Hi Mickey, I didnt mention summing to mono because I wanted to get
across the basic idea first. 

 Also, there can be problems adjusting azimuth in mono on certain
stereo recordings. Say a musical piece has a strings backing which was
initially recorded as a mono track but in mixing to give a fake stereo
effect the producer has slightly delayed say the left side of the
strings re the right. It sounds OK in stereo but summed to mono the
strings now partially cancel out, sounding distant and indistinct. If
we adjust azimuth for the clearest string sound, we  now have the
wrong azimuth for other sources such as the important centralised
vocal.  In that case the vocal is the azimuth reference. The strings
are still out of phase but that's how they were meant to sound. 

Less common is a stereo tape recorded with a head with gap scatter.
One head gap is slightly behind the other in time. I have some  high
speed duplicated music cassettes with this issue. Correct azimuth
summed to mono resulted in incorrect azimuth (lost highs) in stereo.
So  I adjusted azimuth only stereo and for maximum clarity. Then to
correct the time differential I moved the delayed track slightly
forward to match the other. I did this in the DAW, realigning the high
frequencies in the waveforms by eye. 

Cheers Tim.     

----- Original Message -----
From: "Association for Recorded Sound Discussion List"
<[log in to unmask]>
To:<[log in to unmask]>
Cc:
Sent:Wed, 21 Oct 2020 15:12:02 -0700
Subject:Re: [ARSCLIST] Delayed Channels on Cassette Tapes

 Chris-Another tool is to combine the tracks while listening.Making it
mono. 
 The azimuth setting is most easily fine-tuned that way--Mickey

 -----Original Message----- 
 From: Tim Gillett
 Sent: Wednesday, October 21, 2020 2:47 PM
 To: [log in to unmask]
 Subject: Re: [ARSCLIST] Delayed Channels on Cassette Tapes

 Hi Chris,

 I'm not sure if you know that cassettes are notorious for azimuth
 misalignment on playback. Experts in tape digitization align the
 tape replay head to the recorded patterns on each tape being played.
 It involves carefully adjusting the azimuth screw on the machine's
 playback head while listening. We aim to extract the brightest,
 clearest sound off the tape. After this has been done, an Azimuth
 Corrector tool might be also used to fine tune the small remaining
 misalignments, especially dynamically changing misalignments which
 occur too quickly to be corrected by adjusting the head's azimuth
 screw.

 An Azimuth Corrector is generally not very good on a true stereo
 recording as it can struggle to distinguish between intended and
 unintended inter channel delays.

 Cheers Tim.

 ----- Original Message -----
 From: "Association for Recorded Sound Discussion List"
 <[log in to unmask]>
 To:<[log in to unmask]>
 Cc:
 Sent:Wed, 21 Oct 2020 13:34:11 +0100
 Subject:[ARSCLIST] Delayed Channels on Cassette Tapes

 We are digitising some cassette tapes using Audacity.. A batch of
 them
 are stereo, however they have exaggerated separation of the channels
 (perhaps they need normalisation?), and one channel is a microsecond
 behind the other. We don't actually need stereo, amd have tried to
 merge the channels into mono. But this sounds dreadful - the speech
 part sounds OK, but the music is very 'echo-ie).

 Another batch have delays from one channel to the other measuring in
 seconds. How can we time-shift one channel to match the other one?

 Thanks - Chris B.

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