I would suggest that there is no such thing as 2 IDENTICAL turntables systems. First, no two cartridges of the same model are absolutely identical - there are minor variations from unit to unit even in very expensive cartridges. Second, when you factor in the precision in cartridge installation and alignment that would be required to produce two IDENTICAL turntable/arm/cartridge samples, you are in never-never land. I would suggest that it probably can't be done. Let's also remember that the two groove walls of a monaural record are rarely absolutely identical, and that also goes for the two channels of any stereo cartridge. Anyone who has used a mono-mix or canting control on an archival preamp knows this to be true. By the early 1970s, most disc mastering facilities were cutting reissues of mono recordings using stereo cutters, because it was a nuisance to keep two sets of cutting equipment on hand, properly maintained. This almost ensures that the two groove walls will not be identical.
We are, to put it politely, blowing in the wind.
Audio Engineer Emeritus
The Crane School of Music
SUNY at Potsdam, NY 13676
"Great art presupposes the alert mind of the educated listener."
"A true artist doesn't want to be admired, he wants to be believed."
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Sent: Monday, December 21, 2020 6:36 PM
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Subject: [EXTERNAL] Re: [ARSCLIST] Noise reduction on mono records using two separate coherent sources
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So my humble idea FWIW would be to have 2 identical turntables, same tonearm, cart and stylus, TF, etc. both driven by a common source; some sort of servo controller that would output identical power, timing, locking, etc. to both tables. You’ve now theoretically got rid of most of those variations and you’re left with just the disc anomalies. They don’t necessarily need to be run exactly simultaneously, but the time base would be common and sync could be corrected (?). If I have the idea correct, this is different from the cake platter concept.
Others seem to be suggesting a sort of M/S processing which, even if successful on one disc, I would never even bother attempting with 2 copies.