# 6 18's - and going bigger!



## Streetbeat Customz (Mar 19, 2011)

Love the forum fellas, so I would like to share my build.

Vehicle is a 1987 Safari. Sexy i know 

6 18' Incriminator Audio Death Rows. Considered an "sql" subwoofer, its rated @ 1000 watts rms, 3 in 4 layer flatwound aluminum coil. Its a triple stacked 290oz motor. Nothing crazy, but gives a little bump.

I used Audiopipe amplifiers in the past, they do rated power so I figured heck, lets do em. Their cheap!

So 6 1800's, sitting @ .6 per. 1100AH in batteries, 1 200 amp, and 1 300 amp Excessive amperage alternators.

Wall was 49 cu @ displacement tuned to 27 hz, with 440sq in of port.

Built from 1x1 steel tubing the wall is welded into the van. Rear wall is over 9in thick, sides are 4in thick, and baffle is 3in thick. I ended up using around 14 sheets of wood 

Final test on the dash sealed - 157.5 @ 48hz.

I am now going to the new IA Death Penalties, and swapping the 1800s out for 6 AP3000s. Along with adding another 1000ah in batteries. 

I have my own alternator line coming out, so I will have 1 250 amp alt that does 175 amps @ idle, and the 300 is now a 350 amp, with 200 @ idle. They also have the external regulator on them now - as the new AP amps will take up to 16V input.

Enjoy!


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## Patrick Bateman (Sep 11, 2006)

If SPL is the goal, isn't it difficult to get big numbers with a woofer that has a low efficiency bandwidth product?

IE, wouldn't it be easier to hit big numbers with a ton of tens or eights? They generally have a higher EBP than fifteens and eighteens, and that means BIG SPL.


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## thehatedguy (May 4, 2007)

But larger speakers often have more excursion so you get more displacement. And fewer larger speakers are cheaper than a lot of high excurion small ones.


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## Streetbeat Customz (Mar 19, 2011)

Patrick Bateman said:


> If SPL is the goal, isn't it difficult to get big numbers with a woofer that has a low efficiency bandwidth product?
> 
> IE, wouldn't it be easier to hit big numbers with a ton of tens or eights? They generally have a higher EBP than fifteens and eighteens, and that means BIG SPL.


Not exactly..

Look at the record holders in the last few years. Using 1-2 18's. Its all about the build. And this is a muscial setup -not spl.



thehatedguy said:


> But larger speakers often have more excursion so you get more displacement. And fewer larger speakers are cheaper than a lot of high excurion small ones.


This


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## Yankeesound (Jul 11, 2009)

Subbed for more pics, I always loved the look of a wall of woofers, LOL


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## Streetbeat Customz (Mar 19, 2011)

Yankeesound said:


> Subbed for more pics, I always loved the look of a wall of woofers, LOL


In the middle of the rebuild, so ill keep on posting em up!


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## dragonrage (Feb 14, 2007)

Streetbeat Customz said:


> And this is a muscial setup -not spl.


Everyone's probably thinking it, so I'll say it: But you're using IA. Why would you do that in a non-SPL setup? Set up correctly for the drivers or not, you're still not gonna get SQ comparable to many other woofers.


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## Genxx (Mar 18, 2007)

dragonrage said:


> Everyone's probably thinking it, so I'll say it: But you're using IA. Why would you do that in a non-SPL setup? Set up correctly for the drivers or not, you're still not gonna get SQ comparable to many other woofers.


I have heard IA's on several occasions. Don't discount their ability to sound great. The IA Flatlyns are some of the most musical subs I have ever heard. The DAD (Definative Audio Designs) sub line is another one that just sound great that have some crazy output.

Get great numbers and great sound from a sub is like anything else, if your install is jacked so are your numbers and sound.


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## dragonrage (Feb 14, 2007)

I've also heard good things about Flatlyne and considered them until I read the marketing blurb on their site. They are, unfortunately, not what he's using. He's using SPL subs in a supposedly not-SPL setup.

Box setup is a major factor, but there are major inherent differences in the design of the driver itself that directly affect sound quality...


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## thehatedguy (May 4, 2007)

Steve Cook uses IA 18s in his truck and he's done more than OK at the shows he has been to.


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## dragonrage (Feb 14, 2007)

thehatedguy said:


> Steve Cook uses IA 18s in his truck and he's done more than OK at the shows he has been to.


For SPL? That's what I see when I Google him...


