A cheap 12 that might work

[mannthey]

I was surfing the great world wide web today and stumbled onto a closeout driver that maybe somone might be intrested in. It isn't an ideal driver but it is very cheap....

www.meniscusaudio.com/Specials/specialsdisplay.cfm

"Buy out from BG Corp. 12" woofer made by Eminence with Poly cone, foam edge and approx. 28oz mag. "high Q" woofer great for infinite baffle designs. Fs=21Hz, Qts=1.09, Vas=258L, Xmax=11mm, 8 ohm. Only $29.00 ea or 4 for $100 + shipping."

I know the Qts is high, xmax is only 11mm and is has a foam surround but for 25 bucks each and a fs of 21hz.....

I haven't seen any Eminence drivers like this before.
You could get alot of displacment for cheap if you are ok with the high Qts and driver build quality.

[ThomasW]

Interesting, one would need a few of them, but they'd be a good introductory tool...

[gottavtr]

The high Qts is good right? .707 is ideally flat, a little higher gives a slightly fuller sound that most people respond to. Over .9 may be a bit high but i would not think that it is as bad a .4! Would 4 of these not be sufficiant?

[dewardh]

Some people actually prefer the kind of flabby, muddy bass that a high (over .5) Qts produces (and many otherwise discriminating listners find Q up to .7 acceptable <g>), but for most music, or if you otherwise want to accurately reproduce the electrical signal delivered by the amplifier, a system Q of .5 or below is prefered. Very low Qts drivers are designed to enable a reasonably low overall Q in a sealed box . . . in an IB the Qts pretty much is the system Q.

A high Q indicates stored energy in the resonant system, resulting in continued acoustic output after the driving signal has passed. Low Q indicates less stored energy, or damping which dissipates stored energy, or both. The Qts figure is mostly concerned with how the speaker behaves near resonance, but the good damping indicated by a low Qts has favorable effect throughout the driver's entire range.

[ThomasW]

For quite sometime many considered the 'ideal' "Q" for dipole/IB driver to be 0.69. So even if that were accurate the Meniscus would be out of the park with their very high "Q"

The term used to characterize aligments always make me laugh. .707 is called optimally or maximally flat. And a "Q" of 0.5 is considered critically damped.

In the end this becomes a matter of what sonic characteristics you like. It's fairly easy to raise the "Q" of a driver, but it's impossible to lower the "Q". So my suggestion is start with a lower "Q" system. If you want a bit more 'bloom' raise the "Q" with EQ or by putting a resister in series with the driver.

[bilbobaggins]

Hey I bought four of these drivers. They are very lightweight compared to my Atlas 15's and Shivas. And shipping costs from Meniscus seem pretty reasonable to me too.

Based on lots of googling, I believe these woofers are the ones referred to by the ldsg

"Vendor guidelines - Other Eminence Built Drivers:

The Eminence-branded propreitary drivers listed are:

The Order #2601 "Eminence 10" home theater subwoofer" from Martin Sound have reportedly been used as subwoofers for Bohlender Graebener ribbon drivers with excellent results. This is an highly compliant driver with a black PP cone, rubber surround and a notably low value of Fs. response waterfall
NOTE: Although this is called a home theater driver, it is not magnetically shielded!



Order #2602 "Eminence 12" Hi-Fi Woofer" from Martin Sound. This is pretty much a "big brother" to the #2601 noted above. Many of the same comments apply. The caveat for this driver is its unusually high Qts, making it suitable primarily for open air mounting or use in TL enclosures."

ldsg.snippets.org/vendors/eminence.php3

I haven't listened to them yet but I am intending to use them for a set of two dipole woofers. For something inexpensive there isn't much risk to play around.