Normalize audio

First, make a copy of the file. Then do one of the following:

# normalize test.wav

normalizes at -15 dB

# normalize -n 

shows test results

# normalize -a -15dB test.wav

sets average level to -15 dB. The default is very good, so -a is not often necessary.

# normalize -p

uses peak value for basis of the average.

# normalize -l

uses limiter