Some sort of crunch I'd like to get rid of


Hi,

Using Vista and 2.1.2.

There’s a music piece I made somewhere but there’s some sort of crunch on several parts I’d like to get rid of. I don’t really know the definition of the faulty bits that’s why I call it crunch. I only remember there has been used some phaser on it. I have used several effects, filters etc afterwards but nothing could correct it. I hope someone can identify the disturbing part - at 1 sec 20 after the bass, it’s repeated one time - and knows how to make it sound acceptable (if possible…).

Regards,

Greiga

Try turning on “Show Clipping” (in the View menu) and the problem becomes obvious.
(see: https://manual.audacityteam.org/man/view_menu.html#show_clipping_onoff)

If you still have the original Audacity Project file, then you can Normalize (Effect menu) before exporting.
If you only have the Audio file, then the damage is permanent (the peaks are missing).

Hi Steve,

I have clipping always on. There’s a lot of clipping but most clipping parts were gone after I normalised. Only some remain. I have only the audio file but where’s the difference? Can’t I make the same adjustments if I import the audiofile in a project? So if I understand it well the peaks have been cut off because of too high frequency or something.

Gr

By default, Audacity uses “32-bit float” format for audio. One of the benefits of “float format” audio, is that it supports signals greater than 0 dB.
Other audio formats do not support signals greater than 0 dB (and sound cards do not support signals greater than 0 dB).
“0 dB” is exactly equivalent to +/- 1.0 on an Audacity track vertical scale.

So, if you have a signal in an Audacity track that is greater than 0 dB, it will sound distorted when played, because the peaks will be clipped by the sound card. However, this can be corrected by “normalizing”.

Here’s a track with a signal greater than 0 dB in Audacity. Note that I have zoomed out vertically and turned off “show clipping”.


If I export that track as a normal audio file (for example, 16-bit WAV), and then import it again, then the waveform looks like this:


In this case, Normalizing will not help because the peaks are missing. “Normal” audio files cannot handle signals beyond 0 dB, so the peaks have been permanently clipped off.

I have clipping always on. There’s a lot of clipping but most clipping parts were gone after I normalised. Only some remain.

Your Crunched Piece.wav file is “permanently” clipped. Normalizing or attenuating (Amplify with a negative dB value) will hide the clipping from Audacity but it won’t fix the distorted wave shape.

There is a [u]Clip Fix Effect[/u] that you can try. When I’ve tried it in the past, it’s made the waveform “look better” but it didn’t fix the sound.

Here is a situation where Normalizing will help - If you have a good (non-clipped) recording and you boost the bass you might “see red” for potential clipping where the waveform goes over 0dB. The waveform is not distorted yet because of Audacity’s internal floating-point processing. If you play the file at “full digital volume” you’ll clip your digital-to-analog converter, but you can lower the volume so it won’t clip. And if you normalize before exporting, the exported file won’t be clipped.

However, if you clip during recording your analog-to-digital converter has clipped the data before Audacity ever sees it.

So now I think I understand, thx! It must’ve been my pre-audacity period probably recording the audio on an online sound program which my sound card did not support enough because of louder than 0 dB.
The question I was going to ask - is there a plugin that can reconstruct the clipped off peaks - is already answered. The clip fix did not help but I have the 2015 version without amplitude reducer, so maybe there’s a last option

Gr