What would happen if I put Sound Deadener inside my sub box? Cars rattle because of the resonance that occurs when panels are affected by sound waves. The sub box would obviously resonate somewhat, so if it had deadener inside it, would it sound better?

if you could get into the box you would find out quickly that you wouldnt last a minute with the pressure that is created by the sub, not to mention lack of air for you to breathe. Like i've said somewhere else, if you can hear what goes on inside a box your from another planet

SD inside the box is not neaded nor will it do anything major if the box is of the right thickness. You'd be better off spending money on SD for the car rather than the box.

Also is the box built to spec or is it an abouts to what is needed for the sub?

Also if correctly tuned and you dont listen to bass discs then you shouldnt get resonance...

^^ I'm with Mr Canada

Yeah, it was more of a hypothetical than a physical plan, but just thought I'd ask

Sound Deaden! No Need! However You Possibly May Get A Better Sound Out Of Your Subs If You Fibreglass Resin The Inside Of Your Box This Totaly Seals The Box And The Air Pushed Around The Inside Of The Box Is Not Absorbed By It. However Dnt Put The Subs Back In The Box Till The Resin Has Completely Cured I Put Them In To Early Once Ond ****ed A Pair Of Mtx Thunder 8000 Over $1000 Thanxs For Cumin.

hmmmm thats an interesting idea custom... I might give that a go

Trust Me The **** Works I Do This At Work All The Time With Cheap Boxes With Loose Fibre Mdf Youl Only Need 500ml Of Resin Per Single 12 Box Do It In Bout 3 Layers Let Each One Dry B4 The Next Put On. But Remember Let It Dry Youl **** Dacks If You Dnt And You Open Your Boot And See Ur Pride And Joy Warped And Wrinkled Like I Did.

dude why do you type with capitals at the front of every word? I saw it in another thread also...

*on topic*
I wouldn't bother sound deadening inside your box either, use it otherplaces on the car.

... (sorry nothing to add here)

can't believe no-one mentioned the fact there are reflective waves inside a box. There are a few products to counter these waves, such as Focal Plain Chant (Box of 8 $120RRP) or Dynamat Dynoxorb (RRP???). Having done it in a few boxes, i swear by it. Really the ideal enclosure will be spherical, it naturally cancels back wave distortion, but this is really impractical. Take the home speaker market into account. Nearly all the cut outs of boxes i have seen have some form of enclosure damping to reduce reflective waves inside the cabinet, that potentionally causes mudiness.
On the subject of enclosure shape, check out B&W's Nautilus speakers. The top of the mid-range enclosure is round and their flagship $250,000 speakers are based on a snail shell. To answer your question KickerCat, yes some form of enclosure damping will help. The sheet stuff won't help. If your on a budget try some fibreglass insulation bats (wear gloves, goggles and breathing mask when working with the stuff)

forgot to add...... capital letters are over rated.

I'd heard about the sphere being the best shape - so if you rounded off the corners of the inside of a sub box, would it improve the sound? Or how about creating a spherical enclosure? you could make a sphere out of fiberglass, put that inside an mdf box, and fill the gaps in the corners of the mdf box to stop the fiberglass cracking/flexing. Hmmmmmm...........

thats a darn good question. I have seen it done in a comp car in the States. He blew up a beach ball to the correct volume and fibreglassed it with an mdf ring on the front for the baffle. Then he deflated the ball when the resin was hard and pulled it out. About 5 of 6 layers of chopped matt was added, fibreglass re-inforced filler then bondo the sanded and painted. They do look like giant boobs in his boot though.

If you make the enclosure strong enough, it wont crack. Bit much effort if you ask me, so just dampen the inside of the box you have and presto tight accurate bass!