Doepfer

So far I've just played with it by ear. 

But I'm curious if anyone has already worked out tables or a formula to center any one of the 
BP filters on a particular Hz. frequency.  

I was kind of annoyed the that doc for the A-127 reprints a table from the Allen Strange book 
but doesn't list any approximate VCF Freq. knob settings nor voltage amounts to set the filter 
to those frequencies.

--- In Doepfer_a100@yahoogroups.com, "nicholas_kent" 
<nicholas_kent@...> wrote:
>
> So far I've just played with it by ear. 
> 
> But I'm curious if anyone has already worked out tables or a 
formula to center any one of the 
> BP filters on a particular Hz. frequency.  
> 
> I was kind of annoyed the that doc for the A-127 reprints a table 
from the Allen Strange book 
> but doesn't list any approximate VCF Freq. knob settings nor 
voltage amounts to set the filter 
> to those frequencies.


hello nicolas,

it's a bit difficult to determine the exact knob settings,
as these can slightly differ from module to module.
the simplest way is to hook up a spectrum analyser
and doing a measurement. those formant frequencies are
approximations anyway, you don't have to hit the exact
frequencies to get good results. the table in the
manual should be understood as a hint for own experiments.
maybe i can do some measurements for you during the next
days, i'll post the approximate knob settings then.

best wishes

ingo

hello nicolas,

during the weekend i tried to reproduce the vowel table
mentioned in the a127 manual, using an a127 pcb version 3.
i have to point out that these settings may vary from
module to module, due to component tolerances or
module revisions. use these values as a guide only
and tweak them to fit on your own a127.


ee
1 =  270 hz = 3,5
2 = 1990 hz = 6,4
3 = 3010 hz = 7


i
1 =  390 hz = 4
2 = 1840 hz = 6,2
3 = 2550 hz = 6,9


e
1 =  530 hz = 4,5
2 = 1720 hz = 6,1
3 = 2480 hz = 6,8


ae
1 =  660 hz = 4,9
2 = 1090 hz = 5,9
3 = 2410 hz = 6,7


ah
1 =  730 hz = 4,9
2 = 1840 hz = 6,2
3 = 2440 hz = 6,8


aw
1 =  570 hz = 4,6
2 = 1020 hz = 5,8
3 = 2410 hz = 6,7


u
1 =  440 hz = 4,1
2 =  870 hz = 5,2
3 = 2240 hz = 6,5


oo
1 =  300 hz = 3,6
2 = 1190 hz = 6
3 = 2240 hz = 6,5


a
1 =  640 hz = 4,8
2 = 1350 hz = 6
3 = 2390 hz = 6,6


er
1 =  490 hz = 4,3
2 =    -
3 = 1690 hz = 6,1


best wishes

ingo





--- In Doepfer_a100@yahoogroups.com, "nicholas_kent" 
<nicholas_kent@...> wrote:
>
> So far I've just played with it by ear. 
> 
> But I'm curious if anyone has already worked out tables or a 
formula to center any one of the 
> BP filters on a particular Hz. frequency.  
> 
> I was kind of annoyed the that doc for the A-127 reprints a table 
from the Allen Strange book 
> but doesn't list any approximate VCF Freq. knob settings nor 
voltage amounts to set the filter 
> to those frequencies.
>