BEAR Labs logo      THUNDER WOOFERS!  (v4.02)

This page shows both the type of modern woofers that are now available. Their application
in the Quadripole Subwoofer System yields outstanding results that could not be achieved
using earlier driver designs.

(Amongst the many suppliers of new motor/high Xmax drivers, this page shows the results with
just one of them. This particular driver was supplied by Adire. BEAR Labs has no business
relationship with Adire, nor is this an endorsement of Adire.)

This driver is typical of what is now available, the curves come next.  Wow!

Adire DPL-12 Rear View

Looks pretty nice... cast basket, dual gold plated spring loaded BPs... dual VCs...

Adire DPL-12 front

Big foam half roll, and a monster dustcap...

The Xmax is really substantial about 15mm! This means that the practical low frequency limit
at high output is extended as compared to earlier designs.

Here are the freq resp curves:

Quadripole test box at 10ft.
This is a single DPL12 installed in the 4cuft Quadripole test box, with PR. The driver has not yet really
been broken in fully. The response in this curve is room response at 10 ft, approximately listenting
height and listening position. The right hand cursor is at 47Hz, and the left is 19.6. You can see that
the whole thing is within 3dB from about 55Hz (there's a 4th order LP filter there) down to about
23Hz., with the left cursor point read out on the bottom at 4.5dB down from the max... not too
shabby. The intended application is to meet a speaker (and ESL in this case) as a SUB Woofer, not as
a full range Sub/Woofer - although this driver will work in that application (see curves below).

Here's the DPL-12 measured nearfield about 6" from the driver's dustcap, with the xover. This shows
the response of the driver ALONE, without the contribution of the PR. You can see the effect of the
xover and the effects of the loading in the box, while the PR's contribution is invisible from this mic
position. This is pretty much what one would expect to see here, since the PR starts loading the driver
and reducing its excursion as much as an octave up. The PR here is tuned to about 23Hz.

Quadripole nearfield no xover
This is the DPL-12 woofer without a crossover loaded into the Quadripole test box. The response is nicely
smooth out to 200 Hz and beyond. The mic position is nearfield, about 6" in front of the dustcap. As before,
droop below 50Hz. is due to the PR and box loading,and is expected. THis shows that the driver is
suitable for mating with full range ribbons (like the BG RD-75) and various mini monitors/mid bass drivers.

Please keep in mind that each channel uses TWO cabinets, so these results are known to be slightly less
in terms of LF output than the two cabinets together!!

With initial tests on program material, the box (which is around 75+ lbs alone) tipped over substantially
on big bass pulses! On Mickey Hart's DAFOS, cut 8 "Gates Of Dafos" the displacement was so great
that I had to put about 50 pounds more of weights on top of the cabinet to keep it flat on the floor!!
The full configuration should be rather awesome.