the frequency the higher the DF number. Typically the DF can be ten times larger at higher frequencies.
Let us take this amplifier whose output impedance is 0.004 ohms (Zout). The speaker circuit is a series circuit and the following impedances(resistances) are in series with this 0.004 ohms. Let us assume that this DF measurement was made at the amplifier’s speaker terminal. The first extra contact resistance is the speaker wire to the speaker terminal (WT ohms). Then there is that of the wire itself for two conductors (W). Next is the contact resistance of the wire to the speaker terminal (WS). Next there is the contact resistance of the wire from the speaker terminal to the voice coil (WV) and lastly there is the DC resistance of the voice coil itself (DCR). So what we have is a series circuit with the following resistances in series and adding up. WT+W+WS+WV+DCR+Zout. WT,W,WS,WV and Zout are very small indeed. Certainly less than 0.1 ohms. Whoa, look what has happened the EFFECTIVE DAMPING FACTOR has been reduced from 1000 to
40 by just taking into account those pesky unavoidable contact resistances. Now for the cruncher, remember that the DCR is also in series and is typically 3.2 ohms for a nominal 4 ohm speaker. So we must add 0.1+3.2 = 3.3 ohms and now EFFECTIVE DAMPING FACTOR is now a magnificent 1.212! (4 divided by 3.3)This is the real world. We see that the DCR of the speaker swamps all other resistances in the speaker circuit and the 0.004 ohms amplifier output impedance is almost meaningless. It has been found that a DF of about 20 is quite sufficient to dampen the voltage spikes from the speaker. An eye opener this one is it not? Good tube amps sound marvelous - low damping factors!!"


Here is a link to an article by Richard Clark
http://www.monstercable.com/mpc/stable/tech/A2412_Damping_Factor_Article.pdf


Here is a recent write up from Andy Wehmeyer
"Damping factor is hogwash, pure and simple. There is no appreciable cone control provided by low amplifier output impedance.

Here's the short story. The preposterous arguement for damping caused by amplifiers is based on the idea that the output impedance of the amplifier causes the energy stored in the inductive component of the moving speaker to be dissipated more quickly, because the current flow is greater from the speaker to the amplifier if the amplifier has a lower impedance. The problem with that BS theory is that the speaker's DCR is in series with the amplifier's output impedance and is always MUCH greater than the output impedance of the amplifier. Therefore, the speaker's DCR is what controls damping in the electrical circuit and not the amplifier. "

and his recommended source reading ... http://www.diyspeakers.net/Articles/...G%20FACTOR.pdf

These are just a couple of 'pioneers' in the car audio game. You will not find more reputable sources than these. There are a plethora of people that agree that damping factor is near irrelevant in modern amps (as they all boast a sufficient value...in quality amps anyways)



Regardless, I like the amp choice. Very nice.

I'm sure you have looked into it, but what kind of draw will there be? (seeing as it is a high powered A/B)


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## XtremeRevolution (Jan 19, 2012)

jstoner22 said:


> I understand the power, but infinite baffle or not, the relevance of dampening factor is debatable.
> 
> 
> Here is an excerpt from a recent write up by Steve Mantz
> ...


I hear what you're saying about damping factor, and it's something I hadn't heard of until I spoke to Matt. Matt Borgardt that is. I ran the whole idea by him and one of his recommendations was to get rid of the Alpine Class-D amp and use Class AB amplification instead, for two reasons. The first was damping factor. The claim there was that Class AB amplification would have a better damping factor than Class D amplification. It's something Zapco strongly prides themselves of in their owner's manuals. The second was sound quality. I thought...but it's 2012, not 2002...surely Class D has come much farther since then. Matt mentioned that there's so much noise introduced into the signal path in Class D amplification with nothing more than an inductor on the end of that signal to clean it up, that it's far from the level of Class AB. I'll admit to not being much of an expert in amplifier architecture so I figured I'd take the word of the guy who engineered the IDQ and IDMax. I've often found that you don't necessarily have to be an expert with a complete understanding of what you're talking about in order to be successful and give valid advice; but rather to have been given advice and been trained by an expert. While I've found many sources that claim it's irrelevant as you did, I figured I'd take Matt's advice as I'm certain I wouldn't be led in the wrong direction. 

At the end of the day though, whether or not this amp provides better sound quality or a consequently better damping factor isn't of much consequence as I simply wanted more power. I had 600W @ 4 ohms with the MRP-M1000, and now I'll have 1000W @ 4 ohms. It is far too expensive to get this much power @ 4 ohms with a Class D amp. 

I've always liked the Boston Acoustics amps. Something about them impressed me and I had the sense that I was buying a high end amp for mid range money. the Q-tune adjustment will help quite a lot with the IB install, which is something I have on other BA amps I've owned. My wife uses a GT-50 (5 channel) and I have a GT-40 that I'll be using to replace the Coustic Power Logic amps I'm currently using in the front stage (made in 1992). They're great amps and have served me flawlessly for almost a year (not including the many owner(s) that used them before I got them), but if I can match amplifiers, why not? One thing that has always impressed me is the fact that most if not all Boston Acoustics amps are 1-ohm stable (unbridged), which is rare for a Class AB amp and gives me the impression that it's a quality unit. I'm not sure why the GT-2300 doesn't actually rate 1-ohm output, but one can deduct from the 1400W RMS @ 2 ohm bridged specification that you can get 700W x 2 @ 1 ohm from the amplifier unbridged. I also very much like the fact that they rate 12V output as well as 14.4V CEA-certified output. Boston Acoustics also claims they are underrated. 

To top it all off, the amp was only $200 brand new. Shipped. 

I tried to some research on efficiency, but wasn't really able to get a good idea of how much power I'll be drawing. My best guess is that it won't be a whole lot considering these subs will be likely to bottom out with some high peaks, although a secondary battery might be needed only to allow the system to deal with those peaks. I have one of Terry's "Big 3" wiring upgrades that should help keep voltage oscillations to a minimum.


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## XtremeRevolution (Jan 19, 2012)




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## jstoner22 (Aug 21, 2012)

what have you done for bracing on your rear deck?

I'm having some issues with mine and my sub set-up (flexing/rattling/vibrating). I can only imaging what is going to be required for an infinite baffle set-up.


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## XtremeRevolution (Jan 19, 2012)

jstoner22 said:


> what have you done for bracing on your rear deck?
> 
> I'm having some issues with mine and my sub set-up (flexing/rattling/vibrating). I can only imaging what is going to be required for an infinite baffle set-up.


Going to get more CLD tiles, some MLV, and some CCF to keep it loaded down and free from vibration. 

I just got started. Today involved removing the old sub amp and trunk panels, and making the left part of the baffle frame. It will take me a little while to finish this project.

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## jstoner22 (Aug 21, 2012)

I find the issue isn't with the actual metal, but the upper panelling. There is spacing between the brake light casing and the window. This is a big source of rattling.

whenever you get around to the bracing and deadener treatment be sure to post some details!


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## XtremeRevolution (Jan 19, 2012)

jstoner22 said:


> I find the issue isn't with the actual metal, but the upper panelling. There is spacing between the brake light casing and the window. This is a big source of rattling.
> 
> whenever you get around to the bracing and deadener treatment be sure to post some details!


Aaaah. That. That can be resolved with some CCF. 

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## XtremeRevolution (Jan 19, 2012)

Amp came in on Wednesday. The thing is HUGE, and heavy too. Four 4-gauge power terminals (two for positive and two for negative). I'll try to get some pictures next to the subs tomorrow as I'll be out working on the car again.


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## hificruzer226 (Mar 27, 2013)

XTREME is correct cone area is king! dual 18 IB AWESOME!!! a little overkill but it will be awesome, I love free air because you hear the bass not the box. If i had the balls I would be right there with ya. I just want to keep the current down powering those bad boys up will be a nice drain (assuming you are not adding/replacing alternator(s) and adding batteries. BTW what is our stock alt rated?


