# Subs sound terrible/fiberglass enclosure



## Slomo051 (Mar 3, 2014)

Ok...worked hard and made a fiberglass sub enclosure. Looks fantastic too...

Long story short...I hooked up the subs, went through the standard checks of checking all wiring, leveling amp settings, etc for the big moment and crap...sound is terrible. Even at low power the subs appear to distort, excursion seems to max out as we'll at low volume. There is absolutely zero low bass response or hardly any bass for that matter.

So using deductive reasoning I hooked up the amp to my old sub box (which is smaller) with infinity kappa subs installed and they sound perfect with great bass range and no distortion. I then got a wild hair and put the kappas in the fiberglass box and they too sounded like complete crap...so it has to be something with the fiberglass box.

What is going on here? Do I have too much deflection back to the woofer cone? Will ensolite lining in box help? Will air leaks cause this? I have poly fill but that didn't seem to help...

I have 2 ea SA10D2 subs, box volume is ~two cubic feet. Sundown recommends a .5 cubic feet for sealed enclosure. Amp is Orion 2400.1D2. Box seems solid and doesn't flex. I believe there is adequate bracing as well. Bottom and sides are 3/4" MDF as well as other parts of the box.

Any help ideas welcome
Thx


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Ensolite will do nothing for a sub box, or any other frequency we humans hear, its only 1/8" thick. 

How thick is the box, how many layers of fg?


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## strakele (Mar 2, 2009)

So the subs want .5 cubic feet each, or 1 cubic foot for two, and you put them in a 2 cubic foot box?

Try putting a bunch of wood scraps or other solid material in the box to take up some airspace?


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## Slomo051 (Mar 3, 2014)

TOOSTUBBORN2FAIL said:


> Ensolite will do nothing for a sub box, or any other frequency we humans hear, its only 1/8" thick.
> 
> How thick is the box, how many layers of fg?


Fg is about 3/16" thick...8 layers


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## Slomo051 (Mar 3, 2014)

strakele said:


> So the subs want .5 cubic feet each, or 1 cubic foot for two, and you put them in a 2 cubic foot box?
> 
> Try putting a bunch of wood scraps or other solid material in the box to take up some airspace?


I unfortunately made the mistake of looking at a ported box volume instead of sealed specs...I had these subs in a bigger (2.5cf) fiberglass enclosure with no filling and they sounded awesome...box just didn't fit car to my liking.

I will try your advice...Thanks !


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## strakele (Mar 2, 2009)

Having the box too big shouldn't make them sound bad, but it will increase excursion. Just figured you may as well try the recommended airspace as part of your troubleshooting. No guarantee it'll help though.

I know you said you checked the wiring, but your description of the problem (distortion, low volume, high excursion, lacking low end) sounds like the two subs are not in phase with each other.


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## SPLEclipse (Aug 17, 2012)

I agree, it sounds like they are wired out of polarity from one another.

But...A leaky/flexing box will sound like that as well. If you want to try and salvage it without spending too much money or investing too much time, get a gallon of long-hair filler, some gloves, and spread that around in an even layer on the inside of the box. It will help add mass, increase strength, and seal any gaps or holes. I used it in my midbass kicks and they are super sturdy.


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## gijoe (Mar 25, 2008)

SPLEclipse said:


> I agree, it sounds like they are wired out of polarity from one another.
> 
> But...A leaky/flexing box will sound like that as well. If you want to try and salvage it without spending too much money or investing too much time, get a gallon of long-hair filler, some gloves, and spread that around in an even layer on the inside of the box. It will help add mass, increase strength, and seal any gaps or holes. I used it in my midbass kicks and they are super sturdy.


Agreed. I would check the box, ensure that it is rigid and completely sealed. Add some more fiberglass to stiffen it up if necessary, and double check the wiring at the subs. I'm guessing you've got a reasonably easy problem to fix. I see that you tried other subs in the same and different enclosures, but did you check your current subs in a different box? This would help rule out whether or not the enclosure is the entire problem.

Good luck!


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## Slomo051 (Mar 3, 2014)

gijoe said:


> Agreed. I would check the box, ensure that it is rigid and completely sealed. Add some more fiberglass to stiffen it up if necessary, and double check the wiring at the subs. I'm guessing you've got a reasonably easy problem to fix. I see that you tried other subs in the same and different enclosures, but did you check your current subs in a different box? This would help rule out whether or not the enclosure is the entire problem.
> 
> Good luck!


Thanks everyone for the ideas and things to check. I read about adding a slurry mix inside to add extra "stiffness" and will most likely try that as a last troubleshooting step after I take others advice I've received. I'll report back with results this weekend when I have time. Also, wiring is good and I thought the same thing (polarity) when I first fired up the system.

