I am interested in building a 2-way sealed box speaker based on the Jordan JX92S to handle 100Hz to 20kHz, combined with a woofer to handle 30-100Hz.
However, most of the woofers I have seen have very low Q fundamental resonances, typically in the range 0.2 to 0.4. This would be fine for a reflex or TL enclosure, but I want to use sealed box, so really need a higher Q in the range 0.5 to 0.7.
Does anyone know of suitable units ?
Other preferred requirements would be :-
8, 10 or 12" dia.
88 to 90dB/W/m
100W power handling
However, most of the woofers I have seen have very low Q fundamental resonances, typically in the range 0.2 to 0.4. This would be fine for a reflex or TL enclosure, but I want to use sealed box, so really need a higher Q in the range 0.5 to 0.7.
Does anyone know of suitable units ?
Other preferred requirements would be :-
8, 10 or 12" dia.
88 to 90dB/W/m
100W power handling
/sreten.sreten said:
Yes, I realise that, which is precisely my point.
If I want to achieve a flat and extended LF response, I need an overall system Q of between 0.5 and 0.7. But if I am starting with a woofer with a Qts of say 0.3, the necessary box loading (to flatten the response) would raise the overall system fs unacceptably.
So, the woofer Qts needs to be much closer to my overall target Q to begin with (or alternatively it needs a very much lower fs, of around 15Hz).
cs said:
Hi your conclusions are correct, as per your critia of vented designs being ruled out.
As I see it, your 30Hz -3dB spec , is the difficulty and severely limits the availability for drivers used in sealed woofer designs.
IMO your choices are
1) Use Infinite baffle design.
2) Acoustic suspension box with higher cutoff. If you could settle for around 45 Hz -3dB this would open up choices for drivers.
3) Use a Linkwitz transform circuit with a variation of option 2).
Found a good one from Scanspeak :-
http://www.tymphany.com/datasheet/printview.php?id=106
fs=20.5Hz
Qts=0.47
Vas=46 litres
Putting this into the MJK closed box worksheet gives system fs=30Hz and system Q=0.707, for a 1.25 cu. ft. box.
Not cheap at >£200 however !
http://www.tymphany.com/datasheet/printview.php?id=106
fs=20.5Hz
Qts=0.47
Vas=46 litres
Putting this into the MJK closed box worksheet gives system fs=30Hz and system Q=0.707, for a 1.25 cu. ft. box.
Not cheap at >£200 however !
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