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## XtremeRevolution (Jan 19, 2012)

hificruzer226 said:


> XTREME is correct cone area is king! dual 18 IB AWESOME!!! a little overkill but it will be awesome, I love free air because you hear the bass not the box. If i had the balls I would be right there with ya. I just want to keep the current down powering those bad boys up will be a nice drain (assuming you are not adding/replacing alternator(s) and adding batteries. BTW what is our stock alt rated?


Haha, I'm glad you're enjoying this project. Dual 18s will indeed be awesome. There's a good chance you'll be able to hear them at Lordstown, and yes, I agree, you can hear the bass, not the box, and not the trunk's boundary loading. Much better dynamics, much tighter bass, and an overall much better sound from an SQ perspective. I started out with the power concerns you're expressing, but here are a few things to consider:



I'm not a _huge _bass head. I'll go up to a certain level, but there's only so much I can stand for extended periods. My front stage has to be able to keep up if I'm going to enjoy it. I stop enjoying music when all I hear is bass. The reason I went with two 18s instead of two 15s is because the price difference was within $30. I figure, 60% more cone area for only $30? That's a deal I'm willing to make. The more cone area I can get, the greater my kick drum impacts will be, and the great my efficiency will be.
I don't often listen to music with heavy synthetic bass such as rap or dubstep. My biggest issue will be sharp voltage drops from big peaks and dynamics, not from sustaining a 35-40hz note for extended periods of time. My lights will dim due to the sharp power demands, but I won't be killing my primary battery over it.
I'll be wiring them down to 4 ohm, since they're 8 ohm sub. I should have better or equal efficiency at 4 ohm with this class AB amp than others are having at 1 ohm with a class D amp.
Efficiency. Both of these will produce 100.7db (not including cabin pressurization and boundary loading) at *one watt*! Furthermore, these have only 9.6mm of xmax, and I'll be running them in free air, which means that they will produce their maximum SPL with far less power than if they were boxed. No air suspension means easy excursion. Their incredibly high efficiency and IB application should require far less power than, say, a single 15" in a ported box would to achieve the same volume.
I will be upgrading the Big 3 wiring (already bought the kit from Terry) to assist with electrical load.

I do not plan on doing anything to the electrical system past that point, although if the peaks cause enough of a voltage drop each time a kick drum slams, I will probably invest in a small audio battery to keep that from happening. I initially bought the IDQ15 because of its high efficiency and very high output per watt used, which meant my electrical system rarely ever experienced any significant load. Our stock alternators are rated for 140 amps. Not bad for an econobox. A battery is all I will need given how loud these will get per watt of power.


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## Mick (Dec 31, 2011)

Moar pics!!

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## XtremeRevolution (Jan 19, 2012)

Mick said:


> Moar pics!!
> 
> Sent from AutoGuide.com Free App


Coming later today!

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## XtremeRevolution (Jan 19, 2012)

Alright, some photos for perspective. The big one is the Peavey 18". The smaller sub is an Image Dynamics 12" IDQ12 V2. The amp is the Boston Acoustics gt-2300 that just came in.


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## Gravity (Apr 6, 2013)

XR why dont you just get like 20 of those and turn your cruze into a hover craft :th_coolio:


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## Smurfenstein (Nov 16, 2011)

I'm going to keep slowly ordering parts for my build before I post a thread. Cant wait to see your baffle done so I can have a better picture to drool over while mine is waiting on the funds to be made/installed.


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## XtremeRevolution (Jan 19, 2012)

Smurfenstein said:


> I'm going to keep slowly ordering parts for my build before I post a thread. Cant wait to see your baffle done so I can have a better picture to drool over while mine is waiting on the funds to be made/installed.


I hope you at least ordered the amp. Being disconued, and considering that Boston Acoustics will no longer be making amplifiers, you better buy one before they sell out.

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## Mick (Dec 31, 2011)

What's all that going to do to your mpgs lol

can't wait for the video


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## XtremeRevolution (Jan 19, 2012)

Mick said:


> What's all that going to do to your mpgs lol
> 
> can't wait for the video


Well, the subs are 22 pounds each and I'm putting about 20 pounds of wood and hardware in there. Add another 13 pounds for the amp, which brings it to a total of 77 pounds. However, I'm replacing the two old Coustic amps with a newer Boston Acoustics GT-40, which will save me about 5 pounds. 

I just tried to ship my IDQ15 + Alpine amp via post office and they wouldn't take it because they said it was over 70 pounds, so I have to send it via FedEx. From what I had before, I'd say my fuel economy will remain the same.


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## Smurfenstein (Nov 16, 2011)

XtremeRevolution said:


> I hope you at least ordered the amp. Being disconued, and considering that Boston Acoustics will no longer be making amplifiers, you better buy one before they sell out.
> 
> Sent from AutoGuide.com App


The sub amp arrived in the mail today, tomorrow will be the test fit to see if I can swap my Brutus with it. If so the Brutus will be for sale here on the forums, and once I get the cash the little amp will be ordered.


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## Blue Angel (Feb 18, 2011)

Nice project, XR! With over 100 db/w you could probably get away with one of those cheap little Class D Sure amps hooked to 12v running 10-15W/sub. That would put you solidly into 120 db territory given the reality of cabin gain. That boston amp idling out ~100W will have you turning it down to preserve your hearing!

Is this the sub you're using?
Peavey 18" Low Max Subwoofer Speaker Driver 294-3100


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Nice project, XR! With over 100 db/w you could probably get away with one of those cheap little Class D Sure amps hooked to 12v running 10-15W/sub. That would put you solidly into 120 db territory given the reality of cabin gain. That boston amp idling out ~100W will have you turning it down to preserve your hearing!
> 
> Is this the sub you're using?
> Peavey 18" Low Max Subwoofer Speaker Driver 294-3100


Indeed, it will be a VERY high efficiency design. It will weigh about the same as my last setup, but will produce much higher output with much less power. 

That isn't the sub. That's the Low Max. I'm using the Low Rider. Slightly lower excursion, for a much lower cost. 

I got some pictures of my progress today. I am hoping to fire up the system on Wednesday night. It won't be carpeted and it will look like solid wood, so I'll take it apart next week again to carpet it all and make it look more professional. I have the anchor points and frame construction all figured out so it's only a matter of time now. 

Right side is anchored in









1/2" bolts require a 1/2" hole...

















Left side is anchored in. The sides will also be anchored at the top. I just didn't have time to drill the holes today. 









For anyone looking to do this in the future, the anchor points are 4" from the bottom. 

On the outside, I'm using two neoprene rubber washers to keep water from getting in. Note: I will modify a metal washer to place over them when I take it apart, but I had to get this together quickly as I had somewhere to go today. 

















Test fitting the bottom frame









Not much longer now...


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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> That isn't the sub. That's the Low Max. I'm using the Low Rider. Slightly lower excursion, for a much lower cost.


Ah, yes, I missed that one. So why would you ever recommend the 15" version in your sub thread when an 18" exists for ~$40 more?  Mo is always betta!



XtremeRevolution said:


> 1/2" bolts require a 1/2" hole...


Folks, he is "The ONE"


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## Smurfenstein (Nov 16, 2011)

Blue Angel said:


> Ah, yes, I missed that one. So why would you ever recommend the 15" version in your sub thread when an 18" exists for ~$40 more?  Mo is always betta!


Because it all depends on your wants/needs, and ultimately, your budget. Besides, very few people will try and fit/squeeze an 18" into their Cruze. I am one of those crazy ones that is doing a very similar dual 18 baffle set up to XR, but then again I'm 19, naive, stupid, and just plain crazy. I have a 1.8, so If I cant leave your car in the dust, I'll turn it to dust with my audio system haha.


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## Blue Angel (Feb 18, 2011)

Smurfenstein said:


> ...I'm 19, naive, stupid, and just plain crazy.


...and have a great sense of humor! LOL!

