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vernb
05-28-2008, 07:59 AM
Can anyone link me to a place where I can find suggestions for a x-over to use in a 2-way speaker with the JBL 2445 driver? I have tried without luck.
My 2445 are 8 ohm drivers and I have a pair of Smithhorns 2397 lying around.
I have a pair of 075 alnicos aswell, but there doesn't seem to be much point in adding them, since the 2445 go higher up.

I haven't decided on the woofers yet. They will be one 15" or two 12" drivers per speaker.

Thanks
Verner

hjames
05-28-2008, 08:29 AM
Can anyone link me to a place where I can find suggestions for a x-over to use in a 2-way speaker with the JBL 2445 driver? I have tried without luck.
My 2445 are 8 ohm drivers and I have a pair of Smithhorns 2397 lying around.
I have a pair of 075 alnicos aswell, but there doesn't seem to be much point in adding them, since the 2445 go higher up.

I haven't decided on the woofers yet. They will be one 15" or two 12" drivers per speaker.

Thanks
Verner

Have you considered using an active crossover like the Ashley or JBL M552 and biamping the system? That way you can just set it as you need and it leaves open the possibility of experimenting with different drivers.

grumpy
05-28-2008, 09:05 AM
active split does simplify experimentation if you have the gear :)

800Hz or higher (JBL recommended for 2397)
12dB/octave or greater slope (protect the diaphragm)
... think you still might want a tweeter eventually, as just the
switch to 2446 diaphragms is noticeable in regard to HF energy.

2-12" drivers and ~1KHz xover in a 2.5-way system ? (sounds vaguely familiar ;))

matching horn pattern w/ a single 15" might be a challenge.

vernb
05-28-2008, 09:06 AM
Thanks Heather, for your quick reply. I would rather make my own passive crossover, and also as I have understood, even if going active I need a passive x-over to compensate for the roll-off of the compression driver.

I have an active filter for the woofer, that I could use at 720hz.

grumpy
05-28-2008, 09:09 AM
...compensate for the roll-off of the compression driver.Hmm... 2440 response on 2397 (see 2397 pdf file) looks 'compensated'
already to me, much like a radial horn. ... perhaps showing my ignorance :)

Edit: ...or perhaps some wishful thinking on the part of the marketing dept.

a less "biased" measurement using 2441/2397:

http://www.audioheritage.org/vbulletin/showthread.php?t=3849

I personally would be inclined to let the 244x rolloff (perhaps adding some
encouragement) and add a tweeter to taste, as opposed to shelving the mid-band
to EQ-up the treble range.