[BC] The XLR pinout debate (Symmetra-Peak)

[Jeffrey Kopp]

I've enjoyed this discussion on polarity and learned a lot. It explained why an older microphone given to me was out of phase with my newer Japanese ones and I had to rewire its plug.

While I had realized consistent phasing of mics and speakers was important, it hadn't occurred to me that an overall phase inversion (end-to-end, even if all inputs or channels are consistent with each other) might not sound right to sensitive ears (though the experience of the announcer hearing her own voice inverted in her 'phones makes obvious sense).

Photo of a Symmetra-Peak (already sold on eBay): http://cgi.ebay.com/Kahn-Symmetra-Peak-AM-Transmitter-Audio-Processor_W0QQitemZ110005007943QQihZ001QQcategoryZ4671QQrdZ1QQcmdZViewItem

Looking for a schematic, I found it is Patent 3060389 (Oct. 1962, Kahn) which is apparently not on-line; it is referred to in a subsequent patent (and shown only as a block): http://www.freepatentsonline.com/4295106.html

A ham's design for a "phase rotating asymmetry eliminator": http://www.w3am.com/8poleapf.html

I wonder whether an asymmetrical signal "biased" in a digital editor to provide nearer-equal peaks would sound more or less distorted than the output of a phase-rotating processor. (Or perhaps this is indeed the current method, I wouldn't know.)