there were 3 different speakers.
1st was the honeycomb made by sony?
2nd was a speaker made by Tonegen? screw in the magnet (bigger OD) these are in my silvers
3rd was ??? no screw in the magnet (smaller OD) these are in my plats.
when I say OD, I mean the basket at the point the metal spiders start there bend inward
my rotted one's measure 10-1/2 at the bend(11-7/8 OD - (11/16 x 2 flange's)= 10.5)
also I know this because I blew 2 woofers under warranty 1993, when I got the new woofers they had a plastic adapter ring to make the hole smaller, mine have the bigger hole, didn't understand what they where for till I got on this forum last year,
got this off the diyaudio forumhttp://www.diyaudio.com/forums/full-ran ... -high.html
I got that from the designer Jim Croft, who lives here in Seattle.
I created the Carver Amazing woofer system and Large Area Ribbon (co-authored
with David Graebener) for Bob Carver in the mid 1980's as a consultant to
Carver Corporation and was VP of Research and Development at Carver in the
1990s. I would be glad to answer any questions anyone has about these devices.
One question that was asked was whether the Amazings had a high or low Qms. The
Qms was quite high, we attempted to achieve a Qms of nearly 10, which is
required if one is going to end up with a Qt of much greater than 2 and still
maintain reasonable efficiency.
The trick is to be able to maintain 'linear' Qms. One of the big problems we
found early in the development of the Hi-Q open baffle was that many of the
Hi-Q drivers have Qms values that change depending on level. This non-linear
Qms causes a non-linear Qts, which causes a non-linear frequency response with
level...i.e. compression/distortion. This Qms modulation is one of the main
reasons that some have found higher Qts drivers to sound bad. It’s is not the
higher Qts, but the Qms -> Qts nonlinearity that causes the poor sound quality.
Proper Qts match to baffle cut-off frequency will perform quite perfectly, even
for higher Qt values if the resulting frequency response is flat and the Qt
value is maintained at all listening levels.
The Amazing suspension components, spider and surround, took nearly 9 months to
work through the design problems to chase out the non-linearities. No one had
optimized high-Q woofers previous to the Amazings so the driver vendors were
not able to help. We had to drive the component development ourselves. It was
hard to get spiders with low enough damping (they actually call them dampers in
Japan) to achieve high-Q and then it was even more difficult to develop spiders
and surrounds that maintained constant damping.
Okay, that is probably more than what anyone wanted to know on that subject,
but I felt it was important to start getting past this myth that “high-Q
drivers are bad”. It is a systems approach. High-Q is not inherently bad, but
‘mismatched’-Q is. A high-Q driver is appropriate when matched to a ‘low-Q
baffle’, just as a Low-Q driver is appropriate to match to a ‘high-Q’ Helmholtz
The original Amazings had even higher Qts and lower Fs than the later Series.
As someone in the forum suggested, lower Fs requires higher-Q, but this becomes
problematic. For a fixed baffle cutoff frequency, with the standard 6 dB/octave
high pass characteristic from cut-off down to the resonant frequency, the ideal
high-Q gain would match that first order slope over the bandwidth from cutoff
to fs. Unfortunately, the 12 dB of gain we needed in the original Amazings to
achieve reference level at the Fs of 20 Hz required a Qts of about 4. This
created a narrow band peak that doesn’t match the smooth, 6 dB roll-off slope
of the open baffle. Because of this we had to use some shaping networks to
smooth things out from 25 Hz to 100 Hz. We ended up with a fairly smooth
response with a peak at 20 Hz and Fc at 17 or 18 Hz.
The later Amazings had a new lower mass paper cone woofer to replace the
heavier honeycomb devices in the originals. We were able to get the moving mass
down to less than 15 grams, which is quite low for a 12” woofer, but required
for getting decent efficiency.
The Fs was raised to 30 Hz and the Qts was lowered to a value between 2.5 and
3. This worked much better in matching the Fs, Qts, and baffle Fc to get a
smoother response and much higher efficiency.
got a router??? a 45deg cutter may be all you need, this cutter would follow the existing hole.may give you the room you need