Using version 2.0.5 with Windows 7 Enterprise Service Pack 1, installed with the .exe installer.
I stripped the mono soundtrack off a Camtasia mp4 presentation and saved the soundtrack as a mp3 file. I opened the mp3 file in Audacity and it opened as two track stereo, so I did a stereo to mono conversion. I did all my editing and saved as a new mp3 file. There seems to be a loud fuzziness at the upper range of all the words in this 1.25 hour audio.
Is there a way to correct or remove it?
I am not having luck getting the 370k audio to post, so I will post a sample screenshot and try the audio clip later.
The waveform doesn’t look clipped (I don’t see “overload distortion”).
Was the fuzziness present in the original recording? If not, at what point did it appear? If it’s in the original recording, you may not be able to remove it.
I stripped the mono soundtrack off a Camtasia mp4 presentation and saved the soundtrack as a mp3 file. I opened the mp3 file in Audacity and it opened as two track stereo, so I did a stereo to mono conversion. I did all my editing and saved as a new mp3 file.
I don’t know if this is related to your problem, but… MP3 (and MP4) is lossy compression. Audacity has to decompress the file before editing (like all regular audio editors). So every time you re-save as MP3, you are going through another lossy compression process.
If you need to save intermediate copies and you want MP3 as your final format, save as WAV and compress once to MP3 as the final step. And of course, you’ll get better MP3 compression quality if you use a high-quality (high-bitrate) setting.
P.S.
…it opened as two track stereo, so I did a stereo to mono conversion.
Just FYI - With MP4/AAC, or MP3 in “Joint Stereo” mode, there’s no harm in a “stereo” track with identical information in both channels. The compression algorithms are “smart enough” that they won’t compress the same information twice. A WAV file like that will be twice as big as a mono file, but with compression there is no file size or quality penalty.
If you are going to edit the file anyway you might as well save it correctly as mono, but it’s not necessary.
Thank you for the reply. I thought that perhaps the darker blue was the distortion.
I took your suggestion and re-listened to the original mp4. You were correct the distortion is on the original, as well. I didn’t recall it being on there.
So probably no way to remove it, it is ok if saved as is. I was hoping I could edit somehow to make it sound better.
Also, thank you for the information about the save as wav vs. mp3. I wasn’t aware of those drawbacks and I saved as mp3 often while I was editing so I probably made it worse.
The dark (outer) blue colour shows the outline of the waveform, following the peaks of audio signal. Try zooming in and out to see how it looks at different zoom levels (“Ctrl+Mouse Wheel” is a quick way to zoom, or see here for other ways: http://manual.audacityteam.org/o/man/zooming.html)
The inner, lighter blue indicates the “RMS level”. “RMS” is a way of measuring an “average” over (generally short) periods of time. The RMS level is usually a better guide to the “loudness” of a waveform than the peak level. It actually stands for “Root Mean Square” and is described in detail on Wikipedia: http://en.wikipedia.org/wiki/Root_mean_square
