On Sun, 31 Aug 2014 12:34:12 +0200, George Brock-Nannestad 
<[log in to unmask]> wrote:

>However, let me state once and for all: there is no reason to believe in
>accidental stereo, unless we have an absolutely stable timebase in both
>channels, and identical at that. If you take any two mechanical recordings 
>the identical performance, even via the same mike feed, you will inevitably
>obtain spaciousness due to flutter in one or both channels, which by 
>ears is interpreted as stereo. 

I've been out of town for a few days and am just getting around to 
commenting on this thread.  The issue George brings up has always been the 
sticking point with regard to the acceptance of accidental stereo from the 
very beginning.  When it comes to synchronizing discs whose matrices were 
originally cut on two different tables, there are so many variables -- 
differing original recording speeds between the discs; pitch fluctuations 
within each disc; playback speed variations; incorrect centering of the 
records to be played back; disc warpage, etc. -- that it becomes difficult 
if not impossible to determine whether the differences were due to separate 
miking or inexact synchronization.

The difference in the recent Pristine release that Andrew Rose and I worked 
on from prior efforts was that for the first time, Capstan was used to 
ensure that the two sources were played back at exactly the same pitch, and 
any differences due to centering, warpage or pitch fluctuations were 
automatically straightened out.  Coupled with the use of phase-locking 
software for synchronization, we can finally hear what these matched sides 
really sound like when joined up.  

On the page devoted to this release on the Pristine website,

you can hear examples of a 1929 Stokowski "Carnival of the Animals" side 
and the complete third movement of a 1930 Tchaikovsky "Pathetique" Symphony 
under Koussevitzky, along with essays on the methods used for these 
reconstructions.  (The second half of the Koussevitzky example was only 
available in mono, and you can hear the difference accidental stereo makes 
once it disappears.)

Just as we were able to prove the existence of accidental stereo for some 
sides, we were able to use the same methodology to disprove it in other 
recordings which had previously been accepted as stereo.  For example, we 
considered including the two 1941 Stokowski/All-American Youth Orchestra 
sides that had been released as accidental stereo on Cala ("Ride of the 
Valkyries" and the Scherzo from "A Midsummer Night's Dream"), but found 
that once properly synchronized, they were only out-of-phase mono.  The 
same thing happened with Side 4 of Koussevitzky's "Pathetique" which Brad 
Kay had previously synched up.  While it was issued in takes marked 1 and 
1A, the two were in fact identical, even to the amount of lead-in 
revolutions, meaning that one of them had been mislabeled.

As one ARSC member put it to me, this new methodology has finally made the 
process "much more based on 'science' instead of 'art'".  I invite you to 
listen and draw your own conclusions.

Mark Obert-Thorn