I am trying to write a simple chain to process, perhaps, a few hundred mp3 files at a sitting. The first step is to truncate silence. The second step is to amplify. I would like to amplify to a “New Peak Amplitude” of 0.0 dB. However, when editing the chain the only parameter for “Amplify” is “ratio”, which to me corresponds to the “amplification” parameter. In addition, there does not appear to be way to check the “Allow Clipping” checkbox (which I really don’t need anyway). I know I could probably use “Normalize” but I was wondering if it can be done with “amplify”/ Thanks for any guidance!
There’s some discussion whether you want to do this in Audacity at all. Audacity doesn’t edit MP3. It makes an internal copy of an MP3 show and then makes a whole new one when you’re done. It’s this second MP3 that causes problems. Because you’re making an MP3 from another MP3, the honky, bubbling compression sound damage doubles assuming the same filesize. You can get around this by increasing the MP3 size, but that’s more involved and people tend to fall in love with the original filesizes.
Audacity Amplify defaults to work so that the highest peak is 0dB. You can probably apply the tool and do nothing else. You should know that neither Amplify and Normalize have any idea what music is and do not work on show volume or loudness. If you have a cat hair pop on a record you transferred, that will drive Amplify nuts and destroy the show.
You should also know that automatically sensing silence can cause problems. If you have low level performances with background hiss, the tool is going to make many mistakes. You didn’t say whether or not you had fixed length silences you wanted to delete.
Koz
Both “Amplify” and “Normalize” are amplification effects.
The main difference between them is that “Amplify” amplifies by a specified amount, whereas “Normalize” amplifies to a specified level.
If you want to “amplify to 0 dB” in a chain, then “Normalize” is the effect to use.
These effects are described in more detail in the manual:
http://manual.audacityteam.org/o/man/amplify.html
http://manual.audacityteam.org/o/man/normalize.html
Thanks for the constructive suggestions. The chain I intended to use was actually three steps: 1) truncate silence; 2) amplify or normalize; and, 3) export to mp3. I had read some of the discussions regarding the dangers of truncating silence and the unintended consequences of removing soft passages in the middle of the selection. My intent, as many others had wanted to do, was to trim the silence from the beginning and ending of the track. I was thinking about setting the parameter to: min 500ms duration: 200ms level:-75dB compress: 1:1.
Looks like “normalize” might be the way to go. I appreciate all the help.