[LAU] Level Matching

[Giso Grimm]

You might want a loudness model, which predicts the psychoacoustically
experienced loudness of a sound. This is more or less related to the
excitation on the auditory nerve, and should work to bring even
different styles of music to similar "loudness".

I don't know if something like this exists for linux (a long time ago I
implemented a loudness model written in C for my master thesis, probably
based on the one propagated by Brian Moore: B. C. J. Moore and B. R.
Glasberg: A revision of Zwicker's loudness model. Acustica 1996, pages
335-345). If there is interest in the community, I might look at the old
sources and pack them into some kind of "loudness-library" (might be a
useful feature in compressors anyway). Basic concept of loudness
perception is spectral loudness summation, i.e., broadband sounds (e.g.
distorted music) are perceived louder than narrowband sounds of same
level (e.g. classical music). Long term loudness is dominated by the
loudest few percent of a sound (but not by the global peak).

Giso

James Stone wrote:
> On Tue, Nov 04, 2008 at 04:46:05PM +0000, Folderol wrote:
>> On Tue, 4 Nov 2008 17:32:36 +0100
>> "Emanuel Rumpf" <xbran at web.de> wrote:
>>
>>> 2008/11/4 Patrick Shirkey <pshirkey at boosthardware.com>:
>>>> So what the original poster wants is to add a compressor to the output
>>>> path for amarok or whatever audio track player is being used...
>>> I don't thinks so.
>> You are right. I don't want the dynamics of the tracks changed. I want
>> the overall 'loudness' of each track to be similar so I don't have to
>> keep twiddling the volume control.
>>
> 
> 
> If there is a big variation in the level that traks were recorded
> at, I would have thought it would be possible to scan the next
> track in the playlist to find the peak level, and the average
> level, and then adjust the volume accordingly.
> 
> I think the trouble is more likely to be, as other posters have
> pointed out, that some tracks are very compressed and so sound
> "louder" than less compressed tracks, although the peak levels
> are the same.
>