Eminence Beta 12" as subs?

[J. L.]

Originally Posted by kristyon

Wow, that is impressive. I never expected to get anywhere close to that. What kind of setup do you have that gives that kind of output? I don't expect I'll be able to match it until my kids have moved out and have no hair left lol!

Actually, I've since replaced that small sub with something more capable...

The driver that made that frequency response in my prior post is no longer manufactured, but it is a Adire Tempest 15" driver. It was in a 260L ported sonotube enclosure. The port was a piece of 6" diameter cardboard tube, somewhere around 24 inches long, tuned to just below 17Hz.

some specs on the Adire Tempest 15" driver:
Parameters
Nom: 2 x 8 Ohm, Power: 750 W, Fs: 18.8 Hz, Qms: 6.7, Qes: 0.4, Qts: 0.39, Vas: 317L, Sd: 779 cm^2, Xmax: 16.4mm, Re: 3.5 Ohms, Le: 2.9 mH, BL: 14.2, Mms: 195 grams, SPL: 89.1 dB @ 1W, 1m

The parts-express Dayton DVC 15" subwoofer is considered to be a clone of the Adire Tempest. (manufactured in the same factory) Dayton Audio DVC385-88 15" DVC Series Subwoofer 295-190

You can see the actual sub that made that frequency response here (260L tuned to just under 17Hz) :
HTGuide Forum - View Single Post - DIY Subwoofer Showcase
but... it was replaced a few years later with this pair of sealed 18" 12.5 cubic-foot subs built into the stage below my screen:
HTGuide Forum - View Single Post - DIY Subwoofer Showcase

Old (small) 15" Adire Tempest sub displaced 2.6L.
New (larger) subwoofers each have a 18" Ascendent Audio Avalanche driver with dual 2 ohm coils, wired in series for a 4 ohm load to the amplifier. Each driver has 6.5L displacement and is down-firing (Total displacement is 13 Liters) I had to weatherstrip the closet doors in the room even with the smaller sub... the doors would rattle in the frames otherwise.

I guess what I'm trying to point out is that home-theater bass in movies is very different than the needs of PA and music. Take a look at the spectrum graphs here:
War Of The Worlds (2005) - Home Theater Forum and Systems - HomeTheaterShack.com There is a ton of content below 30 Hz a PA driver cannot begin to reproduce,
even in kids movies: Finding Nemo - Home Theater Forum and Systems - HomeTheaterShack.com

(The 15" tempest driver seems to sell for between $100 and $125 in used-audio ads) The Dayton DVC is about the same new.

The 18" Ascendent Audio Avalanche drivers are unfortunately also out of production. They were much more expensive, but still under $300 on sale.

Last year I built four of the bass-sticks designed by J Bell. Good to only about 45Hz, but they are for ballroom dance music... and have 8" MCM woofers that were under $30 each. Again, great for PA use and music, not anywhere near as good for home-theater use.

Whatever your budget, watch this forum for ideas. You can find bargain drivers at almost any price level. You basically want a strong motor and as much displacement as you can get. When reproducing loud, low frequencies in movies, there is no replacement for displacement. (large xmax, large BL)

If you are going to the trouble of building something, at least target some decent performance. Perhaps you can sell the PA drivers and use the proceeds for a true subwoofer driver. Whatever you do, making sawdust can be a lot of fun.

Oh yes.. I have no kids... and very little hair, and I love to get immersed in a movie, to where I instinctively reach for the arm-rests on the chair when something un-expected happens to blow up on screen.

Joe L.