info on the JBL 2431H ?

[Tom Loizeaux]

Can anyone send me to info on the new JBL 2431H compression driver?
Is it available to us?

Thanks,

Tom

[Zilch]

Order through JBL Pro Parts. If that doesn't work, PM me.

I put some impedance sweeps in the "Quick & Dirty 4430's" thread:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=27&p=53943

There's plenty of RTA response curves there, too:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=24&p=50853

So far as I've been able to ascertain, the tech specs are "in house only," since these are not offered as component sales.

3" aluminum diaphragm with kapton surround, allegedly, resolving the longevity issues. Silpad throat gasket to transmit heat to metal horns. 1.5" throat exit. Neodymium magnet. New design phase plug pushes rolloff out to ~7 kHz, supposedly. Marginal below 1kHz with stock back cap. Easily "pushed" to 20 kHz, perhaps beyond.

We're on our own for now.

[They playin' "Red Hot & Blue" here presently.... ;) ]

[Dave Zan]

[Marginal below 1kHz with stock back cap][/QUOTE]

Anyone know what fraction of the compliance is from the rear air chamber in a typical compression driver?

I'd like to experiment with a more voluminous rear chamber but it's non trivial with a 2447 I believe - you can't just undo a few screws.
So if the compliance is dominated by the suspension then it's not worth the effort.
Obviously this varies from model to model. I know that the S9800 drivers have a different back chamber so presumably it makes some difference - the question is how much?