I might date myself by saying "been there done that", but trust me when I say there's still a crazy 19 year old in me that wishes a pair of 18's were on their way into the trunk of my car. 

And for the record, my comment to XR was a little sarcastic... the 15 would suit most people just fine I'm sure!


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## Smurfenstein (Nov 16, 2011)

Blue Angel said:


> ...and have a great sense of humor! LOL!
> 
> I might date myself by saying "been there done that", but trust me when I say there's still a crazy 19 year old in me that wishes a pair of 18's were on their way into the trunk of my car.
> 
> And for the record, my comment to XR was a little sarcastic... the 15 would suit most people just fine I'm sure!


The two 10s I have in my trunk atm would suit most people, 15s would suit few who want more, and 18s... 18s are for people like me and Andrei haha.


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Ah, yes, I missed that one. So why would you ever recommend the 15" version in your sub thread when an 18" exists for ~$40 more?  Mo is always betta!
> 
> 
> 
> Folks, he is "The ONE"





Blue Angel said:


> ...and have a great sense of humor! LOL!
> 
> I might date myself by saying "been there done that", but trust me when I say there's still a crazy 19 year old in me that wishes a pair of 18's were on their way into the trunk of my car.
> 
> And for the record, my comment to XR was a little sarcastic... the 15 would suit most people just fine I'm sure!


It actually has more to do with practicality and application. Not that an 18" sub is practical by any means... I chose the 18s for this build simply because I could, and the price difference was only $30 over the 15". In an IB install, you can go as big as you want because you won't end up paying for it in box size. So long as you have the vertical trunk height, you could go as big as your dimensions allow. Also, there is no need for a box, as the trunk is your box. 

If you did not intend on drilling 1/2" holes into your trunk to anchor a wooden frame to support an IB install, then you wouldn't be able to fit the 18" sub in your trunk. The 15" requires just over 2 cubic feet of space, and the 18" would be closer to 4 cubic feet and would need a box that is no shorter than 19" tall. It's just impractical, and the box height would likely not fit through the trunk opening because it's too large. You'd have no way to get it in there. The trunk opening allows a box up to 17" tall and 31" wide to fit.


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## XtremeRevolution (Jan 19, 2012)

Looks like I may just be able to hear these soon, albeit with inadequate sealing. I won't have time to seal off the rear deck or cover up the holes to the left and right of my side braces. 

Bottom frame is bolted in. 

















Had to trim the metal shield a bit to get the bolts to screw in nicely, but that wasn't too bad. I used two neoprene rubber washers here as well, for each bolt, as well as a metal washer to evenly apply pressure. I may have to replace those washers 10 years from now, but they'll hold up nicely. I lost the pictures I had of the other side, but it's basically the same thing. 









Top frame needed to be smoothed a bit as the sheet metal curves upward. 









My first mistake was to drill the bolt holes too close to the edge. I had to re-drill them in the center. Visually unappealing, but it will work just fine. I used a router bit to flush out enough depth for a bolt to sit flush inside the frame, so I wouldn't need to do the same on the baffle. 

















A socket fits, so it will be easy to tighten. 









We're in business!









Test fit first panel: Looks good! Top left and right corners are touching though...









Here's where the corners are touching. Notice how the sheet metal curves forward.

















Dual bevel sliding miter saw!

























That's better...

















Time to make the baffle. This was a pain in the you-know-what. Peavy listed cutout spec as 16-3/8". The spec I found on other forums is 16-3/4". However, both of those were wrong. The actual cutout spec is 16-11/16". For the baffle, I used two layers of 3/4" Home Depot baltic birch plywood, with a 1/2" layer of MDF sandwiched in the middle. I added the MDF to give it some more heft and to provide more material for the subs to screw into. The panels don't line up 100% perfectly on the edges, but a flush trim bit on my router will fix that in no time. I used every last one of my clamps on this.


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## hificruzer226 (Mar 27, 2013)

XtremeRevolution said:


> Looks like I may just be able to hear these soon, albeit with inadequate sealing. I won't have time to seal off the rear deck or cover up the holes to the left and right of my side braces.
> 
> Bottom frame is bolted in.
> 
> ...


we need more cowbell ...i mean clamps


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## Blue Angel (Feb 18, 2011)

Looks like one heckuva rear strut brace.


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Looks like one heckuva rear strut brace.


Which reminds me. Fair warning to anyone reading this who wants to do the same thing: don't install the top brace while the car is lifted on one side. I lifted the driver's side of the car so I could attach the side braces, which created enough body flex to throw off where I drilled the holes for the top brace when I dropped the car back down. Either keep it in the air, keep it on the ground, or lift both sides equally.


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## Mick (Dec 31, 2011)

It's about to get real...

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## Smurfenstein (Nov 16, 2011)

Ohhh man, I need to stop looking at this thread or else I'm going to kill myself waiting until I get everything ready for Matt to build mine D:


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## XtremeRevolution (Jan 19, 2012)

Stayed up till 2:15AM last night finishing this thing. Took a lot longer than I had expected...

Yesterday, I finished gluing the baffle together. Will it fit? That's what she said...

















My phone was dead, so I didn't get a chance to show some of the baffle work I did, but I drilled out 1/4" holes for the sub bolts, which are pan head stainless. I'm using 1/4" T-nuts to hold the subs in. 

To mount the baffle to the frame, I also used 1/4" pan head stainless bolts. I used wood screw inserts (forgot what they're called). You drill a larger hole and screw these in with an allen wrench.









I had to counter-sink the screws 3/4" because I didn't initially plan on using a 2" thick baffle (originally planned on 1.5"), and the bolts I bought were only 2". Store was closed by this time. I'll probably end up buying some 3" screws later and using washers later. Not sure yet. The whole setup is getting pulled to be carpeted next week. I did get the baffle mounted though, and **** is it strong. It will definitely add some structural rigidity to the rear of the car, lol.









Subs are mounted! It's a tight fit from behind (lol), but it works! You may notice that 4 bolts are missing (the ones closer to the center of the baffle). That's because Home Depot only had 12 t-nuts, and I needed 16, so I just bought what I could. I'll visit another home depot to buy the other 4 later. 

































I went out just now and snagged a couple of pictures from the back. They have maybe 1/2" of clearance to the backs of the seats. Talk about space savings! As an added bonus, it looks like my amps are going to fit behind the seats too.









Here, you can see the t-nuts I used. 









Amps are getting hooked up later today before we leave on our trip. It's not going to be pretty as I just need them to work. Probably going to just mount them to a piece of MDF or plywood to hold them in place.


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## coinneach (Apr 10, 2012)

...I think I just got religion. :bowing:

Andrei, if a miracle happens between now and the meet, I'm gonna hire you to build me an absolute ball-buster of a system.


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## Blue Angel (Feb 18, 2011)

Andrei, are you planning to "vent" the rear seat backs at all? I haven't taken the carpet off to look at what's behind it, but the seat backs seem pretty solid and "sound" proofed... opening them up a bit might really help get bass into the cabin. Hole saw?


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Andrei, are you planning to "vent" the rear seat backs at all? I haven't taken the carpet off to look at what's behind it, but the seat backs seem pretty solid and "sound" proofed... opening them up a bit might really help get bass into the cabin. Hole saw?


Nah, I'm leaving the rest alone. I need to fold one seat down to get the full sound. Making holes will just whistle.

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## XtremeRevolution (Jan 19, 2012)

Oh, btw, the sound is incredible. Pure subsonic awesomeness. It's insane how accurate they are. In this configuration, they outperform the IDQ15 I had for sound quality (hard to believe, I know), and they dig as deep as an IDMax.

They actually sound like a real bass guitar amp. It's just crazy how accurate and musical they are and how loud they get even with deep synthetic bass.

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## Mick (Dec 31, 2011)

And there's still room for groceries lol.

So the back is going to be open, with 1 or north seats down?




Smurfenstein said:


> Ohhh man, I need to stop looking at this thread or else I'm going to kill myself waiting until I get everything ready for Matt to build mine D:


No you need to hurry up and get this so i can hear it in person.

