Often when I open a file (mp3, flac, wav, etc.) it’s already clipping as it imports it. If I reduce the amplitude after it’s opened, the clipped protion remain clipped but below the 1.0 mark. I can’t recover the portion that has already been clipped which in many cases leaves the music flat sounding.
How do I control the amplitude of the file to be opened so it won’t clip as it’s being opened?
Win 7 Pro
Note that if you have “View > Show Clipping” enabled, the red vertical lines are “warnings” to indicate that audio “may” be clipped. The red lines appear where the amplitude is 0 dB or greater. It is possible to have a perfect unclipped waveform, but if the highest peaks touch 0 dB then red “clip indicator” lines will appear at those points. The reason for this is that many audio formats have an absolute maximum amplitude of 0 dB, so if clip indicators only appeared above 0 dB, then those formats would never show clipping no matter how badly clipped they are.
If the original audio file is clipped, then it does not matter what amplitude it is opened at, it will still be clipped. “Clipping” is when the peaks have been truncated (“clipped”), so the peaks that should be present are missing. In the case of very slight clipping, it may be possible to restore the peaks using “Clip Fix” (http://manual.audacityteam.org/o/man/clip_fix.html) but don’t expect miracles - The effect can only guess at what the missing peaks should be, but if the audio is badly clipped then there is no way that any effect can accurately predict what the missing peaks should be like.
If these are commercial recordings, they are probably victims of the [u]Loudness War[/u]. If they are “homemade” recordings, the ADC may have clipped during recording or the levels may have been over-boosted during post production
When I tried Clip Fix a couple of times, the waveform LOOKED better but it didn’t fix the sound. (But, I’ve only tried it a couple of times.)
“Regular” 16 & 24-bit WAV files, CDs, and FLAC, are integer formats and are all limited to 0dB. (32-bit floating-point WAV files have virtually no upper or lower limit.) Audacity (like most audio editors) uses floating-point internally, so Audacity itself won’t clip. (Of course, you can boost the volume and then get a clipped file when you export.)
MP3 can also go over 0dB without clipping. And since MP3 is lossy and it changes the wave shape, it’s normal to get peaks over 0dB if make an MP3 from a 0dB normalized WAV file. If you then open the MP3 in Audacity, you’ll see potential clipping. I’d guess that at least half the MP3s I’ve made from CDs show (potential) clipping when opened in Audacity. However, in this case the waveform isn’t clipped (unless the original file was clipped) and if you reduce the level in Audacity you won’t see clipped flat-top waves.
it does not matter what amplitude it is opened at, it will still be clipped.
And Audacity doesn’t apply filters or effects until after the music opens. So the original works are distorted.