Normalisation

Special Interest Groups Audio Processing
1

Hi all

The normalising options have a ‘normalise to -3db’ check box. If I uncheck this, do I normalise to 0db? Otherwise, is there any other way of normalising to 0db?

Thank you,

CrayC

2

In 1.2.x? You can only get -3dB normalization using Normalize. To boost the peak amplitude to 0dB, you can use Effects > Amplify, and accept the default amplification value.

In 1.3.x you can choose what level to normalize to.

3

Thank you (it’s 1.2 I’m using). So what’s the difference between amplifying a wave and normalising it?

4

Normalise boosts each track in the project independantly, to the same maximum level.

Amplify applies the same gain to all the tracks in the project, and you can choose that gain in the amplify effect dialogue. It so happens that the default gain is set to the maximum unclipped gain, but this is just a convenience.

So the difference is non-existent if you have only one track in your project.

5

OK thank you very much. Then what is the difference between amplifying a wave and just turning up the volume? When I export as a WAV file, will the setting of the volume controls on each track make any difference at all, or is it just the size of the wave that matters?

Cray

6

Hi Richard,

I guess there is no way of determining the overall headroom of a mix?

→ Normalise increases each track to peak say at 0dB, i.e. highest peak in all tracks will be at that level.
→ Amplify suggests an amplification value, so that the track with the highest peak will peak say at 0dB, with other tracks peaking at a lower value. However, this might still mean that the overall mix is distorted in places.

So how can I work out the loudest peak in a mix? And how can I make sure that the loudest peak in a mix is below 0dB? See earlier post here http://audacityteam.org/forum/viewtopic.php?f=20&t=61

7

You can make sure the highest peak in a mix is below 0dB using two methods:

  1. save your project, then select everything and click Project → Quick Mix (in 1.3.3, Tracks → Mix and Render). Hopefully you should be able to see if anything is clipped in the new track. Then just undo and you’ll be back to where you were before mixing down.

  2. play the whole project. As long as the Meter Toolbar is selected and working, it will show a red line at the top of the meter if any sample has clipped.

8

i try to do it but there were an error shown up.