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## XtremeRevolution (Jan 19, 2012)

Mick said:


> And there's still room for groceries lol.
> 
> So the back is going to be open, with 1 or north seats down?
> 
> ...


Yep, back has to be down with one or two seats in order to hear the subs the way they need to be heard. If I have back passengers, chances are they won't want to have two 18s blasting behind their heads anyway. 

There is a LOT of room left. The total depth used is no more than 12" to the bottom of the back seat and the sub magnets are 1/2" from the backs of the seats. 

I have massive SPL, incredible sound quality, less weight added than a sub box, and a very small trunk space penalty. The only disadvantage is that I can't use the pass-through for long items.

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## Mick (Dec 31, 2011)

That's what the roof is for. I've strapped a Christmas tree to my old car and 2x4's out the sunroof lol. 
Get the roof rack to tie down the mdf sheets.

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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> Oh, btw, the sound is incredible. Pure subsonic awesomeness. It's insane how accurate they are. In this configuration, they outperform the IDQ15 I had for sound quality (hard to believe, I know), and they dig as deep as an IDMax.
> 
> They actually sound like a real bass guitar amp. It's just crazy how accurate and musical they are and how loud they get even with deep synthetic bass.


It doesn't surprise me that you are hearing such great SQ based on two things; one, the amount of technical reasoning for your choice in sub drivers (good job, BTW!), and two, my own experience with reducing the impact of the car's trunk on SQ.

I'll explain #2. A buddy of mine had a Chevy Beretta many many moons ago. We shoehorned two 15" Orion Hott Setup subs into the trunk in a vented cabinet. The subs and vents faced rearward. These were cheap subs and in a vented cabinet they didn't exactly sound very good, but as you say "Cone Area is King" and there was lots of that so it was painfully loud even with a 300W amplifier.

I couldn't get over how much his trunk and tail lights were flexing when bass would hit, so I convinced him that removing the tail lights and drilling a bunch of holes in his car was a good idea. This was so we could attach the whole rear of the car to the front of the sub enclosure with threaded rods… we passed them through the sheet metal and screwed them right into the enclosure. We also put an MDF panel on the inside of the vertical section of the trunk lid directly behind the subs.

This little experiment was a literal transformation in SQ. Reducing the amount of flex in the trunk panels increased the accuracy, the impact and the SPL of those cheap-azz 15's so much you'd swear they were different subs altogether. They now hit so hard and with such "snap" they would literally make you flinch, and they maintained their SQ and impact well past 100Hz.

XR, with your previous sub (and any other sub, for that matter) sitting behind the seat and firing rearwards, sound reflected off the rear of the trunk cavity would introduce a delay or "smear" in the sound even though we're talking about long wavelengths. As well, that reflected sound would be colored by the flexing of trunk panels. I've always tried to locate my subs as far rearward as possible to minimise the delayed reflections, but dealing with trunk panels resonating and coloring the sound is inevitable since I'm not in a position of wanting to "reinforce" my cars with the barbaric methods of my youth. 

Free-air mounting as you've done eliminates all of that trunk panel sourced nastiness from the front wave of the sound, and also gives a much shorter and direct path between the sub and your ears. The trade-off, as you've pointed out, is the total loss of the pass through in the trunk, but you have gained so much aural pleasure you might not notice!

You've got me thinking rather seriously about doing something similar in my car... dammit!


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## Smurfenstein (Nov 16, 2011)

Mick said:


> No you need to hurry up and get this so i can hear it in person.


Donations to speed up the process are greatly appreciated haha.


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## H3LLON3ARTH (Dec 16, 2011)

Shooy I can take some donations too lol I am trying to pay gor a $400 subwoofer.

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## Blue Angel (Feb 18, 2011)

So XR, how long until we get a frequency response graph? Do you still plan to block off the rear deck, or have you done that already and I'm just not paying attention?


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## tecollins1 (Nov 6, 2011)

hes been out of state visiting Fam. so hes prob been busy getting back on track with work.


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## Fun_Bucket (Feb 12, 2013)

Amazing work. I contemplated doing an IB, and might even have a go at it when i get my tax return. Have you head anything about a factory eq curve affecting the subs performance ? I'm not using a processor just high level inputs on the amp for now, and i'm not getting very good results with 2 x peerless 830952's. 

Do you find the rear of the Cruze resonates a lot? I've just added some body deadner to the internal walls of the sub enclosure and ordered a bulk pack so hopefully things will improve. I had the LPF set at about 80-90, but i'm finding anything above 50-60hz is causing the resonating the most.


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## XtremeRevolution (Jan 19, 2012)

Fun_Bucket said:


> Amazing work. I contemplated doing an IB, and might even have a go at it when i get my tax return. Have you head anything about a factory eq curve affecting the subs performance ? I'm not using a processor just high level inputs on the amp for now, and i'm not getting very good results with 2 x peerless 830952's.
> 
> Do you find the rear of the Cruze resonates a lot? I've just added some body deadner to the internal walls of the sub enclosure and ordered a bulk pack so hopefully things will improve. I had the LPF set at about 80-90, but i'm finding anything above 50-60hz is causing the resonating the most.


What box specs are you using with those Peerless drivers?

I can't stand anything but IB now. The difference is phenomenal. Pianos actually sound lifelike with these drivers. You can hear the low notes incredibly clearly. I have my LPF at around 100-110h. A bit high, but these drivers are designed to play much higher clearly. 
There is a factory EQ curve but it doesn't seem to affect the lower frequencies aa much as it does higher ones.

The rear of the car does resonate. I have SDS CLD tiles on the rear deck and on all of the panels in the trunk and those are extremely effective. Best product out there for vibration dampening. Having drivers play directly into the cabin though makes a massive difference. I can play Cinderella - Dead Man's Road and the kick drums sound exactly like they're behind your head. It's pretty crazy. 

Vibration deadener inside the sub box will do nothing. Put some mineral wool or fiberglass insulation along the inside walls to help reduce harmonic distortion, but if your box is resonating, it's not built right. Check out the bracing I make in my sub box thread. 

All in all, I need to put some CCF (closed cell foam) between the rear deck and the walls to keep that from buzzing, but that's it. The baffle itself probably helps add some rigidity to everything also. 

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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> So XR, how long until we get a frequency response graph? Do you still plan to block off the rear deck, or have you done that already and I'm just not paying attention?


I will block off the 6x9 holes, but that's about as far as I'll go with the rear deck. 

I haven't had a chance to get a frequency response measurement. I'll be lucky if I can get the trunk carpet panels back in before the meet. 

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## XtremeRevolution (Jan 19, 2012)

After 4 hours of tuning...










My doors are going to need some more CLD tiles because that midbass it annihilating them.


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## jstoner22 (Aug 21, 2012)

bigger pic? can't read a thing on that


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## EcoDave (Mar 7, 2013)

jstoner22 said:


> bigger pic? can't read a thing on that


This forum shrinks pics, You can always try right clicking and opening in new window or tab to get the real size.
http://img850.imageshack.us/img850/8113/xtremerevolutioncruze.png


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## H3LLON3ARTH (Dec 16, 2011)

jstoner22 said:


> bigger pic? can't read a thing on that


right click hit open in new tab

sorry didnt read above post lol


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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> After 4 hours of tuning...


I would make a WAG that your sub ~35Hz response drop is related to leakage. Sealing up that rear deck is only going to make more awesome.


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> I would make a WAG that your sub ~35Hz response drop is related to leakage. Sealing up that rear deck is only going to make more awesome.


Yeah I'm pretty sure that's where it's coming from. Hopefully I'll have some time to correct that.

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## Blue Angel (Feb 18, 2011)

"correct" is a pretty strong word. How about "make better"? 


