Well, I'm using the Parts Express #295-130 15" driver with a #300-794 amp. This amp has an EQ section that can be adjusted if you require REALLY deep bass, but you probably won't need to mess with it.

I like a 3.75 cubic foot box with a 7 7/8" long 3" round vent. Add plenty of internal braces, and it should work out to something in the neighborhood of a 21" cube, assuming 3/4" material. Alternatively you can use a 4" round vent 15.25 long or an 11x1 slot 14.825" long. The model suggests the 3" vent could have a problem with excessive vent air velocity at low frequencies (23Hz or so) and high output, but just barely. I went with a slot, but that was more due to other considerations. Add a _light_ amount of damping material and you'll be in business.

Unless you get exotic with the cabinet finish you should be able to fit a pair of these within your budget pretty easy. Plus you can add more later if you feel a need.

If you adjust the EQ section I suggest Fx ~ 23Hz and Qx ~ 1.7

Instructions are with the amp, but some soldering will be required.

Each sub should be capable of about 114db @ 50Hz in free air, better in a room. Max output drops almost linearly from 114db@50Hz to 108db@20Hz (roughly) which seems to work fine for me. Note that the output limitation from 50Hz down is a driver limitation, so getting a bigger amp won't help.

If you have computer modeling software take a look at the model. It's not bad.


Charlie

I was wondering if I get the other amp, http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Product_ID=9389&CATID=43 will their a big difference in sound because of the amp being class D while the other amp is a A/B amp? I was also thinking of about using an svs s700 amp to power my sub as well.

Chris

Well, the digital amp will run cooler, but personally I'd go with the smaller amp - here's why - I want deep bass. From 20Hz - 50Hz the smaller amp can drive this cone into nonlinearity, so a bigger amp is a waste of my money. I'm better off putting that cash into buying a second, third, etc. sub.

If you want the max SPL from 50Hz up a bigger amp will help there, but for my requirements it was wasted $$$.

Also, I never downloaded the specs for the big amp, so I can't be sure it has EQ available, if you are considering that as an option.


Charlie


PS - The drop from 50Hz to 20Hz isn't a droop in frequency response, it is in maximium acoustic output - different thing.

[This message has been edited by charlie (edited February 18, 2002).]

Do you use a plate amp if you make your own sub? Or can you use something like an SVS A700 subwoofer amp. Also I heard the best value for sheer power to a sub and still being in a good price is to use professional amplifiers. I can't decide if to go with the SVS S700 http://www.svsubwoofers.com/samsons700.htm , or to go with a plate amp http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Product_ID=9389&CATID=43 , or should I go with something like a professional amplifier, something like a Crown CE1000 http://www.partsexpress.com/pe/showdetl...._ID=44451&DID=7 .
If you do not like any of these amps then I wonder if you could suggest your own amp to power a sub. Note this will be a large subwoofer, either a 15 or a 18inch subwoofer.

Thanks for the help,

Chris

Hey TheNotSoNewGuy,

If you have $600 for budget and some time and woodshop skills on your hand, I would seriously recommend taking a look at the Dual 10" NHT Subwoofer kit from Madisound. It includes the build drawings ( you need your own cabinet) and they're offering everything else for a cool $375 bucks. That includes 2 NHT 10" Woofers and the Controller and everything else that's needed like the tube and filling, etc.

Amp selection depends on lots of factors, but if you're using a plate amp (making a powered sub) there is a point where bigger stops being better.

I fiddled with lots of models when I was working out the above design, and while I'm not claiming it's the ultimate design it does perform very well for the $$$ for my requirements. I needed (wanted really) a system that could output 120db SPL 20Hz - 20kHz. The bass end in my HT is handled by eight of these bass sections and it seems to work fine.

If I wasn't interested in deep bass (maybe I listened to mostly pop and rock music?) then really deep bass would be less critical - max output 50 - 70 Hz might take more priority.

NHT has a good rep - I bet it's a nice sub.

The design I outlined above is pretty flat, tight and deep. It isn't super efficient, but watts are CHEAP!

Charlie

Take a look at www.audioc.com
They got some DIY speaker kits! I'd go with these.

Look at ACI's reviews on audioreview.com

Have Fun!

Chris,

At $600, you have a pretty large budget for building your own sub. Since you can build your own enclosures, your going to be saving even more.

You may want to consider some of the other subs Parts Express carries, like the Titanics or the Peerless XLS line. The 15" DVC is a good driver also, and should provide a ton of output. Even in a sealed box it should give you lots of lowend slam, especially when you figure in room gain. You should also consider Blueprint subs - www.blueprintdrivers.com. They get a lot of hype for being a good deal for your money. The "03" series is supposed to be insane, but you need lots of power to really take advantage of them (1000+Watts, for example). Of course, you could just use multiple of the "01" or "02" series drivers. www.stryke.com and www.adireaudio.com both carry some good sub drivers as well.

As far as amps go, I'd personally shy away from the class D amp at PE. I've heard rumors that they aren't worth the money. I'd stick with the class A/B amps. They are about half the price ($129 right now), and are supposed to have good power. You may also want to check out www.apexjr.com, and www.madisound.com. They both carry other lines of sub amps. I think Dave Craig at www.artofsound.net has some higher end amps he could sell you. They aren't on the page, but they are supposed to be quite a cut above the average amp. Adire also has some higher powered amps. Ideally, you could use a pro sound amp and an active crossover, but that's definitely going to cost you more.

I'd probably recommend that you go with the 15" DVC and the 250W A/B amp from Parts Express. If you wanted to blow all $600, get two amps and two drivers!

Good luck
Jason