Waveform is flat on top and bottom

[pdun459]

Hi folks. I edit a lot of classic rock files with Audacity and I've got one that has me scratching my head. It's Joan Jett and it looks like it has major clipping but I'm not sure. The top and bottom of the waveform is mostly flat but not over 0. That's how the whole CD looked after being ripped and before any editing. It's pretty hard rock so is that just how some rock waveforms look? I've got some Ramones files which are really hard rock but the waveforms aren't flat. Here's a picture.

[kozikowski]

I have some Electro-Dance tunes that look like the waveform display was spray painted solid Krylon blue. What does it sound like?

Koz

[DVDdoug]

Yeah, that looks clipped. It's somewhat strange that it's clipped below 0dB, or rather it's slightly strange for a professionally released CD to be clipped below 0dB.

A lot of modern (or remastered) CDs are hard-limited, compressed, and even clipped due to the Loudness War, so it's not unusual to see a recording that looks like that, but usually they are clipped at 0dB to get the full-loudness effect. If they've done a good job, it may not sound bad (and I've seen worse).


BTW - If you make that CD into a vinyl record or encode it to MP3, you will get phase shifts and/or filtering that makes the waveform look a little better by making some of the peaks higher and some peaks lower with the peaks less squared-off. But of course this doesn't remove the distortion.

[pdun459]

Thanks for your informative replies. I feel a little embarrassed now, I think it was just the Zoom. When I set it to Normal it looks fine. It sounds pretty good too. Here's a picture of the same file on Normal Zoom.

[kozikowski]

No, the original performance probably doesn't line up conveniently like that. That's very heavy processing. Koz

[steve]

If the CD was "ripped" (digitally extracted) then what you see in Audacity should be (virtually) identical to what is on the CD.
If you "recorded" the CD, then that is not the case - the quality of the recording depends on the quality of the CD player, the sound card, and the sound system settings.

You can check if a waveform is clipped by zooming in really close so that the individual waveforms are visible. Here is an example of a track that is clipped. Note how the bottom of the waveform is flat:

firsttrack000.png (11.89 KiB) Viewed 1619 times

Here is a dance track that is heavily compressed to make it as loud as possible. It certainly looks like it is clipped:

firsttrack001.png (15.05 KiB) Viewed 1619 times

But if we zoom in really close, we can see that it isn't actually clipped at all, just very heavily maximised for loudness:

firsttrack002.png (12.3 KiB) Viewed 1619 times

[pdun459]

steve, I zoomed in and it does look like it has a lot of clipping. Thanks for sharing that tip. Fortunately it still sounds pretty good. It could always sound better but considering my equipment it's not bad.