In earlier versions of Audacity, the playback meter would always show any existing clipping during playback. But now, the playback volume reduces the displayed levels in the playback meter, such that if I have the volume at anything other than maximum, it generally won’t show or detect any clipping.
Is there a setting to get the playback meter to show the clipping, no matter what the playback volume is set to?
How can I tell now if my multi-track projects contain any clipping, before I export?
Yeah, it shows the actual playback volume and it only goes to 0dB so you can’t really tell if it’s clipped. If you generate a tone at nearly 0dB and play it at full volume the meter is going to max-out “in the red” but it’s not clipped.
It’s tricky to determine clipping. View → Show Clipping in Waveform will show red for potential clipping, and similarly, Analyze → Find Clipping will find potential clipping.
Both are simply checking the levels. They are NOT looking at the waveform shape. You can get false positives or false negatives.
Audacity uses floating-point internally, which essentially has no limits so if you amplify or boost the bass, etc., it can go over 0dB without clipping. But it will “show red” for any peaks that go over 0dB (false positive).
Some formats (including MP3)(1) can go over 0dB without clipping but your DAC is limited to 0dB and you’ll clip your DAC if you play it at “full digital volume”.
Or, if you have clipping and you lower the volume with Amplify so the peaks don’t hit or go over 0dB, it will no longer “show red” although, of course, the wave shape isn’t changed (false negative).
The only way you can be sure is to find the peaks and zoom-in horizontally to see waveform and then zoom-out vertically so you can clearly see the waveform shape/peaks. Even then it can be fuzzy because analog clipping isn’t always as cleanly squared-off as digital clipping.
There is a way to check the peaks - Run the Amplify effect and it will default to whatever up or down change needed for 0dB peaks. For example, if it defaults to +3dB your peaks are currently -3dB. Then you can cancel the effect if you just want to check. (The optional ACX Check plug-in will also give you the peak level.)
If I’m recording, I’ll usually check the peaks immediately after recording before any effects. If the peaks are 0dB I assume it’s clipped, and I’ll re-record if possible.
(1) As you may know, MP3 is loss compression. The wave shape changes and some peaks get higher and some lower. If you rip a CD to MP3 it’s not unusual for the peaks to be around +1dB, even though the original CD can’t go over 0dB.
Hey, thanks for the detailed reply, it is tricky to determine clipping in a multi-track project.
That Amplify trick only really works if you have a single track project, since it won’t know if there’s anything over-scale for the exported output of a multi-track project. Similarly, from what I understand, all other “clipping detection” features and plugins have the same issue, where they only detect clipping for single tracks.
The playback meter was the only easy and reliable way for me to know, before exporting, whether or not I had any potential clipping in a multi-track project.
Btw, I’m okay with 0db showing up as red on the playback meter, since I always have my track levels below 0db, which then always meant that “red equals clipping“ so it was a good way to see any clipping.
I’ve found a few workarounds for this, though none are as quick and easy for clipping detection as how the playback meters used to work.
You can turn the playback volume up to max, which makes the meter behave as before, but then you have to turn down your system volume so you don’t blast your ears. And then you have to remember to turn the system volume back up later, which I often forget to do.
You can select all your active tracks and merge them to a new track, and this will show any project-level clipping, like the meter used to. But this is tedious when it often takes a few adjustments to correct the cause of the clipping.
Similarly, you can export your project to a 32bit float wav format, and re-import it to view the clipping, but that’s way too much work, compared to the merge method.
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