Presumably you could - Use sox with the pick effect to split the file into two files, one per original channel - Use sox with the stat effect to get a correction to normalise each of the stereo files to 100% - Use sox with -v or vol effect to normalise the two files - Glue them back into a stereo file with soxmix. A problem with automating this process is that the correction will be based on the highest peak in the file, and that the perceived loudness of each channel may or may not be related to this. To get a subjective balance, you may need to do the above to get the absolute correction to avoid clipping, then *reduce* one channel or the other according to the average power in the channel - you can probably derive a fiddle factor from the difference in rms values given by stat. I've not tried any of this other than using -v, so it is just a guess... Pete. DJ Astroboy wrote: This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message. Thales, its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt.