I’ve imported many .m4a files into Audacity and they all playback with clipping. I’m getting these files from iTunes, so I don’t have the option to export a different file type.
Here’s a screenshot of an example waveform that is getting clipped.
And I’ve tried to duplicate their fix (can provide screenshot in comment if that would be helpful), but to no avail. That thread is quite old and it appears my version of Audacity has some different options. However, I don’t really know enough about these things to really know what this fix is supposed to be doing or how I might need to adjust for the new version.
Could I please get some advice on how to either change my file types from iTunes or how to import these .m4a’s properly so that they do not clip?
I was encountering clipping as well when trying to record these tracks through my desktop audio, hence why I went ahead and purchased the iTunes tracks–I thought they would be better quality and work normally. So, perhaps it’s more of a playback issue than an import issue.
It might just be Whoever produced the track did it intentionally to win The Loudness War.
And/or lossy compression (m4A, MP3, etc.) changes the waveshape making some peaks higher and some lower. The new peaks may go over 0dB. Many if not most of my MP3s that I ripped from CDs go over 0dB and “show clipping” in Audacity.
But if you M4A or MP3 goes over 0dB without clipping it will clip your DAC if you play it at “full digital volume” because your DAC can’t go over 0dB.
Regular WAV files are also limited to 0dB so it’s a good idea to run the Amplify or Normalize effect to bring down the level a bit before exporting to WAV. (In general, it’s a good idea to keep your peaks at or below 0dB even if the format supports it.0
These formats can actually go over 0dB without clipping and if that happens audacity will “show red” if you have “show clipping” enabled. Audacity can also go over 0dB without clipping so you can get false positives. (You can also get a false negative by lowering the level.) longer show red.)
FYI - All of the popular streaming services use loudness normalization to make everything about the same volume. As a result, MOST music files are reduced in volume and they will be quieter than the CD or downloaded MP3 or M4A.
The volume reduction doesn’t fix any clipping or remove limiting/compression but makes the loudest tracks “quieter” and the waveforms are “smaller” and it’s less likely that Audacity will “show red”.
Some are quiet-sounding files are boosted, but they don’t boost the volume into clipping even if that means they can’t hit the loudness target.
Well, it’s all music. It’s a variety of genres as I’m trying to make a setlist for an ecstatic dance. Many of the songs feature lots of horns, though.
I also imported a couple of .mp3 tracks to compare, and none of those were clipped.
I know another responder, @DVDdoug, mentioned it being possible to have a false positive with clipping, but it also sounds really terrible when I try to play these tracks through Audacity.
So, I should just apply the “Normalize” effect to all of the tracks? Does this result in some sort of “less pure” version of the track than I could get if I were able to obtain a different (less lossy) file type? I don’t know enough about it to understand if “normalize” actually changes the sounds quality or quality potential in any way.
It “doesn’t hurt” and it MIGHT help. It’s “good practice” to keep the peaks at 0dB or less. (1) Normalization is a simple volume adjustment (similar to adjusting the volume knob on your stereo up or down) and it does NOT hurt the sound quality.
…I suspect it’s just a “bad production” and it’s probably always going to sound bad. But whoever produced it probably thinks it sounds good…
You can export in a lossless format if you wish.
When you open the file in Audacity it gets decompressed (the same as when you play it). If you re-export in a lossy format you are going through another generation of lossy compression. The GOOD NEWS is that with M4A “damage” doesn’t accumulate with successive generations of re-compression. (With MP3 damage DOES accumulate.)
(1) Nothing bad happens when you get close to 0dB unless you are exporting to a lossy format and then some peaks in the exported file might go over 0dB.
Okay, that makes a lot of sense. Thank you for explaining all of that to me!! I’ll get to Normalizing!
My only lingering concern is that nearly every (out of almost 30) mp4 files that I’ve imported have the same clipping (and therefore sounding fuzzy/as if it’s overwhelming the output system) problem. That seems… like there’s an underlying issue still that maybe I could address. But maybe it is all due to the Loudness War (thanks for sharing that link, btw).