Subwoofer Setup for SPL Competition

tinmanchris217 · Feb 28, 2009

Build Up Pics for all.

tinmanchris217 · Feb 28, 2009

With the woofers in, and in the trunk pics.

tinmanchris217 · Feb 28, 2009

follow-up commentary - box is bigger than I thought, but the woofers have just enough surface area to send the sound to the port. Port volume is about 1 cubic foot. Internal volume is 5 cubic feet (2.5 for each woofer). Overall, I think it will work wonderfully when I'm done tuning.

Currently, the woofers are wired in series-parallel, to 4 ohms, which maxes out the amplifier (500w rms total, or 125 w per voice coil). The setup can handle nearly 4 times the wattage, and will eventually. I have a list of amplifiers that will work, but I need a cheap, good quality one.

Does anyone have any experience with:

- PowerBass ASA 1500.1d - ~$280
375w RMS @ 4 ohms, 750 @ 2 ohms, 1500 @ 1 ohm (3000w max)

- Hifonics bxi1610d - ~$260
550, 1000, 1600

- US Amps Merlin.2 MD-2D - ~$??
550, 1000, 1500

- Power Acoustik BAMF-2000/1d - ~$170
600, 900, 1200 (2000 max)

- Fusion Powerplant AM200010 - ~$260
600, 900, 1000 (2000 max)

- Pioneer Premier PRS-d1200SPL - ~$400
500, 1000, 1200 (2400 max)

I know that the PowerBass, US Amps, and Pioneer will under-rate their power, and that PowerAcoustik drastically over-rates, while Fusion, and Hifonics are pretty accurate.

If anyone else has suggestions in this range, or experience, feel free to drop a comment. Thanks guys.

paradigmsk8er · Mar 1, 2009

i have heard good things about powerbass at the pricepoint, and US amps isnt what it used to be but still good.

Just remember either way its more pressure on your electrical system.

let me know the results

tinmanchris217 · Mar 2, 2009

The system is bangin, to say the least. For daily listenining, I have the amp on the lowest setting. When the amp is 50% it, rattles the back door and the port, which I'm sure is losing a couple dB's.

Compared to a new amp, I think cash is better spent on a Voltmeter/Decibel meter.... I'm looking at the Audio Control Epic-160, which will tell you both the volts on your battery, and the dB at the dash. I realize it isn't perfect, but being able to keep track of my battery's condition is important, so I don't drain it, blasting at a stop-light.

Anyone have experience with the Epic-160 or 150? .... they seem accurate, and extremely helpful for my setup with a stock alternator.

otterpopjunkie · Mar 5, 2009

hey tinmanchris217,
first let me say that box looks pretty stinkin' sweet. nice job.

I see you already knew what's what with the constructive interference and such. I was thinking that a sub angled towards the front would provide the highest pressure at the dash, versus one blasting up would lose some energy moving the roof. (Although that's my goal

) Inside of a car is far from simple though. Do you remove the rear seats during the comp?

Corrupt_File · Mar 5, 2009

Boxes look good. I had a ported box, but it was a bit to boomy for me. I designed and built this sealed box. I designed it for the optimal volume for each speaker (there's a baffle seperating the chambers) and it sounds incredible. Did I get lucky with designing it?

tinmanchris217 · Mar 6, 2009

That box looks great! Are those MTX Thunder 5500's? Me likey.

You didn't just get lucky, those woofers (as many do) perform well in small/medium sealed enclosures. The shape of the box had just enough openness at the top to let the bass flow freely. I imagine it was a fine box, as long as your door was properly damped.

So riddle me this, how did you manage to get the back door from rattling like crazy?

I see expanding foam, dynamat, and no rear panel. I assume this took some work, but what seemed to fix the problem (rank the successfulness of each)

Corrupt_File · Mar 6, 2009

Thanks. They are mzs1204 12" subs. The Thunder's replaced them I think. They are the best bang for the buck by far (Each speaker was $30 new in box).

The expanding foam was the biggest factor in dampening the rattle. I dynamat'd the license plate as well. I tried to dynamat the rear door to prevent the panel from rattling, but it didn't help, so I just said forget it, and removed the panel. For ranking, the foam and rear panel I'd say were 50/50, the dynamat didn't help any (expect for the plate).

tinmanchris217 · Mar 6, 2009

gracias. Add Great Stuff to the Home Depot list.

Corrupt_File · Mar 6, 2009

Haha. Now that you mention it, it was a Home Depot Job. Got the 3/4" mdf there, 2 cans of expanding foam, and weatherproof outdoor carpeting (it was the closest colour match, and cheap).

paradigmsk8er · Mar 6, 2009

i will only warn you once..but be very..very...very careful using expanding foam in door panels..it will go places you did NOT intend if its not taped off (and sometimes even when it is) and can completely ruin your day for many reasons. It is a valuable tool but be weary. Also remember typically it is very flammable so keep it away from electrical connections.