Again...thanks all and I welcome any other ideas.


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## Slomo051 (Mar 3, 2014)

***SOLVED** Subs sound terrible/fiberglass enclosure*

For starters thanks to those that replied with advice...

I ended up getting an early work release today so I took the opportunity to take the advice I received...add fiber filler, check leaks, etc. in the process of demounting speakers, pulling wires out, removing poly fill, etc I had a six inch jumper I made that was hidden in the poly fill and what do you know...the jumper was crossed. Yeah...I checked wiring multiple times, at least what I could see. Needless to say I feel like a dumb*** right now.

Anyway, all that hard work paid off and the subs sound terrific in my first home made fiberglass box. It took some work to get this thing designed and to fit/perform in a C6 Vette and still store a targa top in the hatch area.

Thanks again for the help!


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## SPLEclipse (Aug 17, 2012)

Yay! Gotta love when it's something easy.


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## MetricMuscle (Sep 16, 2013)

What? No pics?


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## Notloudenuf (Sep 14, 2008)

MetricMuscle said:


> What? No pics?


Agreed ^^^
This thread is worthless without pics.


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## Slomo051 (Mar 3, 2014)

*Re: **pictues as req**Subs sound terrible/fiberglass enclosure*

Attached are a few pics I snapped before I had the issue to fix for those who wanted to see it. I'm definitely not a professional and this is my 1st try at a sub box...the smaller pod mounted on the top is for a component set. I was definitely pleased after all was fixed and thumping.


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## 07azhhr (Dec 28, 2011)

For a first timer or a professional that turned out really nice. Great job :thumbsup:


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## The Dude (Mar 24, 2007)

07azhhr said:


> For a first timer or a professional that turned out really nice. Great job :thumbsup:


X2 awesome work!


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## Chris659 (Sep 23, 2013)

Wow! It turned out great! especially for a first timer! 

I'd like to see an installed picture too


I'm in the middle of my first enclosure as well. Been working on it on and off when i have time over the past few months. Hope it turns out as nice as yours


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## Slomo051 (Mar 3, 2014)

Chris659 said:


> Wow! It turned out great! especially for a first timer!
> 
> I'd like to see an installed picture too
> 
> ...


I'll send some pics your way when I get done...going out of town for a week tomorrow and plan on finishing install and amp rack when I get back next Wednesday.


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## Slomo051 (Mar 3, 2014)

*Re: Subs sound terrible/fiberglass enclosure**pictures***



Chris659 said:


> Wow! It turned out great! especially for a first timer!
> 
> I'd like to see an installed picture too
> 
> ...


------------------------------------------------------------------

Here are a few pictures of the finished and installed sub box and amp rack. 
Sat time I tried to upload a few only one uploaded...trying again here.

Thanks again to those who chimed in.


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## Slomo051 (Mar 3, 2014)

*Re: Subs sound terrible/fiberglass enclosure**pictures***



Slomo051 said:


> ------------------------------------------------------------------
> 
> Here are a few pictures of the finished and installed sub box and amp rack.
> Sat time I tried to upload a few only one uploaded...trying again here.
> ...


One more...


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## MoparMike (Feb 14, 2012)

Well, seeing as how the SA line of subs prefers ported and you built the box to ported dimensions.......why not port the box? Making some alterations and adding some aero-ports wouldn't be all that tough and it would increase the output of those subs.


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## SPLEclipse (Aug 17, 2012)

Superb install skills. Next time you do a build take some pictures and post it to the Build Log section here, I'm sure we'd all like to see them.


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## Slomo051 (Mar 3, 2014)

SPLEclipse said:


> Superb install skills. Next time you do a build take some pictures and post it to the Build Log section here, I'm sure we'd all like to see them.


Thanks for the vote of confidence. I did take some pictures from frame construction till final paint. I will post them soon.


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## Slomo051 (Mar 3, 2014)

MoparMike said:


> Well, seeing as how the SA line of subs prefers ported and you built the box to ported dimensions.......why not port the box? Making some alterations and adding some aero-ports wouldn't be all that tough and it would increase the output of those subs.


I considered adding some ports however, I know nothing about tuning, how many ports, etc. I found/used a calculator and for a 3" aero it was something like 9" long and unfortunately, the box won't accommodate that without hitting the speaker or cut into the frame due to the shape I had to maintain for space. Not to mention I have no clue where to install a port other than the sides. I hear if you tune it wrong, it turns into garbage. My ears are open for suggestions...would love to get more performance from these SA's. It hits hard but lacks low end.


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