How to repair a stereo recording in Audacity

[soundalike]

I've got a few damaged recordings due to a faulty mic. The right channel comes in and out in places - probably because the connection to the right caplet had worked loose. I've got new mics now but what can I do with the damaged recording to make it 'stereo' again?

This is what it sounds like:

[attachmentid=1771]

Here's what the tracks look like in Audacity:

[attachmentid=1772]

And in more detail:

[attachmentid=1773]

I've tried to copy and paste from the left channel to the right to patch it up but it's really difficult to line it up to make it sound exactly right. Are there any shortcuts or easy ways to do this, or is it just a matter of patience and trial and error?

Cheers

Sample_Audio.mp3

[Skradgee]

All you can really do is duplicate the left channel to make a mono mix to fill in the silence in the right channel. It won't be true stereo of course, and you’d notice it when listening to the recording through headphones, but it'll sound better than leaving it the way it is.

One other thing you could do is create a fake stereo mix. There are certain effects you could apply (simulated stereo, 3D sound, etc.) that would make the transitions into the mono parts seem less abrupt or awkward. Ideally, you'd apply something like that to the entire track/mix since using that on only the mono parts could make the recording sound even more strange.

[m15a]

this seems pretty drastic. maybe 25% is lost? and there is popping and distortion on the edges of the "good" sections of the right channel. it seems like the best route would be to give up and just go with mono (copy the left over to the right completely). i didn't listen to the sample, but either the source doesn't need to be in stereo or if necessary, copying over the left to the right will result in something not acceptable.

if you want to try, maybe it'd help to use fading rather than just simple copying and pasting. (never tried it. just an uneducated guess.) on the other hand, maybe that cause more problems with the channels being out of phase. maybe you can try flipping the signal if the left and right are more out of phase than in phase. ::shrugs::

[soundalike]

Thanks for the suggestions. In highlighting the bad sections here I've probably made it look like the whole recording is like this. However the show was about an hour long and there are only two or three songs that have this fault, and of those only the one shown here has a lot of crackle and numerous episodes of signal loss. That's why I'm keen to patch it up rather than 'mess up' the whole show when the majority is perfectly ok. I have other shows where the right channel is completely missing so that one's a no-brainer.

Cheers

[m15a]

sorry. i misunderstood. also, if my idea of fading in and out the copy of the left channel doesn't work out right, maybe you can just try to make sure the ends of the sctions where you replace the right channel with the left have a lower volume, or are at least at zero crossover points. all of this is to prevent pops from the sudden change in the wave. actually, even if you do use fading, you'd still be better off looking for quiet segments to switch over. overall, i think it's the sudden changes you want to avoid.

[soundalike]

Cheers. 2 quick questions:

What does a zero crossover point look like?

What's the difference between fade in/out and crossfade in/out?

[raintheory]

its hard to see a zero crossover in audacity, but i beleive that after you select an area if you press "Z" on the keyboard it snaps to zero crossing.

basically when you zoom way in on a waveform a zero crossing is where the waveform crosses the zero.

[ratbagradio]

I've tried to copy and paste from the left channel to the right to patch it up but it's really difficult to line it up to make it sound exactly right. Are there any shortcuts or easy ways to do this, or is it just a matter of patience and trial and error?

Maybe I missed what you were after -- but why don't you go Split Track -- ie make two separate mono tracks from the one stereo track....

Delete the contents inside the new formed second track (SELECT ALL.DELETE) then copy the original and now top track into the emptied second track. ( Begin at START then PASTE)

Then go back to the original and click MAKE STEREO TRACK.It should, synch as the tracks are bought back together. If not --split again and drag the second new track into place by the move tool.