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## XtremeRevolution (Jan 19, 2012)

Figured I'd post a quick update. I spent another 1.5 hours tuning today. I liked it a lot better, but something just wasn't quite right. Well, I figured it out. I really wanted to avoid going this route, but I was left with no choice. I took a measuring tape and measured the distance from my ears to each speaker, then used the distances to fine tune time delay. I'll post the numbers here if anyone wants to know what I used so they can use them with their own miniDSP. 

The end result is that it sounds a whole lot better. There's a bit of added clarity, but most importantly, I got rid of some fatigue and distortion around 2500KHz. You would be surprised by what I had to do to the PEQ to make the car sound good. Either the Cruze does not work well acoustically from a frequency response standpoint, or the factory head unit has a lot of equalization that needs to be reversed. 

Either way, I have a feeling people are not going to want to get out of my car at the meet.


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## Blue Angel (Feb 18, 2011)

My personal experience with Time Delay has been so positive that I can't imagine building a remotely serious sound system without it. The transition from subs to midbass seems to tighten up considerably, frequency response appeared to smooth out quite a bit (but I did not measure to verify), and imaging improved so much there was no contest. Everything just seems to blend together a little nicer with TD, and transients appear much tighter.

I was able to get a stable sound stage with both sides playing at full volume, something I could never do before. In fact, I ended up throwing out my "calculated" TD settings and setting my front stage with the amount of delay on the left front channel. Calculated values got me close, but tweaking by ear put the image solidly between the center of the dash and the steering wheel. Trying to push the image any farther left didn't sound natural in that system, but as it was it sounded and imaged very well considering what it was.

I demonstrated the TD imaging effect for a friend of mine who actually competed in car audio. His system was installed and tuned for him as he was not very technical with audio. I showed him how I could "walk" the image across the car simply by delaying the RF channel (for him in the passenger seat) while leaving both channels at the same level; he was blown away and promptly got his installer to order up a DSP unit. His system being in a truck which is wider and harder to image in, benefitted HUGE from a little TD, even more than my car did.

I haven't started my Cruze system yet, but when I do I will be sure to make TD part of the equation. I'm really liking the flexibility of that MiniDSP… it just seems perfect for a total geek - endless tweakability!


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## jstoner22 (Aug 21, 2012)

XtremeRevolution said:


> Figured I'd post a quick update. I spent another 1.5 hours tuning today. I liked it a lot better, but something just wasn't quite right. Well, I figured it out. I really wanted to avoid going this route, but I was left with no choice. I took a measuring tape and measured the distance from my ears to each speaker, then used the distances to fine tune time delay. I'll post the numbers here if anyone wants to know what I used so they can use them with their own miniDSP.
> 
> The end result is that it sounds a whole lot better. There's a bit of added clarity, but most importantly, I got rid of some fatigue and distortion around 2500KHz. You would be surprised by what I had to do to the PEQ to make the car sound good. Either the Cruze does not work well acoustically from a frequency response standpoint, or the factory head unit has a lot of equalization that needs to be reversed.
> 
> Either way, I have a feeling people are not going to want to get out of my car at the meet.



I'm quite surprised that you weren't using time alignment up until now. It is a definite staple. Fine tuning by ear is a must for one simple reason - Reflections (the measured value will never be the exact 'right' value because of this)
Ensure that you re-evaluate your individual driver levels now though if you haven't already. T/A can slightly skew necessary values.
Does the mini DSP allow you to mute individual driver or select preouts? This will make T/A much easier for other that want to attempt it.

If you were utilizing a phase option, this may need altered as well.


I'm glad to hear it is all coming together though! It an awesome system you are building


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## Blue Angel (Feb 18, 2011)

jstoner22 said:


> Fine tuning by ear is a must...


Agreed 100%

Using measured values got me almost dead-on for blending my sub to my RF channel (sub has zero delay, RF has small delay). I found that using slightly less delay on the RF helped keep the mid-bass image forward of the seating position. It also gave the bass a little more perceived "attack" as the midbass frequencies had a slight lead on the sub.

The highest delay is on the LF channel since it's closest to you, but the measured delay is not enough as it will try to place the center of the stage directly in front of you. This causes the left side of the image to be severely compressed since the LF drivers are almost in front of you at a very shallow angle. Delaying the LF channel a little more will move the center of the image a little more to the right, broadening the left channel's "width" and compressing the right slightly, making the left-right balance a little more harmonious and pulling the stage away from the left A pillar. It also just seems more "natural" since visually you would imagine the stage as the full width of the dash in the car.

Of course, every car will react different based on interior proportions and driver locations, so this is just general commentary. The "sweet spot" for the Cruze is something I have yet to tinker with. Also, I would imagine the upper bass frequencies will not be lacking at all with this dual pro driver 18" free-air setup.

Andrei, do you plan to add another MiniDSP to your sub channel for ultimate control? Tell me with a straight face it hasn't crossed your mind...


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> My personal experience with Time Delay has been so positive that I can't imagine building a remotely serious sound system without it. The transition from subs to midbass seems to tighten up considerably, frequency response appeared to smooth out quite a bit (but I did not measure to verify), and imaging improved so much there was no contest. Everything just seems to blend together a little nicer with TD, and transients appear much tighter.
> 
> I was able to get a stable sound stage with both sides playing at full volume, something I could never do before. In fact, I ended up throwing out my "calculated" TD settings and setting my front stage with the amount of delay on the left front channel. Calculated values got me close, but tweaking by ear put the image solidly between the center of the dash and the steering wheel. Trying to push the image any farther left didn't sound natural in that system, but as it was it sounded and imaged very well considering what it was.
> 
> ...


It does make a very big difference. I've just been too lazy for a while, and I wanted to see if I could make it sound good enough for everyone in the car instead of just for the driver's seat, but the more I tried tuning, the more I realized that it's impossible. I've always known the car environment to be absolutely terrible for sound quality, but I finally gave in after realizing that I couldn't achieve my goals without time delay. 

The miniDSP is the perfect keep tool. I am absolutely loving tuning this sound system with it. The parametric equalizers on the advanced plugin are, much more powerful than a 31-band equalizer. 



jstoner22 said:


> I'm quite surprised that you weren't using time alignment up until now. It is a definite staple. Fine tuning by ear is a must for one simple reason - Reflections (the measured value will never be the exact 'right' value because of this)
> Ensure that you re-evaluate your individual driver levels now though if you haven't already. T/A can slightly skew necessary values.
> Does the mini DSP allow you to mute individual driver or select preouts? This will make T/A much easier for other that want to attempt it.
> 
> ...


I did indeed fine tune by ear. I discovered that going off of the measurements resulted in an imaging that was just a tad bit to the center of the dash, and I wanted something more up-front and in my face. I achieved that result and eliminated the fatigue I was fighting to boot. 

The miniDSP does indeed allow me to mute individual driver pre-outs. I may try to run ARTA on the system again later to see how close I was to the measured time delay. 

All that's left now is to get that infinite baffle setup finished and get an amp rack made. I bought a GT-475 to replace the GT-40, simply because the GT-475 matches the GT-2300 I have and the GT-40 is one generation older. 



Blue Angel said:


> Agreed 100%
> 
> Using measured values got me almost dead-on for blending my sub to my RF channel (sub has zero delay, RF has small delay). I found that using slightly less delay on the RF helped keep the mid-bass image forward of the seating position. It also gave the bass a little more perceived "attack" as the midbass frequencies had a slight lead on the sub.
> 
> ...


Indeed, the highest delay was in the driver side tweeter, then the driver side door speaker, then the passenger tweeter. Since the subs were actually closer to me than the driver side door speaker, I left that as the baseline with zero time delay. 

The upper bass frequencies are not lacking at all. I also boosted 125-210khz to get some really powerful drum snaps. It sounds incredible. 

I have contemplated a second miniDSP for the subwoofer. It has crossed my mind on many occasions, and it would cost me only about $110. Definitely tempting. 

The miniDSP hands down destroys ANY DSP I have seen for less than half the price.


