I'm with Steve on this - I've neither seen (measured with a microscope) nor heard (validated by ear) a 1 mil groove ("microgroove") on a 16-inch transcription disc.
16-inch grooves generally range from 2.1 to 3.0 mil, the bulk being 2.3, 2.5 or 2.8 mil.
The 12-inch home recordings can be a bit narrower, where occasionally I've seen 1.8 mil. But that's the very narrowest I've ever encountered, and still not in microgroove territory.
Dictation discs like the Gray Autograph or Edison Voicewriter will run 0.85 to 0.90 mil. These are best played with a microgroove stylus or something a bit smaller.
Eric Jacobs
The Audio Archive, Inc. tel: 408.221.2128 fax: 408.549.9867 mailto:EricJ@xxxxxxxxxxxxxxxxxxx
-----Original Message----- From: Association for Recorded Sound Discussion List [mailto:ARSCLIST@xxxxxxx]On Behalf Of Steven Smolian Sent: Wednesday, September 05, 2007 5:51 PM To: ARSCLIST@xxxxxxxxxxxx Subject: Re: [ARSCLIST] 16" transcription player on ebay
I'be never seen a non-experimental 16" 33 that used a 1 mil groove- always a 2.5 mil, though I own a couple cut at 1 mil by Mirko Paneko in the later 40s.
I visited him in Stamford, I believe it was, a few times. He claimed to be the inventor of the LP and that Goldmark instigated the paperwork. Mirko died before I could persue this in any depth.
His name is now widely forgotten, but in his day he was well known for making audio systems for the rich, musical and famous, Toscanini being among that number.
Steve Smolian