musicdsp.org source code archive - WSInf

...
(missing type and asterisk in the first calc line ;).
I tried morphing from one vowel to another and it works ok except in between 'A' and 'U' as I get a lot of distortion and sometime (depending on the
signal) the filter goes into auto-oscilation.
Sebastien Metrot
from : larsby@elak.org
comment : How did you get the coeffiecients?
Did I miss something?
/Larsby
from : stefan.hallen@dice.se
comment : Yeah, morphing lineary between the coefficients works just fine. The distortion I only get when not lowering the amplitude of the input. So
I lower it :)
Larsby, you can approximate filter curves quite easily, check your dsp literature :)
from : alex@smartelectronix.com
comment : Correct, it is for sampling rate of 44kHz.
It supposed to be female (soprano), approximated with its five formants.
--Alex.
from : ruiner33@hotmail.com
comment : Can you tell us how you calculated the coefficients?
from : antiprosynthesis@hotmail.com
comment : The distorting/sharp A vowel can be toned down easy by just changing the first coeff from 8.11044e-06 to 3.11044e-06. Sounds much
better that way.
from : jnorberg [ AT ] gmail [ DOT] com
comment : Hi, I get the last formant (U) to self-oscillate and distort out of control whatever I feed it with. all the other ones sound fine...
any sugesstions?
Thanks,
Jonas
from : texmex@iki.fi
comment : I was playing around this filter, and after hours of debugging finally noticed that converting those coeffecients to float just won't do it. The
resulting filter is not stable anymore. Doh...
I don't have any idea how to convert them, though.