Need advice on SPL build.

[ItsAJeepThing 10+ year member]

My friend and I have been working on an spl build to take to a competition coming up. We have an Audiopipe 30001D with a 15" FI BTL. Its in a 93' mazda mx-3. The box is 5 cubes tuned at 45hz. The car peaks at 50hz. The box has 45 degree bracing's in each corner. We have 1/0 running from the battery to a distro block, then 4 gauge to an optima red top then 4 gauge to amp. We are replacing the speaker wire with either 10 or 8 gauge. We also have been told to paint the inside of the box and silicone it. The amp was run at 2 ohms and we are considering doing a half ohm burp. The length from distro block to battery is about 3 feet then another 3 feet to the amp so theres about 6 feet of four gauge. The box will be wrapped in duck tape also. We hooked it up to a termlab today and got a 146.5 in the kick panel with driver door open and sunroof open. when everything was sealed we did around a 143.8.

Questions:

Will the audiopipe handle a .5ohm burp?

Wiring the sub to .5ohm isnt a problem but how would we plug the wires into the audiopipe?

Is there anything else we can do to gain db's?

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[basscort2009 5,000+ posts]

Don't do .5 it will blow ur amp

Fiberglass resin the inside of the box everywhere

Upgrade all power and ground to 1/0

^^^ that's good for at least 1.5 dbs all together

 

[stevew007 10+ year member]

if you have a meter get testing anything and everything. seat placment,mic placment,try towels under the seats,close the heater vents duct tape them if you can,seal all holes every where, deaden the hell out of anything that the sub or port loads off of, deaden the passenger door, make sure all the door seals are in great shape,upgrade wire, make sure when you test that the battery is at the same voltage every time,make sure you log everything and make a check list. in my crx if the box moved 2" i lost a 1db sitting on my hatch was 1.2db there is a ton of crap you can test with a temlab in hand

 

[ItsAJeepThing 10+ year member]

Would we have the electrical to back an audiopipe 1500 @ .5?

 

[stevew007 10+ year member]

Would we have the electrical to back an audiopipe 1500 @ .5?

its not the electrical its the amp! you can try it whats the worse that can happen? blow the amp? maybe it wont pop maybe you have enough box rise for a good burp.I've never messed with audiopipe so i have no idea what im talking about LOL

 

[sacsking916 5,000+ posts]

why do you have a distro before your battery? why not just use your battery as a distro?

 

[elancohen92 10+ year member]

why duct tape the box? i know nothing of this spl but i plan on it soon

 

[hispls 5,000+ posts]

That's a terrible number for a 15" off of 3000W. Would like to see pics of this box (the way it sits in the trunk and such)

If you can measure impedence of the box at your burp freq you may be able to run that amp at .5 ohm nominal, but if it isn't rising up to 2 you're likely to break the amp regardless of the voltage you have to it.

I have a friend that used to do a lot of DB Drag and he said he gained for every run of 1/0 gauge wire he ran from his battery back to the amp (he ended up with 10 runs and apparently gained for each).

 

[slim2fattycake 10+ year member]

Check to see what your rise is at that frequency you use. If you're rise is enough to keep the ap3k over 1.33 ohms then you should be fine. Just have battery power to back it up. How much room is there to move the box around and change firing directions? You need to do that as well.

 

[stevew007 10+ year member]

why duct tape the box? i know nothing of this spl but i plan on it soon

the smoother the better. a guy gained about 1db just by taping the back of his seats so the air would flow easier

That's a terrible number for a 15" off of 3000W. Would like to see pics of this box (the way it sits in the trunk and such)
If you can measure impedence of the box at your burp freq you may be able to run that amp at .5 ohm nominal, but if it isn't rising up to 2 you're likely to break the amp regardless of the voltage you have to it.

I have a friend that used to do a lot of DB Drag and he said he gained for every run of 1/0 gauge wire he ran from his battery back to the amp (he ended up with 10 runs and apparently gained for each).

in a class where you are only allowed 1 battery in stock location 10 runs of wire is key but when you have a battery 3ft from the amp you should only need 4 runs

 

[ItsAJeepThing 10+ year member]

We duct tape the box because it seals the outside, mdf is porous. Our local car audio shop said they gained db's when they wrapped in duct tape. We clamped the amp the same day and got a huge impedence rise, about to 5ohms. Thats why I thought it would be ok to go to .5ohm because the amp would never really see it. The box has no room to move. Our next box will be smaller so we can experiment with firing direction.

 

[Rudy 10+ year member]

if you have a meter get testing anything and everything. seat placment,mic placment,try towels under the seats,close the heater vents duct tape them if you can,seal all holes every where, deaden the hell out of anything that the sub or port loads off of, deaden the passenger door, make sure all the door seals are in great shape,upgrade wire, make sure when you test that the battery is at the same voltage every time,make sure you log everything and make a check list. in my crx if the box moved 2" i lost a 1db sitting on my hatch was 1.2db there is a ton of crap you can test with a temlab in hand

That's a lot of good and logical advice. The only thing I'll take issue with is the use of deadener (vibration damper). You've rightly pointed out how important it is to seal air leaks. In most cases when applying vibration damper improves things, it's because it sealed some leaks.

What you really want to do is stiffen the panels. Vibration damper is a pretty ineffective way to do it. Vibration damper stiffens the panel slightly but has an offsetting mechanism that can hurt you - it works by converting vibration - which can become sound, into heat - which can't. These factors combined explain why adding vibration damper sometimes produces a slight improvement, sometimes a slight loss and sometimes no change at all. Seal the leaks and find ways to make the panels rigid and you can be confident that all of your efforts are moving things in the right direction.

 

[stevew007 10+ year member]

That's a lot of good and logical advice. The only thing I'll take issue with is the use of deadener (vibration damper). You've rightly pointed out how important it is to seal air leaks. In most cases when applying vibration damper improves things, it's because it sealed some leaks.
What you really want to do is stiffen the panels. Vibration damper is a pretty ineffective way to do it. Vibration damper stiffens the panel slightly but has an offsetting mechanism that can hurt you - it works by converting vibration - which can become sound, into heat - which can't. These factors combined explain why adding vibration damper sometimes produces a slight improvement, sometimes a slight loss and sometimes no change at all. Seal the leaks and find ways to make the panels rigid and you can be confident that all of your efforts are moving things in the right direction.

well in most orgs there are lists of products that can be used.so using dyno,fat,peel and seal, just makes sense if he is trying for a lower class and not extreme or super mod. when doing deadener its best to test it every time. in my current vehicle i placed my hands on the roof (not pushing) just a dead weight and i lost 1 db from it so no mat is ever going on there. but as for my doors i used 2 layers of peel and seal behind the super small door panel huge difference in sound when closing the door. i didnt test the doors because i wanted them done regardless.

 

[stevew007 10+ year member]

We duct tape the box because it seals the outside, mdf is porous. Our local car audio shop said they gained db's when they wrapped in duct tape. We clamped the amp the same day and got a huge impedence rise, about to 5ohms. Thats why I thought it would be ok to go to .5ohm because the amp would never really see it. The box has no room to move. Our next box will be smaller so we can experiment with firing direction.

yeah i dont think mdf is pourus. why would you seal the box on the outside when all the pressure comes from the inside?it would just blow the tape right off now if this were true you would want to seal it from the inside so it could not blow the tape off right?

 

[05fronty 5,000+ posts]

deaden everything you can. also the vents in the back of the vehicle( i guess it is what that is), take them out and put a piece of thick plexiglass over them. they were on the back wall in each corner of my frontier