I wanted a sub that could: integrate with the non-bose stock audio system; conform to the interior; really rock at 1000W; be inexpensive; be removed if I should ever want to sell or trade for a new vett. I’m thinking out of the box here………..soooo my solution is-why not put everything in the box? Some of you audiophiles might cringe at this idea, but hearing is believing……..and this box rocks.


This is the interface: Sub output level control, mini phono plug + jack (signal in), and the remote power on via PL259 connector.

Amp power is thru 60 amp removable glass fuse + 8AWG wire from battery


This is the power connection thru base of enclosure, turned on its side


The inside view—enclosure has a hinged hood for access to amp for tuning + maintenance.


Here you can see the Sony XM-SD61 1400W amp, dual Pioneer TSW2501 10in subs
Weatherstripping and silicon was used for the sealed enclosure.


I used the ADD-GM24 interface on the HU. Had to add two 10uf capacitors to the low-level signal outputs for DC blocking. With the 10K ohm input impedance, they act like a high pass filter- passing all frequencies above 2 Hz.


System can be disconnected and removed in minutes, about 30 lbs, cost about $600 and sounds great, no vibration, rattles or booming…..just good, clean solid bass. What do you think of my concept/prototype?

 

why would u be running a highpassed filter on a signal to a sub

 

I hope you have that box bolted to the car by at least 6 big bolts. Even then, I'd say its got a pretty good chance of killing you in even a mild car accident.

 

Thanks for the insight Kale, I have not overlooked safety.
Structural safety is being considered. I also am concerned about heat buildup. Don't want a raging fire behind the driver.
That's why it's still a concept/prototype.

 

heat buildup could lead to premature amp failure as well.
Quick question, how do you bolt down the hinged lid?

for as much as an amp weighs, why not perminately mount the amp and make the box removable?

 

do caps have the same effect on low level outputs? I actually never heard of anyone putting the caps there. Also, why use a highpass for at 2hz?

 

It also looks like you took the 12V Positive from the feed to the underhood fuse panel. i would be concerned about the additional draw on the feed supplying the fuse panel. The additional amps may cause a problem.

I would get the 12V's directly from the battery.

 

Perhaps a pair of large straps to hold it down.... there's nothing quite like beind in a collision AND being nailed in the back of the head with a flaming subwoofer box.

the "in box" idea of the amps is questionable for over heating. What you could do is open the box, build a partition to seperate the subs and amp, then use in/out fans to keep the amp cool while leaving your subs with a sealed enclosure.

you might also want to look into matching carpet.

 

he's got a good idea. jl audio had a similar setup for the 93-96 mazda rx-7. Maybe look at that design for inspiration
Also, is that box too large for those subs? since they are shallow subs I'd look into taking advantage of that and make a shorter box.

 

that much weight could easily snap a simple strap. I can't think of any safe way to secure that, because the gas tank is under. Just screwing into the car's body won't do it. Sure, that might keep it from sliding around - But get into an accident and that sub box is going to be going through your front windshield... barely impeded by your braincase.

Well... If you installed a roll bar in the car, and attached it to that, you would probably be fine.

 

I was referring to a Cargo strap (rated at 5000-10000 lbs) You could mount one side of the strap to an anchorboard behind the seats and the other side somewhere in the cargo compartment with the ratchet or other locking device in between.

A friend and I are considering a similar design in his 72 coupe but it's more of a modified cargo tray with a single low profile 10" sub.

 

Ah, I get you now. I thought you meant the plumbing straps a lot of people were using to secure sub boxes.

Still, have to worry about mounting points. Car is fiberglass afterall.

 

Thanks for all the great input, people. It's good to know I've got you thinking about it!

I think the roll bar is a great idea, with an anti-glass net. Many racing equipment vendors sell an anti-submarine bar that bolts to the seat frame, somehow add a 2x4 to the sub-base with bolted eye-bolts for metal cable clips?

I had to use series capacitors because for some reason there is a DC voltage (5v) riding on the signal wires from the HU. The amp low-level input is protected from large voltages. When you connect a cap in series with the 10K ohm input impedance, you create a CR high pass filter. Calculating the -3db cutoff freq you get about 2Hz. The CR network blocks DC-2Hz, and passes 2Hz - 20kHz.

I can always move the power to battery terminal, but GM calls for jumper connections to the fusebox terminal. We're talking 200+ amps when jumping?

I wanted a self contained system, because if it works out, I can move the sub-system to my GMC Sonoma. But I might have to go with your advice, and piggy-back the sub amp onto the stock amp....if that's do-able.

On the lighter side of things, I suppose I could just prop the box up vertical in the passenger seat and strap her in

 

Wow...I can't say I've seen anything like that in a Vette before. I'm all about improving the sound system, but I guess I prefer a little more stealth. Instead of having that humungous box, why can't you make one that covers the complete floor about 8 inches tall or so? In fact, I think a Vendor now makes something similiar...at the very least, it would be safer and not a target for theives.

 

Thanks Hank!
I might try that, plenty of xtra MDF around. I would lose the portability, but would eliminate my safety problem.
The sealed enclosure meets all volume specs for the speakers, don't know how the flat enclosure would sound.

Back to the drawing board.

 

No problem buddy...I did a little research about that false floor idea. You can PM the guy about portability etc...follow the link: http://forums.corvetteforum.com/show...ht=false+floor

 

OK, the box design proved out technically, that wiring and components work well as a system and the sound is incredible. But the thought of a flying 40lb shell taking my head off is not appealing. I designed a new system, using the false floor approach. The 10" dual subs are in seperate, ported enclosures, with a volume of 0.6 cu. ft. each. The rear section will be walled, and the front is open air (amp) supported by evenly spaced pillars. Plan on cutting speaker holes in a cargo mat to cover entire floor. Also note, I have left room to access storage bins.

Before I start hacking and glueing, would like to get comments on this project. Thanks for your support.

 

looks good so far. The holes in the carpet for the speakers are a good idea. Make sure you leave about 1 inch of carpet hangover on the inside of the sub hole to give you a clean finished look.

About the cargo bins: I'm not too familier with the C6 cargo bins, but i've neve been able to get a false floor carpet and a cargo bin to look good together. If you have the space to do it, you may want to consider replacing your OEM cargo bin lids with MDF hinged or sliding doors that are bolted to the false floor.

Looking forward to more pics.

 

much better concept. i would personally center the amp (i'm a fan of symmetry). Just make sure to plan your cuts, you'll never get that board in there in one piece. if you want some more ideas you can check out some of my concepts and my final installation:
http://scott_fx.onfinite.com/album/1019181/1209119/
you can see how the false floor was broken out


and def check out this guy:
http://www.diymobileaudio.com/forum/...ad.php?t=30378
be sure to click on his link to his website in his sig and also look at his other posts on that forum.. he does some great work

 

What are the ports tuned to? assuming the image is accurate I'd estimate 70-80hz which is bad news. assuming they are 3x7 or so.

if each port was 3x25" that would give you a tuning of 34hz. Good SPL bump, but you'd want to use a subsonic filter.

that box is a prime candidate for slot porting (building a "maze" of walls)