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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> It does make a very big difference. I've just been too lazy for a while, and I wanted to see if I could make it sound good enough for everyone in the car instead of just for the driver's seat, but the more I tried tuning, the more I realized that it's impossible...
> 
> ...The upper bass frequencies are not lacking at all. I also boosted 125-210khz to get some really powerful drum snaps. It sounds incredible.


I ended up with separate delay presets for both front seats so others could hear what I was hearing. That was one really nice feature on that Alpine deck; six presets for both EQ and TD.

I can't imagine how good your midbass sounds - it would almost be worth the drive to Chicago just to check it out! 

If you do a MiniDSP for your subs you can do separate amps for each sub and delay the driver's side sub so they smack you in the back of the head at _exactly_ the same time!


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> I ended up with separate delay presets for both front seats so others could hear what I was hearing. That was one really nice feature on that Alpine deck; six presets for both EQ and TD.
> 
> I can't imagine how good your midbass sounds - it would almost be worth the drive to Chicago just to check it out!
> 
> If you do a MiniDSP for your subs you can do separate amps for each sub and delay the driver's side sub so they smack you in the back of the head at _exactly_ the same time!


Lol. The midbass is to die for. If you make a trip, I'll let you play with the minidsp!

I wouldn't dream of another amp. One gt-2300 is enough lol. They are also 8ohm drivers, so I wouldn't actually gain any power since I now have them wired to 1 ohm.

After some measuring, I discovered that my tweeters are useless below 2000Hz so I have them crossed there with a 48db/ octave crossover and a -16db tank at 1850Hz due to some distortion so I make sure I never, ever hear it. I have those CSS tweeters going in as soon as I have the time. Those are the ones with the xbl^2 neo motors and a massive 1.85mm xmax. I can cross those down to 1800Hz flat and keep an audiophile with a microphone happy. Response starts to fall after that. 

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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> I wouldn't dream of another amp. One gt-2300 is enough lol. They are also 8ohm drivers, so I wouldn't actually gain any power...


Yeah, but you know that I know that you know you could make people deaf with about seventeen watts...


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Yeah, but you know that I know that you know you could make people deaf with about seventeen watts...


This is true. 100.7db sensitivity with one watt. 112.7 with 16 watts..

And $385 shipped for the pair.

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## Keyzbum (Sep 11, 2011)

XtremeRevolution said:


> They are also 8ohm drivers, so I wouldn't actually gain any power since I now have them wired to 1 ohm.


two 8ohm drivers wired to 1ohm ????? 
dude,, you just made the magic smoke come out of the little black box in my head..
how do you wire that?


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## XtremeRevolution (Jan 19, 2012)

Keyzbum said:


> two 8ohm drivers wired to 1ohm ?????
> dude,, you just made the magic smoke come out of the little black box in my head..
> how do you wire that?


LOL. That was a typo from my phone. Two 8 ohm drivers wired to 4 ohm. 1,000W RMS on an amplifier that is more than happy to deliver the power.


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## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> And $385 shipped for the pair.


Just curious... where did you get them from? PE sells them for $214.39/ea right now:

Peavey 18" Low Rider Subwoofer Speaker Driver 294-301


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Just curious... where did you get them from? PE sells them for $214.39/ea right now:
> 
> Peavey 18" Low Rider Subwoofer Speaker Driver 294-301


Audiosavings.com's ebay store.

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## Blue Angel (Feb 18, 2011)

Hey Andrei, have you tested the SPL abilities of this cone area domination yet? I'm betting a single 18 would be plenty for most people, including me.

I remember how 136db felt with the Stroker 15... painful. If one free air 18 got me even 130 it would be plenty.


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## tecollins1 (Nov 6, 2011)

Blue Angel said:


> Hey Andrei, have you tested the SPL abilities of this cone area domination yet? I'm betting a single 18 would be plenty for most people, including me.
> 
> I remember how 136db felt with the Stroker 15... painful. If one free air 18 got me even 130 it would be plenty.
> 
> ...


Yeah what this guys said!
Need to post up a video soon!!!


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Hey Andrei, have you tested the SPL abilities of this cone area domination yet? I'm betting a single 18 would be plenty for most people, including me.
> 
> I remember how 136db felt with the Stroker 15... painful. If one free air 18 got me even 130 it would be plenty.
> 
> ...


Matt was estimating a total SPL in the low 130s if I remember correctly for the pair. Keep in mind that this will produce those numbers across a wide frequency range, not a ported one note wonder, and it will do that with extremely low distortion. That's something you can only get with lots of cone area. Its a different kind of SPL. It literally is just like being in the front row of a concert. 

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## XtremeRevolution (Jan 19, 2012)

tecollins1 said:


> Yeah what this guys said!
> Need to post up a video soon!!!
> 
> 
> Sent from AutoGuide.com App


There's not much to see though. The excursion is not anywhere near that of your IDMax. I probably will anyway though once it's done.

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## Fun_Bucket (Feb 12, 2013)

XtremeRevolution said:


> What box specs are you using with those Peerless drivers?
> 
> I can't stand anything but IB now. The difference is phenomenal. Pianos actually sound lifelike with these drivers. You can hear the low notes incredibly clearly. I have my LPF at around 100-110h. A bit high, but these drivers are designed to play much higher clearly.
> There is a factory EQ curve but it doesn't seem to affect the lower frequencies aa much as it does higher ones.
> ...


They are in 1.35 cu ft per driver, heavily stuffed. The paint on deadner actually made a huge difference, it's in a pre fab enclosure so it must have been resonating a lot. I've dropped the LFP down to 60hz, i find anything above this draws the sound stage towards the rear too much. (note i have no rear speakers) 

Now the hunt is on to find a mid that will play down to 60hz with a little authority. I haven't pulled the pillars off yet to look at the tweeter mounting, is it a flush mount?


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## XtremeRevolution (Jan 19, 2012)

Fun_Bucket said:


> They are in 1.35 cu ft per driver, heavily stuffed. The paint on deadner actually made a huge difference, it's in a pre fab enclosure so it must have been resonating a lot. I've dropped the LFP down to 60hz, i find anything above this draws the sound stage towards the rear too much. (note i have no rear speakers)
> 
> Now the hunt is on to find a mid that will play down to 60hz with a little authority. I haven't pulled the pillars off yet to look at the tweeter mounting, is it a flush mount?


I'm crossing at 110hz right now with a 24db/octave filter and I have no issues with the sound stage. I was crossing at 90hz with my IDQ15 and it sounded great there too. What mids are you currently using?

You're not going to find a mid that will play linear to 60hz with authority. The key there however is your definition if authority. It will really depend on how loud you want to go. The Silver Flutes are by far the best driver I have ever used in their price range for a driver that is capable of being used in a 2-way with respectable excursion and a strong midbass. Problem is, they're out of stock right now. 

Crossing your subs at 60hz really gives them very little actual bandwidth. You're practically running 30-50hz before you start to drop off. 

The prefabbed enclosure is where you had the issues. If your paint-on deadener made a difference inside the enclosure, all it did was reduce some of the resonance, but you still have walls flexing. I'd highly recommend a custom enclosure. 

Tweeters are basically plastic welded onto the back of the pillar covers in two spots which can be cut easily. A replacement tweeter will be interesting to fit, depending on which one you try to use. What are you going to use for a crossover?


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## Fun_Bucket (Feb 12, 2013)

I'm building an enclosure and floor in my spare time, i threw the subs in a pre fab that i got a good deal on so i could at least run the equipment in the mean time. I'm using the stock front stage, i have an audison sr4 which i'll use to run the front active with the in built crossover until i can afford a processor. 

I'm thinking about using SB acoustics drivers for the front if i keep the budget down. Otherwise i'd be keen to see if a 2'' widebander would fit and work off axis in the factory tweeter housing and then cross to a 6.5 in the door. The opening in which the tweeter plays through in the pillar is about 50mm, and looks to have about the same amount of depth to play with, if i was really lucky i could fit something there and have it look factory.

