Copy & Paste Makes a "Pop"? Help, Please!

[BGPhilbin]

So, I'm pretty much a beginner with this program - I've used it to good effect for several vocal recordings.

Unfortunately, when I'm attempting to create a good loop track for vocal bass or percussion, pasting the copied portion to the end of the original creates a "pop" that I can't get rid of because it's in the midst of other sound.

I've previously resolved the issue in multiple track recordings by not pasting tracks together - however, I find it necessary for some recordings.

Is there some way to avoid getting this "pop" when editing/copying/pasting?

My thanks,

BGPhilbin

[steve]

If you make sure that the start and end points of your edits are as close to the central horizontal line as possible, (0.0 on the vertical scale), then you should not get noticeable clicks. Sometimes the only way to achieve this is to apply a short fade to the ends of the audio clip.

[BGPhilbin]

You'd think - however, there's no indication of this "pop" in the visual for the audio. You can't see it at all.

And no manner of editing I've done seems to be able to rid me of this annoying artifact in the program.

Seems there might be something I need to do to prepare the copied or cut section for pasting or to prepare the original section for reciept of the cut/pasted object, but I can't seem to find any information on it.

It doesn't seem that the program should actually have such an artifact - I mean, I get that it's free and all, but shouldn't an audio editing program be able to cut and paste without a resulting "pop" or other artifact?

And doesn't everyone have this problem?

Pax, harmonia,

BGPhilbin

[steve]

It doesn't seem that the program should actually have such an artifact - I mean, I get that it's free and all, but shouldn't an audio editing program be able to cut and paste without a resulting "pop" or other artifact?

And doesn't everyone have this problem

Audacity can perform cut and paste without creating pops.
It is not an uncommon problem, but in 99.99% of the time it is due to one of two things:

1) Audio with DC off-set pasted into a track that has Audio without DC-off-set.

Click to expand image

tracks000.png (12.19 KiB) Viewed 2203 times

In this image you can see that the highlighted clip on the right is shifted vertically up above the 0.0 centre line (DC off-set).
During playback, there will be a small click at the edit boundary due to the signal suddenly jumping up to the second clip.

DC off-set is frequently due to recording with a faulty sound card, though some (faulty) format conversion programs can also cause it. The "Normalize" effect can be used to remove DC off-set, as will a high pass filter.

2) edit point chosen incorrectly.

In the example below, the edit in the upper track will click, while the edit in the lower tracks will not:

trackpanel000.png (2.66 KiB) Viewed 2204 times

While making the edit occur at 0.0 on the vertical scale will prevent clicks at the edit boundary, it will not necessarily make the edit "seamless". If one sound suddenly changes to a different sound, (for example a piano note suddenly becomes an electric guitar note), the sharp transition will still be apparent.

In this type of situation you should use a cross-fade like this:

trackpanel001.png (3.47 KiB) Viewed 2203 times

[BGPhilbin]

Interesting. Don't know that I've zoomed in far enough to tell whether this is the case. Looks like there may be something I can use here - I'll look to see if I've got offset parts that I can work together.

Thanks!

BGPhilbin

[kozikowski]

I didn't see any words like: "I removed the DC from all my clips before editing."

It doesn't take very much DC level on your clips to create discontinuities in each cut. You can't hear DC (battery voltage) but you can totally hear when you change it which is what happens at each cut.

You can't remove DC in post -- after editing.

Koz

[steve]

You can't remove DC in post -- after editing

That's true, but there is a little workaround trick.
Apply a high-pass filter (at 20Hz will do the job without messing up the sound), and then repair the transitions where the edit points were (with the "Repair" effect).

[waxcylinder]

..... and then repair the transitions where the edit points were (with the "Repair" effect).

Note to original poster: the Repair effect is only available in the Beta versions 1.3.x and not the "stable 1.2.x versions. However note that 1.2.6 is now fairly ancient and 1.3.7 is pretty mature and stable.

WC

[kozikowski]

<<<and then repair the transitions where the edit points were (with the "Repair" effect).>>>

That's the step you hire somebody else to do. I was going to say the 20 Hz High Pass Filter will totally get rid of any DC Level all in one step, but not each pop, click, or thump. any reason you elected to not use the original Effect > Remove DC Bias tool?

Koz

[steve]

That's the step you hire somebody else to do. I was going to say the 20 Hz High Pass Filter will totally get rid of any DC Level all in one step, but not each pop, click, or thump. any reason you elected to not use the original Effect > Remove DC Bias tool?

It's definitely better to remove any DC off-set before you start any editing...

but let's say you have an audio track that is made of two audio clips (one edit point) and that the two original clips had different DC off-set (or one clip had DC off-set error, and the other did not).
In this case, the DC bias correction in the "Normalize" effect (is that the one you mean koz?) will not work unless you split the track at the "join" and apply it separately to each part (splitting the track into the two original audio clips).

The other limitation of the DC off-set correction that is available in the "Normalize" effect is that it assumes that the correct "zero" position is the average of all sample values which is not necessarily the case for all audio (although it is usually about right for the vast majority of audio).

Using a high-pass filter will effectively remove DC offset throughout the track, even if the DC off-set is not constant (such as in our hypothetical example of two audio clips - however, in this example, the high-pass filter will leave a click at the join, as the sudden jump from one DC off-set value to another is, in effect, a high frequency pulse. This click can be easily smoothed using the repair tool.