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## Genxx (Mar 18, 2007)

Steve Cook is a SPL and SQ car builder, top notch and has done some of the best work around. He was a dominate force in SPL before switching over to SQ comp. where he is a dominate force. I know he has won Best of Best of Show multiple times, MECA MODEX Finals Champion I think twice with a 2nd Place last year.


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## thehatedguy (May 4, 2007)

SQ. He won MECA Modified at SBN this year. And has been either winning or getting 2nds in every major show he has done since he stopped doing SPL and started doing SQ. He's had IA 18s the whole time (dunno about this season since you can't see inside his enclosure any longer).


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## Streetbeat Customz (Mar 19, 2011)

dragonrage said:


> Everyone's probably thinking it, so I'll say it: But you're using IA. Why would you do that in a non-SPL setup? Set up correctly for the drivers or not, you're still not gonna get SQ comparable to many other woofers.


Im sorry your upset with their marketing "blurb".

Why do you get in every thread on every site im on and continously downtalk everything?

Please try and respect things you dont do 





Genxx said:


> I have heard IA's on several occasions. Don't discount their ability to sound great. The IA Flatlyns are some of the most musical subs I have ever heard. The DAD (Definative Audio Designs) sub line is another one that just sound great that have some crazy output.
> 
> Get great numbers and great sound from a sub is like anything else, if your install is jacked so are your numbers and sound.


Very well put.


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## Streetbeat Customz (Mar 19, 2011)

YouTube - Streetbeat Customz - Dual Hair Trick

YouTube - Latest burp in the van

YouTube - Hair Trick w/ Jessica (2) - Streetbeat Customz


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## Yankeesound (Jul 11, 2009)

Awesome


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## chad (Jun 30, 2005)

Where are you located in Illinois? I could not tell by your website given the fact that your company's phone number is a cell phone and Incriminator's website does not have it's "#1 dealer" listed as a dealer.

I believe we may be located close.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> But larger speakers often have more excursion so you get more displacement. And fewer larger speakers are cheaper than a lot of high excurion small ones.


That's true, but it's a balancing act. For maximum SPL, you want to find the "sweet spot" where the efficiency bandwidth product of the woofer intersects with the frequency that cabin gain is really starting to kick in.

Of course all of this depends on the EBP, which means that we'd have to know the Thiele Small parameters of the woofers that are winning SPL contests...


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## Streetbeat Customz (Mar 19, 2011)

chad said:


> Where are you located in Illinois? I could not tell by your website given the fact that your company's phone number is a cell phone and Incriminator's website does not have it's "#1 dealer" listed as a dealer.
> 
> I believe we may be located close.


In Champaign - are you insinuating im not an IA dealer? lol the dealer section hasnt been updated in forever, and is going to see 20+ more dealers on it..

If you would like, your more than welcome to call IA and ask em 

Thanks


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## chad (Jun 30, 2005)

If I were a dealer I would be pissed. Let's say I wanted to use IA products, I would go to their website while sitting in my office in URBANA and not even know that you existed  Less money in your pockets right there.


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## Streetbeat Customz (Mar 19, 2011)

chad said:


> If I were a dealer I would be pissed. Let's say I wanted to use IA products, I would go to their website while sitting in my office in URBANA and not even know that you existed  Less money in your pockets right there.


Trust me Chad, I had a discusssion w them last week about the same dang thing.. It's supposed to be updated in the next month. We shall see.

We are pretty well know in this area, but outside of it is where id like to focus.


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## Streetbeat Customz (Mar 19, 2011)

Patrick Bateman said:


> That's true, but it's a balancing act. For maximum SPL, you want to find the "sweet spot" where the efficiency bandwidth product of the woofer intersects with the frequency that cabin gain is really starting to kick in.
> 
> Of course all of this depends on the EBP, which means that we'd have to know the Thiele Small parameters of the woofers that are winning SPL contests...


This is the t/s for the 12' Warden

RE: 2.22 ohms
FS: 47.83 Hz
Qes: 0.36
Qms: 6.43
Qts: 0.34
Le: 2.0 mH
Vas: 11.97 L
BL: 24.86 NA
Cms: 33.219 uM/N 
Mms: 333 grams
Sens: 87.45 1w/1m
BL^2/RE: 278


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## chad (Jun 30, 2005)

Streetbeat Customz said:


> Trust me Chad, I had a discusssion w them last week about the same dang thing.. It's supposed to be updated in the next month. We shall see.
> 
> We are pretty well know in this area, but outside of it is where id like to focus.


No doubt man, good deal. Best of luck!


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## cubdenno (Nov 10, 2007)

OK. But WHERE in Champaign are you located? I live just outside and would love to see a new (I was unaware existed) shop.


