How do I minimise pops when punching in and out

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gastric_bass
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Sometimes when I am recording something with punch in and punch out I hear a (sometimes pretty silent) crack or pop when the audio changes between the old recording and the new recording. It mostly happens when I am recording (electric) guitar.

I can try to change the position and sometimes it works - but there are some punch in and punch outs where I don't get any position where it may work.

My guess is that the reason for this might be phase shifting.

What is the best strategy to minimise these problems ? (right now I am adjusting the start / end position until the effect is minimised)

paul
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its almost impossible for there to not be some kind of artifact when you switch from monitoring existing material on disk to new material flowing in through your audio interface. the problem is not anything remotely as complex as phase shifting - its simply that there is a discontinuity in the audio - its like switching between two entirely different recordings. how bad the discontinuity is will depend on the existing material on disk and the new material, and could vary dramatically and, to a human, appear to be mostly random.

i'll leave it to the practitioners to make real-world suggestions about how best to tackle it.

BenLoftis
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Are you saying that you've got a long take "A" and you punch-in an overdub("B") on the same track ?

Trimming the start and end times to find click-free transitions is the correct approach. Ardour will put a short crossfade from A->B->A. Make sure that your "short crossfade" time is set to a reasonable time (15-30ms) in Windows->Preferences->Misc.

Another fix might be to lengthen the crossfade time to minimize the click. Unfortunately this is not adjustable with current A2 or A3, but some new code in the Mixbus branch will allow you to lengthen the crossfade going into and out of an overdub. This code will be released in a future Mixbus update and will likely find its way to A3 also.

Have you checked for DC offset at your soundcard input? If the two recordings have a dc offset wrt each other, then you'll get a click.

gastric_bass
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Yeah - overdub would be the correct word for what I was doing. I've tried to adjust the crossfade, but the best remedy was to try to find click-free transitions.

I just didn't know what to search for. Sometimes the best cross over point was when there was full signal (if there are areas with breaks, this was usually the best point for overdubs)..

Is the DC Offset a problem of the soundcard ?
It was recorded with the same soundcard - the only funny thing is that it happened mostly with electric guitar (micing the guitar cabinet). And they have got some random noise, even when there is no signal.

paul
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@gastric_bass: ah, Ben's question reminds me that there are two possible things you could have been asking about: the audio during the overdubbing process, or the results of the overdub. which one was it?

gastric_bass
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@Paul: I am talking about the result of the overdub. It would be cool if I could use something like the "crossfader edit window" for the crossfade between the original track and the overdubbed part. Is this already implemented - would be a cool feature otherwise..

anahata
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If you split the original track under the overdub you will get normal crossfades that can be edited.

I'd have thought that adjusting the join point by trial and error, combined with Ben's suggestion to edit the "short crossfade" length, should enable you to find an inaudible join. If not, maybe you didn't capture enough material before and after the overdub point. On a guitar, immediately before the start of a note is usually a safe place for the join.