A combo of eggcrate style foam, peel/seel or other damping, and expanding foam can work wonders if used correctly.

Remember damping materials such as peel/seel dynamat etc stop vibrations and insulate by adding WEIGHT to panels...some panels just have too much flex.

JonRav4 · Mar 6, 2009

paradigmsk8er said:
i will only warn you once..but be very..very...very careful using expanding foam in door panels..it will go places you did NOT intend if its not taped off (and sometimes even when it is) and can completely ruin your day for many reasons. It is a valuable tool but be weary.

I tried it many years ago in a different vehicle. I didn't like it. It expanded all over, filled drain holes, and didn't seem to add much sound insulation. If you want something fluid, check out Spectrum, or Spectrum Sludge at http://www.secondskinaudio.com/ These products do much more than just add weight, like roofing tar. They absorb vibrations/acoustics. They are designed for cars, not houses.

tinmanchris217 · Mar 7, 2009

I've been reading up on Peel and Seal... you can get it dirt cheap from Lowe's, etc. Great find, Paradigm.

Butyl is better damping for the weight, but per dollar, Peel and Seal can't be beat.

$15 for 12 sq feet. I might go pick up 3 or 4 and go to town. 2 layers should be enough to kill most vibration. Stuffing the the inside with a rubber foam sheet would be nice too, for plastic vibrations.

Corrupt_File · Mar 7, 2009

The foam I used was the soft expanding, it doesn't harden like a rock. This works much better for dampening compared to the hard stuff. The foam made a huge difference the sound, as well as reducing rattles. Those subs are only a few inches from that back door, so there is not alot of air dampening... you need something. The foam is kept away from the wiring loom in the door jamb... what else is it going to do? The product is only flammable when it is being applied, after it cures, its stable.

tinmanchris217 · Mar 8, 2009

Went to Lowe's, got some Peel and Seal. It's in the roofing area, in 3 sizes, 4", 6" and 9". I got 2 rolls of the 9" for $12 each

The product is basically aluminum foil with a tar/asphalt adhesive. Sadly, not too different from Dynamat, except the stickiness of this stuff is the asphalt... not an adhesive.

I popped off the back door panel and the upper plastic piece that covers the windows sill. Then unrolled 6 ~3' lengths (width of the plastic door panel). This came out perfect for 2 full layers. The whole process took about an hour and a half, and that includes the trimming, flattening, cutting holes for wires and panel clips... and for putting the panels back on. Its a nice project for anyone interested.

Don't know about results yet, but I imagine it will help reduce vibrations dramatically.

paradigmsk8er · Mar 9, 2009

I think you'll notice some solid results. the adhesive stuck fine even down here in FL heat for me. It should make the doors close more solid with a "thunk" and help with resonations and road noise, as well as random vibrations

tinmanchris217 · Mar 11, 2009

To accompany the damping for the car, I'm beefing up the box.

After about 200 watts, the box began to rattle. I've added screws so that they are every 6", and I have cut out most of the pieces for my new bracing.

Here is a sketch of the setup. It was a quick sketchup job, and I didn't get it clean or accurate, but the idea is still there. Its basically a 3 story building.

There will be three rows of 3/4" x 3/4" x ?? pieces on wood. The first is more than 3" behind the woofer, to minimize turbulence in the box. If this works out, then I'll pony up for some AllThread (threaded rod) and run it in the same places. AllThread is more aerodynamic and stronger.

Chris

tinmanchris217 · Apr 17, 2009

Sorry for the lack of updates recently.

I got the bracing done. I used about 80 more screws and a whole bottle of Gorilla wood glue.

Mission successful.

The box doesn't rattle in the least. It simply eats up the whole 800w RMS that the old Lanzar amp can put out. It's time for a new amp! :lol: Oh Boy!

I should be hitting numbers near the 142-145 dB range with ~1500w RMS on them. With about 300w RMS, the woofers really open up. As many pros have recommended, woofers operate best from 20% - 80% of their power range.

At 800w RMS, they are still clean and tight. The box is designed to minimize impedance and use all the properties of the woofer to bleed every dB out, but atleast at these power levels, they aren't breaking a sweat.

Don't get me wrong, there is plenty of room for improvement, but for now, I couldn't be more pleased. Thanks to all that helped with the project.

Pics will come, since the bracing was rather extensive.

Chris

tinmanchris217 · Apr 19, 2009

The goal was to minimize turbulence in the box, while adding lots of strength. The best way I found was to have only 1 cross member in the path of the air, everything converging to a point in the middle 6" behind the woofers, to minimize turbulence.

Enjoi!

Subwoofer Setup for SPL Competition

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JonRav4

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