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## Streetbeat Customz (Mar 19, 2011)

cubdenno said:


> OK. But WHERE in Champaign are you located? I live just outside and would love to see a new (I was unaware existed) shop.


My product is in Vibez - but I do my big builds in the batcave


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## chad (Jun 30, 2005)

Barbra Streisand's nose?


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## Streetbeat Customz (Mar 19, 2011)

chad said:


> Barbra Streisand's nose?


That is a cave!


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## Twisted-Woodroof (Sep 13, 2008)

Patrick Bateman said:


> That's true, but it's a balancing act. For maximum SPL, you want to find the "sweet spot" where the efficiency bandwidth product of the woofer intersects with the frequency that cabin gain is really starting to kick in.
> 
> Of course all of this depends on the EBP, which means that we'd have to know the Thiele Small parameters of the woofers that are winning SPL contests...



I have seen Iraggi's Caddy with 130+ 5.25" subs it could do 170+ on the AC @ 99 hz. More so than ever people are starting to understand the quarter wave theory and can get louder with single or dual sub set ups. Saying that 16 8" speakers will be louder than 1 18 i doubt. Just my opinion. Sorry to dump on your thread SBC, do what you do mane, I have always been impressed with what you can do with the gear you have.


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## chad (Jun 30, 2005)

Twisted-Woodroof said:


> Saying that 16 8" speakers will be louder than 1 18 i doubt.


sure they would be louder.


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## Twisted-Woodroof (Sep 13, 2008)

chad said:


> sure they would be louder.


Seen it done and have not seen 16 8s or even 24 8s get louder than my single 18 score.


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## cubdenno (Nov 10, 2007)

Twisted-Woodroof said:


> Seen it done and have not seen 16 8s or even 24 8s get louder than my single 18 score.


and what is that? 

Seen some pretty crazy things done with eights. Considering that the surface area of 16 or 24 eight inch drivers is significantly more than a single 18 AND those pesky laws of physics, it should be fairly easy for a decent group of 8" subs to equal and surpass a single 18. Add in the fact that you get less power compression on multiple motors vs a single one. Hell there are you tube vids that show some amazing numbers with groups of 8's.


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## Twisted-Woodroof (Sep 13, 2008)

cubdenno said:


> and what is that?
> 
> Seen some pretty crazy things done with eights. Considering that the surface area of 16 or 24 eight inch drivers is significantly more than a single 18 AND those pesky laws of physics, it should be fairly easy for a decent group of 8" subs to equal and surpass a single 18. Add in the fact that you get less power compression on multiple motors vs a single one. Hell there are you tube vids that show some amazing numbers with groups of 8's.


Never seen a group of 8s do a 154.6 Legal as my single 18 on 2800 watts did.


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## chad (Jun 30, 2005)

cubdenno said:


> Add in the fact that you get less power compression on multiple motors vs a single one.


Bingo.


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## chad (Jun 30, 2005)

Twisted-Woodroof said:


> Never seen a group of 8s do a 154.6 Legal as my single 18 on 2800 watts did.


I've never seen the footprint of a Giraffe either, but we don't get those in Illinois.


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## Patrick Bateman (Sep 11, 2006)

cubdenno said:


> and what is that?
> 
> Seen some pretty crazy things done with eights. Considering that the surface area of 16 or 24 eight inch drivers is significantly more than a single 18 AND those pesky laws of physics, it should be fairly easy for a decent group of 8" subs to equal and surpass a single 18. Add in the fact that you get less power compression on multiple motors vs a single one. Hell there are you tube vids that show some amazing numbers with groups of 8's.


Yep. When you go from eights and tens to fifteens and eighteens, you get an easy bump in maximum SPL, because one big woofer will always embarass one small woofer. But once you start buying small woofers by the pallet, you can hit some crazy numbers.

You can't escape Hoffman's Iron Law, and it simply takes more excursion to hit the low notes. And the SPL rules don't discriminate, it doesn't matter if your box is tuned at 20hz or 40hz.

Combine that with the high EBP of small woofers, and arrays of small woofers can do some serious SPL.


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## Twisted-Woodroof (Sep 13, 2008)

Patrick Bateman said:


> Yep. When you go from eights and tens to fifteens and eighteens, you get an easy bump in maximum SPL, because one big woofer will always embarass one small woofer. But once you start buying small woofers by the pallet, you can hit some crazy numbers.
> 
> You can't escape Hoffman's Iron Law, and it simply takes more excursion to hit the low notes. And the SPL rules don't discriminate, it doesn't matter if your box is tuned at 20hz or 40hz.
> 
> Combine that with the high EBP of small woofers, and arrays of small woofers can do some serious SPL.


