This would depend in part as to whether the varispeed is constant across
the length of the tape, or if it varies. It would also depend on how
much it varies.
In general, I prefer to maintain a constant speed for playback, but if
the subsequent files need substantial alterations to get them back to
"normal" playing speed, then the digital artifacts can become extremely
annoying (especially if stretching instead of compressing the length)
I have had to deal with some tapes that were recorded on battery
operated equipment where the speed has varied by more than 20%, due to
the batteries going dead during recording. This required some rather
severe varispeed correction (beyond the range of what most standard
professional machines can do). In general, I have favored doing gross
speed corrections in the analog domain, and final tweaking in the
In some cases, we have made one pass at constant speed, and another with
In any event, any corrections should be noted as part of the subsequent
This is just my individual approach to the issue. To the best of my
knowledge, there is no "standard" best practice for this.
Scott D. Smith CAS
Chicago Audio Works, Inc.
On 3/2/2020 4:58 PM, Parker Fishel wrote:
> Hi ARSC listers,
> We have some 2” session tapes that we are currently getting digitized. We
> encountered some varispeed reels and are trying to figure out how to
> properly transfer them for preservation purposes. What are the best
> practices? I did a little digging around, but haven’t been able to come up
> with much.
> Thanks in advance.
> Kind regards,
> Parker Fishel