spl gereral questions from a spl noob...

[5K Mobile Electronics]

I've been in the business for the past 12 years, I've done my fair share of big builds.., but I've been roaming the SMD forums for the past week and checking out some of the builds going on here. I see one reoccurring theme(besides the big subs, lol), layer upon layer of mdf and 2.4's for the walls. I've never done a spl build, so seeing all those layers is completely new to me. One of my questions is, is there actually a noticeable gain in output from building them that way? Vs maybe using 1" MDF well braced internally? I've always been the type of installer who thought I should build everything so if this guy decides the get rid of the car/truck, we can yank it all back out and put it back to stock with minimum hassle, but after seeing some of the builds on here, I'm thinking of picking up a car to do one of these crazy spl perma-builds in. They've got me pretty curious. Another question was about the wiring, I've seen multiple alternators, but haven't really seen multiple 0awg's ran to the back, there's the possibility that I overlooked that part in some installs.

[STEvil]

There can be big gains when its done right, but when you go overboard with the mutli-layer baffle its not doing anything. About 3 layers of 1" is usually enough for a wall, assuming you add a bit of internal bracing too. Maybe 4 layers if you're doing a 4x18 or something more..

As to the multiple 4/0 2/0 1/0 0/0 etc runs, yeah you've missed them. They're there. Some people go a little overkill with them though, and i've seen a lot of them improperly insulated (read my sig).

[Freshman6969]

using trippi's hummer as an example, ric used i think 2 or 3 layers of 3/4 or 1" thick wood, not mdf, pine is alot more light weight and alot stronger and gives off better sound to some people, so ive heard at least, anyways that wall does not even vibrate what so ever even when playing low notes, that wall is build like a damn ROCK

[StrongmanDesigns]

The layers are usually done as a precaution for playing very loud and very low. With a high tuned spl build you could get away with thinner walls without having to worry as much about stuff breaking. But the newer trend is to reach very high pressure levels at very low frequencies which is extremely destructive.

[5K Mobile Electronics]

Thanks for the info guys, gives me some understanding about the layers, and now that you mention it, those low notes are pretty destructive, I ended up using fiberglass reinforcments inside the last big system I did because even with 1"mdf glued and screwed, it still managed to break apart the ports from the inside walls.

[n8ball2013]

spl builds? These are daily drivers in a lot of cases. lol

[HHR Ed]

I've been in the business for the past 12 years, I've done my fair share of big builds.., but I've been roaming the SMD forums for the past week and checking out some of the builds going on here. I see one reoccurring theme(besides the big subs, lol), layer upon layer of mdf and 2.4's for the walls. I've never done a spl build, so seeing all those layers is completely new to me. One of my questions is, is there actually a noticeable gain in output from building them that way? Vs maybe using 1" MDF well braced internally? I've always been the type of installer who thought I should build everything so if this guy decides the get rid of the car/truck, we can yank it all back out and put it back to stock with minimum hassle, but after seeing some of the builds on here, I'm thinking of picking up a car to do one of these crazy spl perma-builds in. They've got me pretty curious. Another question was about the wiring, I've seen multiple alternators, but haven't really seen multiple 0awg's ran to the back, there's the possibility that I overlooked that part in some installs.

Most of the builds on here are ground pounders and daily rides.

So for pure SPL the techniques are going to be slightly different.

Usually 2x4s are good for the ground pounders,

but

For SPL its better to weld in a steel cage using square steel tubes, and fill the tubes with a polyester resin/sand mix to reduce resonance.

Then using Birch (not MDF) or Oak is preferred. Multiple layers is used for strength, and density. You can even use steel plates sandwiching concrete.

But 4 layers of Birch on the sides, top and bottom work well.

For the baffle, usually 6-9 layers of .75" works the best. Not only for rigidity and density, but for acoustic purposes. It gives the port it's length and keeps some back pressure from building up on the rear of the woofer cones.

When all done right. In a Super Street car, these types of enclosures are good for 170+ dB if you can manage to ever get that high.

The other types with 2x4s you have been mentioning are 160 dB boxes.

[HHR Ed]

resin/sand/cement mix is for 170+ cars

[AMI CUSTOMS]

I have multiple runs of 0/1 in my daily driver. I only used 2 layers of 3/4 mdf, that it most cases is way more then enough strength. Some people on here kill trees using 2x4 for bracing, it is quite frankly a waste of wood. Sure 2x4's will brace, but there are far better ways to brace a ground pounder.

[audioanonymous]

Ed don't be telling everyone how to get loud. lol