[music-dsp] a multiband compression experiment

[Theo Verelst]

At request: the original mix, with no overall multiband compression (but 
the three recorded tracks have individual Lexicon compression+rev and 
built in Kurzweil effects):

    http://www.theover.org/Kurz/ehwyg_nmc.mp3   3.9MB, 256kbps stereo mp3

same recording and mp3 conversion path and settings as the previous 
example. Mixing was done with Rosegarden 176400 kS/s (though some 
programs seem to insist jack at my I7 fedora 14/64 Linux runs at 192k 
instead) built in 32 bit float/ch stereo mixing of three unedited 
one-take live played tracks. I think the multiband version is a little 
softer, both are not normalized to 0dBd.

The highest frequency bands seem not too full, probably because the 
soudnds I ade have filterig built in. Of course recording a 44.1 sampled 
signal at 4 times the speed while I could also simply record the digital 
version isn't necessarily a great idea, but the 15 band filters with 
their own compressors (of which I may not have hand tuned the settings 
very optimally inthis case) sound interestingly neutral this way. 
Conversion to mp3 was done with ffmpeg which warns for internal 16 bits 
conversion.

Oh, I had put on the example without using more than my main (pretty 
big) monitoring system, so I'm glad somebody confirmed again that that 
leads to transparent mixes. I often use a very well amped AKG 271 
headphone (s?) to check as well, which miraculously mostly sounds quite 
similar except form some room effects (as it should) and and also my 
medium sized protable bi-amped (self made) monitors, various 
computer/notebook speakers and a (good) mobile phone.... Occasionally I 
even try out a car stereo with some things I made, maybe I should do 
that more.

Of course the mulitband is an Effect, not a norm, but for radio and 
often TV and for getting a desired mix effect, it appears to work good. 
There are band-overlap centered accent filters in this version, hence 
the non MC version probably sounds more restfull. But remember i nthis 
case it is only the Kurzweil sounds, a mic recording has other 
variations to deal with.

Theo Verelst