Fwd: Perceived loudness utility


Subject: Fwd: Perceived loudness utility
From: Kevin Austin (kevin.austin@videotron.ca)
Date: Thu Jul 29 2004 - 06:50:04 EDT


>Date: Thu, 29 Jul 2004 00:00:07 -0400
>From: Automatic digest processor <LISTSERV@LISTS.MCGILL.CA>
>
> 1. increasing / normalizing loudness for large numbers of wav files
>
>------------------------------------------------------
>
>Date: Wed, 28 Jul 2004 04:22:10 -0700
>From: David Robinson <david@ROBINSON.ORG>
>Subject: Re: increasing / normalizing loudness for large numbers of wav files
>
>On Tue, 27 Jul 2004 01:00:39 -0700, Timothy Justus wrote
>
> >Could anyone recommend a good, free program that I could use
>to >increase and equate the loudness of a large set of wav files
>(each
> >containing a spoken word)? Those that I've been experimenting with
>>either require working with one file at a time (e.g. audacity) or
>>introduce large distortion into my files.
>
>Matching the perceived loudness of sounds isn't a trivial task.
>
>Matching or maximising the peak amplitude value in several audio
>files will not match their loudness. Matching the RMS level will get
>you closer, but can still be way off.
>
>I developed a rough-and-ready algorithm called ReplayGain which is
>designed to match the loudness of music tracks by taking the 95th
>percentile of a sequence of frequency weighted 50ms RMS measurements.
>It usually works quite well, but may not work too well for single
>words! You can try it on wave files using this utility:
>
>http://members.home.nl/w.speek/wavegain.htm
>
>You could use a more advance algorithm for matching loudness - but
>maybe in your application you don't want an exact loudness match?
>Maybe the perceived loudness of some words should be slightly
>different from others, and you want to maintain that?
>
>Hope this helps.
>
>Cheers,
>David



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