Audacity Forum

Yes there is clipping, and the 24/96 export has "wrapped" the over 0dB samples rather than clipping them.
Digital audio is represented by a series of binary numbers - If you count up to the highest possible number for the number of "bits" (24 bits in this case) and then add one more, it flips to become negative, then as you keep counting it becomes less negative. Similarly if you count as far negative as possible and then keep going, the number will flip to positive.

Here's a simple demonstration counting with 3 bits:

000
001
010
011
100
101
110
111
000 [email protected]!

Now look at this close in zoom of your files: (the upper track is the 16 bit file)
As you can see, it is really important to avoid clipping.

By default Audacity works with 32 bit sample values, which can handle values over 0dB, but 16 or 24 bit files cannot represent these values correctly.
You could avoid the polarity reversal by deliberately truncating the samples before you export, but obviously that will give you "clipped" (truncated) flat tops and bottoms to the biggest peaks which, while not too noticeable if there's only one or two, is not desirable. A better (and the "right") way to avoid the problem is to Normalize or Amplify the track/mix before you export. I would recommend Amplifying so that the maximum peak is no more than -0.3 dB.

Cool! thanks for the info and taking time to help me out. One last question. What if my original recording has an occasional clip but it is not audible?

Kelly

cosmickc wrote:What if my original recording has an occasional clip but it is not audible?

If it's a 16 bit recording, then that would be a good candidate for using the "Clip Fix" effect.
If it's a 24 bit recording, then it depends if it's just clipped (top/bottom chopped off) or if it has "polarity reversal" (as shown in previous screenshots).
If it is a 32 bit recording you may be able to fix it simply by "Amplifying" it to a lower level.

In either case, zoom in close on the clipped section, then Right Click on the vertical track scale - the scale will change to show a range of +/- 2.0
You will now be able to see if the peaks have been chopped flat, inverted, or extend beyond +/- 1.0 without being clipped (this last possibility may occur with a 32bit track).

If the waveform extends beyond +/- 1.0 but is not clipped, simply select the entire track and use the Amplify effect to set the maximum level to -0.3dB.

If the waveform is clipped flat at top or bottom, make a note of the effected audio then select the entire track and amplify by -10dB (minus ten).
Now zoom back into the effected area and find the part of the waveform that contains the clipped audio. Select the affected region and apply the "ClipFix" effect. You should see the waveform "restored" to an unclipped condition. (note this is only effective for occasional clipped peaks and should be thought of as an emergency repair rather than a regular working method). Repeat ClipFix for all affected areas. Then select the entire track and apply "Amplify" to bring the peak level up to -0.3 dB.

If you have "polarity reversal", Use the same method as for normal clipped audio, but if it is a stereo track, split it to two mono tracks first, then use this modified ClipFix effect. (the split stereo may be converted back to a stereo track after processing, but this modified ClipFix ("ESP-ClipFix") only works with mono tracks.)

Thanks again for all the help.

KC