Wanting help with an ABC sub box

**FyreDaug** · 07-13-2005, 05:04 PM

I want to build a box for my single 12" Type R sub. The box I built before is good, built to spec and tuned to 45 but I wanna go with an ABC box. For those who dont know what ABC is, its having 2 seperate tunes, and I want to tune for 35 and 50 hz and run the sub up to 65 (instead of tuned at 45 and running 50) So instead of having 1 spike where its tuned to, you get 2 and more of a flat response inbetween. Right now, my box doesnt like the lows. Ive heard this sub in a different box hit them lower harder, so I know its capable of doing it. Just want to drop the low to 35 and the rock freq's to 50.

The problem is, I have never built an ABC box and I dont know where to start with some information. How does the inside dimensions of an ABC box compare to a regular box? Does it change because of the 2 chambers?

Anyone have a typical layout of an ABC box I can work from? Ive got a guy that works installing into cars that can help me out. He's got the mdf and all the tools needed.

Any help would be appreciated.

**MSIGuy** · 07-14-2005, 06:00 AM

Well, wouldn't recoment an ABC box. It sounds more like if you built another ported box and tuned lower say 32-35Hz you'd be much happier.

If you're dead set on a different alignment I'd recomend a "snailshell". Basicly its a modified Transmission Line enclouser. Do a google search and you'll find quite a lot of information on them.

**MrPerfectionest** · 07-14-2005, 09:22 AM

For starters, we are talking about a bandpass box here, so lets please call it that from this point forward. Secondly, you probably don't have the equipment or the know how at this point to measure the theile-small parameters of the driver. Assuming you could get these accurate, AND assuming you are smart enough to use a program to do the calculating for you, you will probably botch the construction job as it isn't easy at all.

The bandpass in a car is really useless. Don't bother with a transmission line either.

All you need is a bigger ported box tuned lower and you might need a sub-sonic filter to keep your sub from unloading between the tuning frequency. I am not familiar with your driver (the Type R), there is a chance it isn't properly suited for a ported enclosure, you need to check this first. It's relatively easy with the correct 12 to get a tuning frequency down as low as 25hz in a not too horribly large box.

**MSIGuy** · 07-15-2005, 04:47 AM

Originally Posted by MrPerfectionest

For starters, we are talking about a bandpass box here, so lets please call it that from this point forward.

Well, for starters ABC is a type of bandpass, Aperiodic Bi-Chambered, to be exact, so the name fits.

Originally Posted by MrPerfectionest

The bandpass in a car is really useless.

A bandpass in a car is not useless. A properly designed one is really a great thing. Some of the leading SPL competitors are getting great numbers with 6th order bandpasses.

Originally Posted by MrPerfectionest

Don't bother with a transmission line either.

Again, when properly designed they're great. I challenge you to get the same output and the flat response from a regular ported box.

Just thought I'd clear some things up.

**markuskj** · 07-15-2005, 05:10 AM

LOL @ MrPerfectionest - why not leave the negativity out of it and put on the encouragement hat today buddy? It was surely unnecessary to tell this guy what he cannot do?

Tottaly agree with MSI there, I have seen many of these built and the results are usually very effective. There was a masterbuilder on the Talk Audio forum who made these very sweetly.

Yes more difficult than a simple box but who want simple!!