Clipping!? How worse is it?

[Novoice]

Hello,

 

I checked some of my CDs with audacity and some has clipping. But I dont know how worse is it,

when it breaks out of the frame of audacity.

 

Especially wehen I make from my WAV-Files MP3s: after that, all tracks have clipping.

The tracks gets louder through the process of conversion.

 

So what do You thnik about clipping? Is it hearable whe it is just a little bit?

 

Thanks You.

[astralprojection]

no, dont worry about it.

it doesnt matter.

 

it matters only when you are

a. bouncing a track to wave - you dont want clipping because you dont want your peaks to reach more than oh, -1db or so.

b. when mastering you want to make sure the limiter works at around -0.2db or so, if you are planning on making cds.

 

any other scenario, dont matter. unless the clipping is audible of course, then you might wanna check for a clean source.

 

and it wont be hearable if its not clipping well over the +1db mark, imo. it might, but thats probably not the case here.

[recursion loop]

When making mp3s from wavs make sure that the wavs are peaking at not louder than -0.3 dB. If they go to 0 dB, lower them to -0.3.

[Djuna]

So what do You thnik about clipping? Is it hearable whe it is just a little bit?

Can't really answer that without an example! You mean with converting wave files ripped from CD's, right? How did you rip them in the first place, with what software? And which CD's? That's maybe interesting to know - in a lot of releases there's not much dynamics left in the music after mastering. So if you'll create mp3's from these tracks some clipping may indeed occur, those are artefacts caused by compression.

[Novoice]

Ripped my CDs with cdex. Audacity shows a red thin line by activating the clipping fuction. Some CDs have clipping, some not. Most not...

[astralprojection]

in this context;

it doesnt matter unless you hear distortion, and even then it would still be subjective.

[Purple Sunray]

From a technical perspective:

 

> I checked some of my CDs with audacity and some has clipping.

 

What kind of clipping?

 

Your CD has the audio data stored as 16bit sample values.

Such a 16bit sample can have a value from -32767 to 32767, where 0 is silence (-80dB) and 32767 is max (0dB).

The wav file itself cannot store any clipping, because 0dB is max value a sample can have.

 

If you say that such a CD has clipping, it can come from two sources:

 

1) The mastering engineering fucked it up. He mastered that CD with limiter gain knob on wrong position and produced a signal that goes above 0dB. Since the wav file cannot store values above 0dB, everything above is clipped and you hear distortion most likley. No way to solve that, blame the mastering guy.

You don't see this kind of clipping on audacity necessarily, because the signal is not above 0dB (but it should be).

 

2) Inter-sample peaks.

To re-construct a continuous (analog) signal from a discrete (digital) signal you need an algorithm that does kind of interpolation (a pretty advanced 'interpolation' though )

Your CD has 44.1k samples per second, but the signal on the audio interface output must be continuous, not an impulse-train of 44.1k values per second.

 

That interpolation can produce Inter-sample peaks. That is a peak that is above 0dB, even if none of the sample values is above 0dB:

 

 

Fixing this is easy - don't play the track with volume knob on 0dB, but slightly lower so that inter-sample peaks don't go above 0dB (this is the "lower by -0.3dB" tip by recursion loop)

[astralprojection]

Excellent post, thank you!