As the heading says, I have a pair of Martin Logan Monoliths, the bass driver is a so so Eminence built for ML for this speaker, I would love to get something better, this is what is has to do.
Attached is the specs for the Eminence, if they are correct.
Box size sealed 85liters
Crossover is 125hz 2nd order 12db per octave
The goal is to be -3@30hz but to have clean out put to 400hz
I've looked at
Peerless XXLS 830847
Focal 12V726
Focal 12v726S
I'm sure there are many others
Thanks George
Attached is the specs for the Eminence, if they are correct.
Box size sealed 85liters
Crossover is 125hz 2nd order 12db per octave
The goal is to be -3@30hz but to have clean out put to 400hz
I've looked at
Peerless XXLS 830847
Focal 12V726
Focal 12v726S
I'm sure there are many others
Thanks George
Attachments
Hi,
The most important parameter is to match the 92dB sensitivity.
I think most of the high excursion 12"s are lower than this.
Also finding a 12" driver suited to 85L sealed box loading is
not going to be easy, by the time you do its likely to be very
similar to the Eminence in its capabilities (due to the 92db/W).
Possibly you need to factor in a plate amplifier with a 2nd
order L/R roll-off and remove the passive croosover, would
then let you use a very serious 12" unit which has much
lower sensitivity than 92dB/2.83V/1m.
/sreten.
The most important parameter is to match the 92dB sensitivity.
I think most of the high excursion 12"s are lower than this.
Also finding a 12" driver suited to 85L sealed box loading is
not going to be easy, by the time you do its likely to be very
similar to the Eminence in its capabilities (due to the 92db/W).
Possibly you need to factor in a plate amplifier with a 2nd
order L/R roll-off and remove the passive croosover, would
then let you use a very serious 12" unit which has much
lower sensitivity than 92dB/2.83V/1m.
/sreten.
Ok i've found two drivers that may be ok, what do you guys think, I ran them through a program for the 85liter (3cuft) sealed box, remember it's crossing over to ELS pannels at 125hz at 12db per octave and this is what i got.
Focal 12V726:
-7db at 30hz
QTC of .69
mms of the Focal is 55 gram so it should be ok up high 200-400hz
The ACI SV12:
_4db at 30hz
QTC .78
mms of the ACI is 100 grams, could be too heavy for 200-400hz.
Which way guys? I'm not very experienced with this driver parameters voodoo, I'm more into the electronics side of things.
Cheers George
Focal 12V726:
-7db at 30hz
QTC of .69
mms of the Focal is 55 gram so it should be ok up high 200-400hz
The ACI SV12:
_4db at 30hz
QTC .78
mms of the ACI is 100 grams, could be too heavy for 200-400hz.
Which way guys? I'm not very experienced with this driver parameters voodoo, I'm more into the electronics side of things.
Cheers George
If you need 12" with efficient od 92-93 dB, passive x-over, go for Monacor SPH-315. Bass-reflex 72-80 L netto, Fb=36-37 Hz.
Monacor SPH-315
Monacor SPH-315
It will be very tough if not impossible to get a perfect fit. With that in mind, my recommendation for a drop in would be the HiVi M12 http://www.swanspeaker.com/product/htm/view.asp?id=84
Though more of a vented woofer, IMHO it would work just fine in a sealed 70-85L enclosure, Qtc around 0.5, F3 65hz (anechoic), which with room gain, should make -3db 30hz somewhat realistic, YMMV.
cheers,
AJ
Though more of a vented woofer, IMHO it would work just fine in a sealed 70-85L enclosure, Qtc around 0.5, F3 65hz (anechoic), which with room gain, should make -3db 30hz somewhat realistic, YMMV.
cheers,
AJ
Thanks all you guys for helping, but it seems as all recomeded driver so far have something that makes me feel there must be something better out there. This is the one so far that has my attention it's the old ACI SV12, it's mmd seems low enough at 93 so can anyone run it through their good speaker program and let me know how it fairs.
85lts
no stuffing qtc and -3db point
100% stuffed qtc and -3db point.
Here are the only specs I can find on this driver
Cheers George
85lts
no stuffing qtc and -3db point
100% stuffed qtc and -3db point.
Here are the only specs I can find on this driver
Cheers George
georgehifi said:
Hi,
I don't understand your concern with mmd, it tells you nothing
about the effective linear bandwidth of the driver, for a given
sensitivity of a 12" driver, the higher mmd is the lower the bass
you will get, if excursion capability is the same, the higher mmd
driver simply needs a bigger magnet.
green = eminence, yellow = contender (95L to account for stuffing)
/sreten.Attachments
sreten, Yes my concern with the mmd stems from discusions with Neville Thiele here in Epping Sydney along time ago (25 years) when he helped me build a pair of 12cu ft vented sub enclosures for a pair of Kef B1814 oval bass drivers, F3 for memory was 16hz
I remember vaguely him saying that usualy the higher the mmd figure you may see a ragged roll off of a frequency graph in the highs of a bass unit where given the similar parameters a driver with a lower mmd usualy rolls off with a smoother trace thus having lower muddy distortion/cone breakup.
This is why I was asking, as it was 25 years ago and I wasn't sure about it, the last thing I want is to have a distorted bass roll off into the clean overlap of an electostatic lower mids
Cheers George
I remember vaguely him saying that usualy the higher the mmd figure you may see a ragged roll off of a frequency graph in the highs of a bass unit where given the similar parameters a driver with a lower mmd usualy rolls off with a smoother trace thus having lower muddy distortion/cone breakup.
This is why I was asking, as it was 25 years ago and I wasn't sure about it, the last thing I want is to have a distorted bass roll off into the clean overlap of an electostatic lower mids
Cheers George
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