Sound like familiar behavior? I bet it does. I am struggling with part of the band above 2,500 Hz in my Bozak speakers and although to others they sound fantastic, to me they sound off compared to the best systems in my sonic memory combined with what I know instruments really sound like. I am studying the issue and trying to decide how to put my concerns to rest. A week ago, after enough RTA measurements and enough analysis of the crossover network, I discovered a few things about the Bozak drivers that I overlooked in the past (yes, I too make mistakes).
The midrange driver has an aluminum dust cap along with its aluminum cone to improve dispersion and extend its bandwidth. It is this aluminum domed dust cap that is causing my distress and influencing the sound of the tweeters in their operating bandwidth. Rudy Bozak decided to use a first-order Butterworth crossover network to minimize phase issues and rightfully so. But the rising sound pressure after the crossover point indicates a mechanical resonance beyond the prresumed supression point that needs to be tackled if my ears are to be pacified.
I have two multimeters that read capacitance but none that read inductance, the two components used in passive crossover networks. So arriving in the mail last Friday was a new inductance meter and now I am set to redesign the Bozak network to suite my personal acoustic preferences. Hopefully over the next few months, I will succeed at this feat and tell you of my progress either good or bad, but with the holidays coinciding, the amount of time I have between getting my next book out and improving my system is VERY limited.
Yours for higher fidelity,
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Copyright © 2015 by Philip Rastocny. All rights reserved.