All the 6.5's i've seen that will play down to my xover point won't play up to the tweeter crossover point on their own, though many 2'' FR's will play both down to that point, and will also play plenty high enough for my liking. The fact that they often don't go right up to 20khz suits me just fine, the best sounding speakers i had only ever went up to about 16khz and i never noticed anything missing and thought they sounded smoother.

I was thinking something along the lines of the Vifa NE65, paired with CDT M6+. I know i've really limited the bandwidth on the subs by crossing over so low, but without any tuning capabilities the sound stage it too easily drawn to the rear. I would like to go as low as possible up front obviously without hacking the doors up to do a 3 way.


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## XtremeRevolution (Jan 19, 2012)

Fun_Bucket said:


> I'm building an enclosure and floor in my spare time, i threw the subs in a pre fab that i got a good deal on so i could at least run the equipment in the mean time. I'm using the stock front stage, i have an audison sr4 which i'll use to run the front active with the in built crossover until i can afford a processor.
> 
> I'm thinking about using SB acoustics drivers for the front if i keep the budget down. Otherwise i'd be keen to see if a 2'' widebander would fit and work off axis in the factory tweeter housing and then cross to a 6.5 in the door. The opening in which the tweeter plays through in the pillar is about 50mm, and looks to have about the same amount of depth to play with, if i was really lucky i could fit something there and have it look factory.
> 
> ...


The 6.5" silver flutes will play up to 4k beautifully with a steep crossover slope and a tank at the 5-6k breakup. Compliments of a very strong motor, healthy xmax, and a pressed wool/paper cone. It cannot be beat at the $30-$50 price point for a 2-way. Even the 8" version will cross up to 2.5k very nicely. I didn't just recommend them on a whim. 

Finding something to play off axis will be a challenge. I would sell your dsp and get a minidsp. $150 shipped. Biggest reason is that you need to tune a low shelf for all frequencies under 4k on just the tweeters by about 4-5db. The design of the pillars and the tweeters' proximity to the windows reflects a lot of sound in that range, while the frequencies above that range have increasingly too small of a wavelength to be reflected as severely. Take a pink noise frequency response measurement of just the tweeter and you'll see what I mean. It will drive you crazy. It has been driving me insane for the past year till I decided to measure drivers individually and found where the problem was.

That Vifa waveguide tweeter I've been recommending crosses perfectly at 2250Hz with a 4th order filter and 2100hz with an 8th order filter. I've measured the harmonic distortion to verify those as good crossover points so other people don't have to.

I am not at all a fan of full range drivers. Even if you can place them perfectly on-axis, the highs still sounf strained and lacking airy detail compared to a mediocre tweeter.

Sent from AutoGuide.com App


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## Fun_Bucket (Feb 12, 2013)

Well i just pulled the A pillar trim off, there's no way anything is going behind that. I cut around the plastic mould on a Vifa BC25SC06 and was able to test tape it into place and clip the pillar back in. Not sure if i want to go spending money on tweeters to cut them up and find they won't fit. Perhaps i should use what i have on hand and glue the Vifa's in and fill around them. I have spare sets of Aurasound ns6 drivers that someone reviewed well in their car door.


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## XtremeRevolution (Jan 19, 2012)

For the past 6 months or so, I haven't had any light in the trunk when I open it. I figured one of those cheap LED lights I bought went out or something. Too lazy and didn't have enough time to find the few spares I had laying around who knows where, then I pulled my amp back in February to test with Terry's amp that we believed to be bad so I didn't have any sound till now. 

Well, I got the entire system pulled out, carpeted, and reinstalled with the factory trunk panels recently so I went out for a drive again. Turned up the bass and had some fun. Then popped the trunk and what do you know...LED was sitting on the floor. Turns out the bass from the two 18s vibrated the bulb out of the socket. I'll have to keep an eye on that...


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## justdofit (Apr 17, 2014)

XtremeRevolution said:


> For the past 6 months or so, I haven't had any light in the trunk when I open it. I figured one of those cheap LED lights I bought went out or something. Too lazy and didn't have enough time to find the few spares I had laying around who knows where, then I pulled my amp back in February to test with Terry's amp that we believed to be bad so I didn't have any sound till now.
> 
> Well, I got the entire system pulled out, carpeted, and reinstalled with the factory trunk panels recently so I went out for a drive again. Turned up the bass and had some fun. Then popped the trunk and what do you know...LED was sitting on the floor. Turns out the bass from the two 18s vibrated the bulb out of the socket. I'll have to keep an eye on that...


Would love to see how this looks all buttoned up and carpeted. Fantastic build!


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## XtremeRevolution (Jan 19, 2012)

Pictures attached.

Sent from AutoGuide.com App


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## Mick (Dec 31, 2011)

Had forgotten about this thread. Good reading.


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## justdofit (Apr 17, 2014)

Very very nice mate! Excellent use of space!


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## hificruzer226 (Mar 27, 2013)

Sunday is my starting day for this along with a ton of other stuff. I need a friend and a 30 pack.


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## hificruzer226 (Mar 27, 2013)

WoofersEtc.com - Dark Blue 1000.2 - Audiotec Fischer Helix Mono 1950W Amplifier

now on sale for $269 perfect for this set up on a budget!

The digital amplifier DARK BLUE 1000.2 are pure subwoofer driver. The DARK BLUE 1000.2 model are equipped with adjustable active crossovers (35 - 250 Hz), adjustable subsonic filters (10 - 50 Hz) and a remote controlled bass boost (0 - +18 dB at 45Hz)and a phase control adjustable from 0 - 180°.

Power RMS/Musik at 1 x 4Ohm : 1 x 500/1000 Watt
Power RMS/Musik at 1 x 1 Ohm : 1 x 1000/2000 Watt
Power RMS/Musik at 1 x 2 Ohm: 1 x 800/1600 Watt
Power RMS/Musik at 1 x 4 Ohm bridged: 1 x 1600/3200 Watt
Power RMS/Musik at 1 x 2 Ohm bridged: 1 x 1950/3900 Watt
Frequency range : 18 Hz - 250 kHz
Bassboost adjustment: 0 - 18 dB
Frequency range Lowpass: 40 Hz - 250 Hz
Total harmonic distortion: < 0,33 %
Signal to noise ratio: > 96 dB
Input impedance: 10 kOhm
Input sensitivity: 240 mV - 6 V
Fuse: external
Dimensions (H/W/D) in mm : 64 x 282 x 585
Weight netto: 7,8 kg


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## XtremeRevolution (Jan 19, 2012)

An orbital sander is an awesome tool for this job since you have to shave off the wood to make it fit well. Make sure you have one handy.


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## hificruzer226 (Mar 27, 2013)

Ive got a DA and a belt sander that should do the trick. My Zapco amp fell through my rep was being a dingo.


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## XtremeRevolution (Jan 19, 2012)

hificruzer226 said:


> Ive got a DA and a belt sander that should do the trick. My Zapco amp fell through my rep was being a dingo.


Here are a few tips to make your job easier. 

That should do. The mounting points are pretty self-explanatory. Just be careful when drilling the holes into the body. Check and double check. You'll also need a router to counter-sink some of the bolts, either on the baffle or on the frame itself. Also, when you measure the height of the frame from the floor, be sure to account for the thickness of the carpet. I didn't. 

Don't cut the baffle until you've measured the width with the frame bolted in and the trunk covers back in. I used hurricane nuts to bolt the baffle to the frame; don't drill the holes for the hurricane nuts till you have all of the trunk covers back in and the frame carpeted. I made that mistake and getting it back together after installing the carpeting was a bit of a PITA. Also, some CCF will be needed for the rear deck pad as it will vibrate a bit. Use oil when drilling the 1/2 hole. I ended up butchering one 1/2 drill bit. When drilling the holes through the sides of the car, be careful not to punch a hole in the shock cover. It's easy to do so. When using metal washers on top of neoprene washers on the sides of the car, you may need to shave an edge on the washer due to the contour of the car's sheet metal. 

