I thank all of you for being so concerned that I'm destroying the UB/lower-MR drivers of my 5As by using a hi-pass filter point (HPFP) lower than 100Hz. But if that were to happen, my speakers would have been ruined many months ago. In fact, they aren't; they still sound excellent and maybe better than ever.
'Tis a fact that there's virtually nothing in this crazy hobby that's black or white, ESPECIALLY the results of very-'slow'-slope first-order filters. Do youz guyz really think that a...say...1- or 2dB difference in energy at...say...70Hz is going to ruin a driver in one of these systems? The overall volume a system is driven to has FAR more affect on the energy getting to a driver than the frequency of the HPF.
And how about the highly 'nominal' input-impepedance specs of some amps? My McCormack DNA-750s use transformers at the inputs to reverse the signal polarity going to one section of the amp. The amp's stated input impedance is 10K, but the actual impedance for CR filtering is 16.7K, measured very carefully and repeated. THAT difference would move the calculated HPFP 2/3 ovtave!
So calm your indignation, boys. My HPFP that turned out to be 58Hz is working excellently with my 5As, bringing with it a slight increase in overall warmth and richness without any 'thickness' in the lower frequencies, and I also run the bassamp controls lower than if I were using a 100Hz HPFP.
Youz guyz ought to be paying more attention to the head-banging, screaming-and-crashing dideeboppers who ARE overdriving their bass and MR drivers, not me.
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:-)
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