Recommended Amplify Settings for Audio CDs?

[LaneLester]

I'm using Audacity 1.3.9 in Ubuntu Karmic to copy some LPs to CDs. I followed the wiki and now am almost ready to export my first file to WAV for burning. The wiki says:

Step 3 - Maximize the volume of the recording
If you did the original recording properly and avoided clipping, the recording is probably not at the maximum possible volume. In order for the CD you burn to be at maximum volume and thus match other CDs in your collection we need to fix this.
Click on Edit > Select > All
Click on Effect > Amplify
The Amplify effect will automatically fill in the values needed to maximize the volume of the recording
Click the OK button to apply the Amplify Effect

That seems to imply that no choices have to be made after clicking Amplify. But a window comes up with three choices to be made: Amplification, New Peak Amplitude, and whether or not to allow clipping. How does one decide what to use for the three choices?

Lane

[steve]

Use the default settings.

By default;
Amplification: Audacity sets this automatically to the highest setting that will not distort. This is based on the highest peak signal in the track. If there is a loud "click" somewhere on the track, then it can fool Audacity and the level will be set too low (the recording will look small vertically and will sound quiet) so you need to check that there are no loud clicks or bumps before you amplify.

New Peak Amplitude: Default is set to 0dB. Audacity uses this setting to calculate the amplification amount. 0dB is the maximum signal possible on a CD. Some people prefer to set this a fraction lower (-0.1 to -0.3 dB) to allow a little "headroom" for the CD player. Typically commercial CDs have a peak of 0dB, so you can safely leave it at the default setting.

whether or not to allow clipping: Off (not selected). This is important. If this is selected it will allow you to set the amplification too high and your recording will be ruined (distorted).

[LaneLester]

Thanks for the help, Steve! There are, of course, clicks and pops, so the question is whether any are bad enough to be a problem. Should the amplification amount be observable in the graph?

Lane

[steve]

The image below shows 2 stereo tracks.
The upper track shows a reasonable volume level, the lower track is too quiet.
If your recording after Amplify looks like the bottom track, Undo (Ctrl+Z) the Amplify effect and look for any sudden spikes (clicks/pops) that may be causing the problem.

tracks000.png (27.49 KiB) Viewed 3001 times

You may find this part of the Audacity wiki useful: http://wiki.audacityteam.org/index.php? ... uter_or_CD
There is also a section about "Click Removal" here: http://wiki.audacityteam.org/index.php? ... ck_Removal

[LaneLester]

OK, mine looks like the good one, so I'm set there.

Thanks for the links.

Lane