Determination of L/R channel sample offset - PCM audio (1 or more sample offset)

I have several albums ripped from CD, where one or more tracks suffer from an L/R channel sample offset of 1 or more samples. This can be visualized in Audacity, see photos. The posted file is mono and it is evident that there is an offset of 1 sample present. The 2nd image displays the start of the file after correction (the samples between L/R are now aligned by sliding channel R to the right).

For stereo files suffering from this offset, the visual inspection is more difficult. Is there any experience with a method to use software to check the files for sample misalignments without inspecting them visually, e.g. increased/decreased high frequency content? Thanks!

If this bothers you (I doubt it’s audible) you can kill one channel and make a true mono file (which will play through both speakers). The true-mono file will also be correctly “flagged” as mono when you look at the file properties. And if you save it as WAV it will be half the size. (It won’t make a difference with compressed formats because the compression algorithms are “smart enough” not to duplicate the data in a “dual mono” file.)

CDs are always 2-channels but if you re-burn the CD your burning application will probably accept the mono file and duplicate it.

It usually takes at least 10ms before you start to hear the sound dominating from the speaker where it comes-out first.

With stereo, of course the left & right channels are supposed to be different and if you align the zero-crossings at one place they’ll be “dis-aligned” at another.

Hi, thanks for your reply.

you are correct, the problem (if it is an actual problem) is easily solved by killing one channel and end with a true-mono file.

For test purpose, I have tried listening to a few mono tracks, misaligned and aligned over headphones. Listening to the misaligned file I detect a slight smearing of the higher frequencies, e.g. cymbals, and a sense of the signal not being entirely centered. Listening to the “fixed”/aligned file, the smearing is gone and the sound is dead center.

I am fully aware of my non-scientific approach to this matter. Maybe the channel misalignment is a rare occurrence of a mastering bug from the CD format’s early days.