View Full Version : How to improve a pair of 4315A (crossover problem...) ?

CB Amp
08-05-2008, 02:03 PM

My first post on this forum, even if I often read the threads.

I've got a pair of 4315A, and one has a slightly lower level than the other (I've tried with several amps, preamps, cables...). I have to adjust with amp volumes and Xover settings.
I thought it could be a problem in the crossover network circuitry. Some friends told me it was a good thing to rebuilt JBL crossover networks with good quality components. They did it with good results, with Mundorf caps and coils, Hovland or Auricap, etc... Very expensive !!
What do you think about it ?

At last, if I build a new filter, would it be possible (and usefull...) to biamp 4315A speakers ? If so, I just have to divide the LF speaker from the 3 other ones, with the same filter circuitry ?

Or do I better have to find a pair of 4343 ?!?! I'm a bit disapointed by the lack of bass and definition of these speakers. Good ones, but...
I began with L112, then L65 and 4315, it would be a natural way !... ;)

Thanks for your help !

08-05-2008, 05:14 PM
Hi, welcome on this forum!

The A version of the 4315 uses alnico drivers that can demagnetize and loose a few dB when pushed hard. The T/S parameters are also modified.
Chances are that one of your speakers suffer from that. The lack of bass you describe also looks like a symptom. Does the less sensible speaker also seems less "punchy" that the other one?
In any case checking the magnet charge is always a good idea. If you are near Paris I can give you an address for that.

Network tweaks are another interesting improvement, you will find plenty of posts on that topic on the forum.
Their is also a topic about the 4315 in the System Information section, with a quote from Greg Timbers (the conceptor) that you might find interesting