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Hi John

Hi John, I am middlin along, my health has stabilized, but my time is all but consumed by my employer (trying to get the work of THREE engineers out of me, working like TWO wasn't enough!).

How are you doing?

You wrote:
"Didn't you post this link back in 2007?

Actually, I did, but since then, I have had a chance to see higher resolution copies of the graphs (my computer back in 2007 just did not have the resolution to see the small GIF's very well), and I was able to take them and create color-coded overlays and ANALYZE the multitone distortion products a bit more closely, and see what was going on in terms of WHERE the distortion was coming from.

I plugged the multitones from Voishvillo's paper's (reference 3 & 4) into my spreadsheet, and looked a the various orders of the highest level distortion products, and where they came from.

I have satisfied myself that they were NOT measurement artifacts, or overload of the passive crossover magnetics (a distinct possibility given the crest factor), primarily because the patterns are similar between the full-range two way with passive crossover vs. the raw subwoofer, and the orders suggested by the distortion products look like loudspeaker back EMF issues I have seen before in my own measurements.

Thus, I wanted to call attention to them once again, with people much more likely to pay attention to Dr. Alexander Voishvillo than little ole' me.

You wrote:
"What they really should have done was replace the passively crossed over drivers with resistive loads, that way the gap permeability vs frequency and velocity could have been eliminated as the difference.

Naw, with load resistors on a passive crossover circuit, what mostly shows up is crossover overload, which is interesting, but academic in terms of looking for cable distortion.

As an interesting aside, when I experimented with some power amps that BREAK the feedback loop from being influenced by the loudspeaker back EMF, most of the big sonic differences between cables goes down, as does a low level grundge that always seems to be present to one extent or another with most conventional feedback amps, even with my mostly load invariant Stax DA-80 pure class A power amps. It seems the speaker cables are much more a part of the SYSTEM than anyone ever imagined.



Jon Risch


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