Subwoofer Kits

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I am something of a neophyte having completed only two projects some years ago. Now however is the time to dive back in and I am looking for a good subwoofer kit/plan. Definitely under $1000 and with a good SAF. Also, Bob Vila I am not, so availability of cabinets would be nice. It would have to seriously out perform the HSU VTF2 which is easly found for $450 and seems to be the deal in commerical subs.

Ideas? Suggestions? Resources?

If $1000 is your price range I'd highly reccomend building your own box (even if you're not Bob Vila). Because the box will take a big chunk out of your $1000 budget (especially if you want a sturdy well constructed large subwoofer box). Just get someone to help you build it, I'm sure you've got friends good at wood working...
Elk River Acoustics to the rescue!

Elk River Acoustics (my own little label) offers plans for a small-box 150-watt powered subwoofer, known as the BAM "American Thunder" subwoofer. All you need to be able to do is cut plywood or MDF, whichever you have access to. I use plywood myself. This subwoofer uses a 120-watt plate amplifier which is measured at 156 watts into 4 ohms, and a BluePrint Drivers model 1001 woofer. The actual box is no more than 14" wide, 20" deep, and 20" tall. Its design is tasteful and offers a whole host of paint/finishing options. The BPD1001 woofer has 24mm of P-P excursion (no wimpy specs), and the design has a F3 around 28 Hz. This makes a great small hideaway subwoofer that you can put in the corner or behind the couch, yet a subwoofer that packs enough punch for the marvelous digital bass effects in DVD movies. It also has the punch to take a small system and take it big. The entire project should only cost $110 of you go the plywood route. I don't know about MDF myself. I'm 16 years old, and very into this speaker building thing. I use WinISD, a computerized speaker designer, to design my projects and predict the outcomes. Let me know if you are interested. I should be building my box this weekend, if everything works out right.
Ah, its good to see a fellow 16 y/o audio enthusiast :) But anyways...

I built a subwoofer using Adire Audio's Shiva driver, a 16 inch diameter sonotube, and the AVA-250 amp, also from Adire. The total cost for the project was well under $500, and it beats the pants off most other subs I've heard. (Not quite up to the Krell Master reference or the Wilson, but you dont have 2k to spend on drivers alone, and neither do I for that matter :))

The Shiva is regarded as one of the best driver values on the market today. It is a 12 inch, kevlar reinforced paper driver, featuring dual voice coils, a good deal of excursion, and ample power handling. It can be purchased from

I tuned my sub to 16hz, and I couldn't be happier with the outcome. Its looks are quite similar to that of the SVS or Hsu subs, except that I made the endcaps gloss black to match the finish on my other speakers. It's tall, but sports a narrow footprint for good SAF, and because of its cylindrical design, it doesn't need nearly the amount of cabinet material of most other cubic or rectangular subs (a beautiful thing when you dont need 2 friends to help move it.) I strongly recommend the AVA-250 amp though, due to its built in active crossover, output levels, and most importantly, phase controls (this took a lot of toying with, but it now integrates seamlessly.)

I can give you further specifics of the design, but I found this site to be extremely useful:

Good luck on your project, and feel free to ask as many questions here as you see fit.
New sub project design approach?

All right. Now I am rollin… After a quick review of all those nifty TS params, and alignment types I think I’ll roll my own after all, and I might as well decide on the Shiva right now. Also looks like the software has improved since my last foray into DIY and besides, the real satisfaction comes from seeing your own design come to life and finding out how projected performance squares with reality. Anyhow, this leads me to several wide ranging questions….

If you can you design a passive radiator system the same frequency response as a ported box twice the volume why is it not a more popular approach? I realize the rolloff below fB is steep, but hey, if I can tune to the low 20s or below, who cares? I know, I know, the "flat to 15Hz or die trying" crowd may think that’s a crime against nature.

By the same token it seem like Isobaric offer similar advantages and them some, but I see even less DIY interest in this approach. With better transient response and a half size cabinet , seems like a natural as long as budget allows you to make up for the lower efficiency. What’s the downside? Are these always sealed or is a 4th order possible?? And has anyone incorporated push/pull with isobaric???