Run multiple sub woofers there is this thing called cancellation. When it comes to the TL it does not care how many subs you have it cares about the velocity of the air movement inside the car.


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## cubdenno (Nov 10, 2007)

Cancellation? Of what? Are you referring to having a sub or subs wired out of phase? Let's face it, all we are doing is using a woofer or woofers in an enclosure to pressurize another enclosure (the vehicle interior). I have played enough with single and multiples. And while I run a single 15 I am wishing I had multiple subs to get really loud.


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## Patrick Bateman (Sep 11, 2006)

Twisted-Woodroof said:


> Run multiple sub woofers there is this thing called cancellation. When it comes to the TL it does not care how many subs you have it cares about the velocity of the air movement inside the car.


As long as two woofers are within a quarter wavelength, cancellation isn't an issue. For instance, in a D'Appolito configuration, or "midrange-tweeter-midrange" you need to get the woofers within 1.7" of the tweeter for the unit to act as one, when using a xover of 2000hz. Here's the math:

_13500inches per second / 2000hz / 4 = 1.7"_ (sound travels at 13,500 inches in one second)









Here's a pic of an array which uses this idea. The designer opted for a spacing of one-half wavelength IIRC. This is *less* than perfect, but still pretty good.

But when you move down to subwoofer frequencies, those numbers get pretty huge. For instance, you need to maintain a spacing of 84" to do this trick at 40hz:

_13500inches per second / 40hz / 4 = 84.375"_

That gives you a foot print of *forty nine square feet to play with! (7ft by 7ft)

Neat, huh?
*


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## Chaos (Oct 27, 2005)

Interesting discussion, but I want to see pics of the wall in the van, man!


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## The Baron Groog (Mar 15, 2010)

Twisted-Woodroof said:


> Never seen a group of 8s do a 154.6 Legal as my single 18 on 2800 watts did.


Not far off with 1x 8":
http://www.diymobileaudio.com/forum/diyma-spl-forum/71361-150-2-outlaw-single-8-woofer.html

If you read the post they got it to 151.5dB....


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## Twisted-Woodroof (Sep 13, 2008)

I've seen jacobs crx, impressive with one 8" sub. But outlaw and sealed on the dash "legal" are two different beasts.


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## Twisted-Woodroof (Sep 13, 2008)

seagregory said:


> lol lmao that is all........................... Fisher Price


agreed. :laugh:


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## seagregory (May 18, 2011)

Twisted-Woodroof said:


> I've seen jacobs crx, impressive with one 8" sub. But outlaw and sealed on the dash "legal" are two different beasts.


Agreed


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## Twisted-Woodroof (Sep 13, 2008)

seagregory said:


> Agreed


thanks man, at least you understand what I am saying.


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## Patrick Bateman (Sep 11, 2006)

Twisted-Woodroof said:


> I've seen jacobs crx, impressive with one 8" sub. But outlaw and sealed on the dash "legal" are two different beasts.


4:55 in the morning and couldn't sleep, so thought I'd take a few stabs at why that car is so loud. If I'm not mistaken, Jacob is doing a couple of things right to get really huge SPL.

First, as noted in my previous posts, there's a "sweet spot" where cabin gain and efficiency intersect to give you huge SPL. About 40hz.

Second, and this is the really interesting part, *I think the geometry of his car* is playing a part. In a nutshell, you want a cabin that's about seven feet long. A 40hz sound wave is 28ft long, and by using a cabin that's seven feet long, *you turn the whole damn car into a quarter wave resonator.*

It's tough to find a car that's this short, but the CRX is a good candidate.

I posted some thoughts on this here:

http://www.diymobileaudio.com/forum/1319480-post23.html









Check out this graph of cabin gain that Andy at JBL has posted. In the graph, *we see that the Mini Cooper has almost TEN decibels more gain than a sedan at 50hz.*

The Mini Cooper is probably the closest thing to a CRX being made today, except for that criminally awful Honda CR-Z, so it could be a fine platform for SPL. If you go for something smaller like a truck, you run into an issue where the quarter wave resonance goes up to sixty or seventy hz, because the cabin is TOO SHORT. And sedans have a quarter wave resonance in the twenties, because they're so long.

Possibly the best solution would be a vehicle that's very tall and wide, but short. This would give you a quarter wave resonance around forty or fifty hertz, but higher efficiency than the CRX, CRZ, and Mini Cooper.


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## seagregory (May 18, 2011)

nice info interesting.


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