[78-L] Reversing audio (was: 78-L Digest, Vol 22, Issue 17, was Why I Hate LPs)

Jeff Lichtman jeff at swazoo.com
Mon Jul 12 11:19:56 PDT 2010

>We had a session at ARSC in New Orleans which demonstrated that
>reversing recordings digitally must NOT be done.  They demonstrated how
>a square wave turns into curicules and regular sound waves become almost
>unrecognizable in comparison to the original.  They might sound ok but
>they aren't.   Sound can be reversed in analogue with minimal problems,
>but even there you can run into an absolute-phase issue if you are not
>careful. But NEVER EVER reverse audio in the digital domain.
>Mike Biel   mbiel at mbiel.com

Am I misunderstanding something here? Reversing a digital signal 
introduces no distortion - all that happens is that the samples are 
put in the opposite order. I can understand that playing back an 
analog recording and then reversing it digitally might introduce 
distortion, but the distortion (if any) would happen during the 
reverse analog playback, not during the digital reversal.

You can test this yourself. Take any digital audio editor with any 
signal and reverse it twice, then compare it with the original. There 
will be no difference.

                        -        Jeff Lichtman
                                 jeff at swazoo.com
                                 Check out Swazoo Koolak's Web Jukebox at

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