I used t-nuts and stainless bolts to mount the subs. I used 1/4" bolts IIRC but I had to widen the holes on the subs as some of the coating had made the holes smaller. Be prepared to have to do that. Also, be prepared to replace the nuts if you use an impact driver to tighten the bolts like I did. I used 1/2" bolts to mount the frame to the car. Don't remember the bolt lengths though. I used all stainless hardware on the outside of the car in addition to neoprene washers to seal. 

Deaden the under-body heat shield or it will buzz like crazy. 

When making the cutout in the baffle, center the baffle inside the car first and mark the center distance between the top and bottom frame. The cutout will be larger than the top to bottom frame clearance, but the rear opening of the subs will leave barely enough clearance to fit with a 1.25" thick mounting plane. I can take a picture of this if you want to see what I mean. I used a 2" thick baffle, with 3/4" of it being a flush mount. 

If you have a dual bevel miter saw, use that to shave the top corners of the baffle or they won't clear the car's sheet metal. You could shave them off with the sander, but it's easier if you use the miter saw. 

Good luck. I would do a few things differently based on what I learned the first time.

I used: Two bolts for the bottom frame. Two bolts for the top frame. 4 bolts (two on the side and two at the top) for the side frame. Total of 8 bolts. 

When drilling the holes in the baffle to mount it to the frame, try to remember where the frame's bolts are.


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## hificruzer226 (Mar 27, 2013)

Thanks man I dont think most people understand the complexity of this install. This is gonna be a multiday excursion......The more pics the better.


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## hificruzer226 (Mar 27, 2013)

BTW as an installer and fab guy I would recommend checking out this stuff I use some of his stuff. The F.A.S.T rings are pretty cool.
Mobile Solutions - USA - Home


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## hificruzer226 (Mar 27, 2013)

My xtreme Sunday starts today here we go dual 18


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## hificruzer226 (Mar 27, 2013)

My xterme sunday, out with old in with the new. My puppy helped me can see the saw dust on her


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## XtremeRevolution (Jan 19, 2012)

You'll have a fun time getting it all back together with the trunk panels back in. I made the same mistake lol.


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## hificruzer226 (Mar 27, 2013)

XtremeRevolution said:


> You'll have a fun time getting it all back together with the trunk panels back in. I made the same mistake lol.


Im Goin with a full custom trunk, I would have done it the same way it's the best way to ensure s turd build .. small sacrifice for big gain.


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## hificruzer226 (Mar 27, 2013)

Hahaha I'm not even gonna fix that I meant sturdy build lol


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## XtremeRevolution (Jan 19, 2012)

Gotcha. Yeah I was about to say...I got as far as you did, then realized I had to put the trunk panels back in to keep a factory look. Ended up with some fitment issues. I got it all to fit finally but it wasn't easy.


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## hificruzer226 (Mar 27, 2013)

When you put them in you can almost hear how good they are gonna. I haven't got my amp yet...tomorrow but I know when I hear it how's gonna sound and I have never this excited and I've installed thousands


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## XtremeRevolution (Jan 19, 2012)

hificruzer226 said:


> When you put them in you can almost hear how good they are gonna. I haven't got my amp yet...tomorrow but I know when I hear it how's gonna sound and I have never this excited and I've installed thousands


Haha, yeah they are going to sound incredible. They will take a little while to break in since they're pretty stiff pro audio subs, but give them a couple of days and they'll get even clearer.


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## ChrisWorldPeace (Jun 24, 2013)

hificruzer226 said:


> BTW as an installer and fab guy I would recommend checking out this stuff I use some of his stuff. The F.A.S.T rings are pretty cool.
> Mobile Solutions - USA - Home


I agree just my order of FAST rings came in about 2 weeks ago still needing to install them must have for replacing the speakers


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## hificruzer226 (Mar 27, 2013)

So I popped my new amp in the (helix amp), it was almost dark by the time I got home and I ran 0awg and fired the amp up. It sounds terrible! 


But that is ok for several reason, my trunk is nothing but exposed sheet metal right now, I didnt have time to make any adjustments, I have a crappy line level (at the moment) and my rear deck is completely exposed. That being said hopefully I will have time to fix the majority of it today. You know its bad when you can actually hear the metal flexing. lol


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## BU54 (Nov 24, 2014)

Are these the speakers that I can hear 1/2 mile away, then when I see the car the bumper is vibrating and bolts are falling off the vehicle?


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## hificruzer226 (Mar 27, 2013)

1/2 mile is a stretch.... lol.

The purpose of this build is accuracy and decent spl from a wide band frequency range. I would bet just from initial listening impressions 20 minutes no tuning I could imagine with my 1600wrms I could see high 130db but I dont want it to be up there.


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## XtremeRevolution (Jan 19, 2012)

hificruzer226 said:


> 1/2 mile is a stretch.... lol.
> 
> The purpose of this build is accuracy and decent spl from a wide band frequency range. I would bet just from initial listening impressions 20 minutes no tuning I could imagine with my 1600wrms I could see high 130db but I dont want it to be up there.


Mid to high 130db range is about what these are caps of but a pair of 12" subs in an SPL box are likely to be louder. 

What most people don't understand is that you can't get output out of the same size subwoofer without compromising sound quality in some way. There are a few exceptions but the louder you make the enclosure, the more that sound quality is compromised. Those loud subwoofers have no range; one note wonders that don't sound musical. Being able to produce reasonably high output in addition to a wide frequency range is the challenge that these subwoofers address successfully.


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## hificruzer226 (Mar 27, 2013)

XtremeRevolution said:


> What most people don't understand.


I think we are on the same page, I personally don't care if nobody else ever gets it. Simply because I do. None the less the are starting to break in nicely. Though I was hoping to get a much stronger infrasonic response, suppose that will come after full break in. Was there a huge dip below 50hz in the factory tuning that you noticed when tuning? 
It really makes me anxious to build my dash pods and building my doors. I just did a full system for a customer of mine and it pissed me off lol. If I didn't join this forum and see this thread I would be running JL Audio 13.5TW5 in my cruze god those things are amazing and it blows my mind the
y are shallow mount woofers


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## hificruzer226 (Mar 27, 2013)

God these things sound incredible!!! I cant wait to get my front stage up and running! Dave Mathews "Dodo" sounds pretty sweet


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## hificruzer226 (Mar 27, 2013)

I created a pandora station for dave mathews just because carter beufords kick sounds awesome with these.


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## XtremeRevolution (Jan 19, 2012)

Now you see what people were so impressed with at the last Lordstown meet. I truly believe you cannot find a better value for the Cruze than these two 18s. Those drums sound simply perfect. 

I have them crossed at 125hz.


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## hificruzer226 (Mar 27, 2013)

XtremeRevolution said:


> Now you see what people were so impressed with at the last Lordstown meet. I truly believe you cannot find a better value for the Cruze than these two 18s. Those drums sound simply perfect.
> 
> I have them crossed at 125hz.


What slope?


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## XtremeRevolution (Jan 19, 2012)

hificruzer226 said:


> What slope?


24db.


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## hificruzer226 (Mar 27, 2013)

Bump


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## pandrad61 (Jul 8, 2015)

If only yall lived closer to me. i know quite a lot of wrenching but sound system is where i fall entirely flat.


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## hificruzer226 (Mar 27, 2013)

its all laid out here for you


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## pandrad61 (Jul 8, 2015)

Yah this is way out of my league, i can replace speakers and drill for speakers component set up and hook up a deck with crutchfield pre done harness that i hand solder. plus i don't have access to carpentry tools anymore or any tools needed, all my construction buddys went under so no more tools


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## XtremeRevolution (Jan 19, 2012)

This definitely isn't the install that a novice should attempt if they want professional results that last. It has a few challenges people will need to be aware of.


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## pandrad61 (Jul 8, 2015)

i could be of great assistance to a project like this but heck i don't know hot to even hook up a amp lol


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