Here I go again with size…..I guess it does matter…. I noticed Dave Paton’s 1 cubic foot Shiva project. Immediately appealed to the boss and to me too - as a stereo pair! Can an EQ circuit really make these little guys sound BIG league? What about the sound quality?

There was a thread no so long ago about passive radiators. Rather than rehash the same ol' same ol' here, you might want to go browse through that one. In short, passive radiators add mass to the air in what would otherwise be a port, which slows response and makes the bass muddy. That's my view in a nutshell. You'll find other views in the thread, but note that there are no examples of high-end speakers using passive radiators, only mid-fi.
Isobaric is actually a pretty nifty idea, but keep in mind that you've doubled your driver budget before you even get out the door. Some people feel that if you're going to use two drivers, you might as well get all that potential cone area radiating into the room. Personally, I think the idea would be more popular if drivers were cheaper.
Electronic EQ of subs...been there, done that. I've built several subs on that principle over the years. Yes, they can go deep. What no one ever tells you is that you can't just work off of a simulated response curve and come up with a proper compensation curve to match it. You have to test and fit and fiddle quite a bit to get things to come out just right. Most people just take the circuit the program gives you and assume that the result will come out properly. Bad assumption. Anyway, the upshot is that the bass is indeed deep, but is muddy, as you're soon running the driver past its linear excursion. Cone excursion increases something like four times for every octave you drop. Since many people don't seem to have a clue what real bass sounds like, they're happy with the deep part. Of the three ideas, this one is the cheapest, excepting the fact that it also takes a gonzo amount of amplifer power to get down deep; that extra cone excursion doesn't happen for free.
There's been some discussion of Isobaric here, and I think at least two threads about sub EQ. The Linkwitz site has full plans for an EQ sub system, but the KEF B-139 he used is (unfortunately--both Geoff and I agree that KEF made some fine drivers, and the B-139 was one of the classics) no longer made.

Searched the threads for info on isobaric enclosures and found little depth. Likewise a web search turns up scant info.

I am intrigued with this design and would really like to pursue it. My general question involves the orientation of the drivers. From what little I've seen it
seems you have two options:

1.) face to face (gasket to gasket), wired out of phase, on a baffle inside the box with one chamber ported in a 4th order bandpass

2.) both facing the same direction, wired in-phase, with the front driver in a small sealed chamber radiating outside and a larger back chamber, likely sealed,
but possibly ported.

Just intuitively it seems like the second option would be preferable. Wouldn't the face to face config generate it's sound waves primarily on
the back stroke? . And wouldn't the speaker basket itself cause all sorts of turbulence/distortion?

Anyone have experience or ideas for additional resources?

many thanks
So here's the new concept: Two Shivas mounted clamshell isobaric, down firing, in a sealed 45 liter (1.59 cubic foot) box, with the AVA 250 amp.

My (naive) idea is to yield the mid-low .6 Q of a standard sealed 88 liter system, with good extension and superior musicality, in the smallest possible box.

Feasible? Pitfalls? Alternatives?

Any feedback highly appreciated - thanks
Velodyne CHT 12"driver vs. Adire Shiva 12" driver

What would be the better between these two drivers? Why? Well, I currently have the CHT-12 Velodyne series sub, but wanted to know if I'd gain subsonic performance if any by purchasing the Shiva 12" driver and installing it in the existing Velodyne encloser....any suggestions?? Thanks

[Edited by jmorriso on 12-04-2001 at 01:39 PM]
Probably Not

This is because of the servo module mounted on the actual cone of the driver to feed information about cone movement back to the control circuitry. However, building a new Shiva sub (not needing a servo because the Shiva is a very high-quality driver) seems like a good idea, or perhaps you might go for an Adire Brahma woofer.

Another reason putting the Shiva into the CHT's enclosure is that the enclosure more than likely does not have the proper internal volume for the Shiva.

I dunno, somebody else may have a better explanation than I do, but all signs point to not putting the Shiva in the Velodyne's enclosure.
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