[PD] isosonic curves : level the perceptual loudness of different pitches

Alexandre Quessy listes at sourcelibre.com
Fri Feb 9 06:29:02 CET 2007

Hi all,

2007/2/8, Frank Barknecht <fbar at footils.org>:
> Yes, it's new. You could use the [list-len] abstraction from
> [list]-abs instead, but you need to check out an older version,
> because the newest one just wraps [list length].

zexy's [length] also does the job, as far as I know.

As I can see, I am still very bad at using the dB unit for audio
amplitude... Anyone has a rule of thumb for this ? Should I use dB
with a simple ADSR filter, let say ? I know that if you use them, -6
dB is somewhat half as loud and +6 dB is twice as loud. Great. Now, in
pd, 100 is unity while in the industry, the consoles use 0 for unity
level. 0 in pd is minus infinity, as far as I know. Now, what is
usable ? After a drop of a few dB, we don't hear anything.
Perceptualy, I find the standard [*~] range of numbers more linear
than using the dB scale.

So, the RMS kind of mean the actual amplitude of the vibrating
membrane of the speaker... http://en.wikipedia.org/wiki/Audio_power :
hence we use [- 100] [dbtorms] for the conversion. Anything else one
should know ?

Perhaps I should put it somewhere on puredata.org after. :)
Alexandre Quessy

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