[sdiy] Anyone built the ELEKTOR VOCODER?

[Martin Czech]

:::100 Hz to 2kHz is roughly the tone range of the "singing" voice.
:::The range of the harmonics that are important to recognize (understand)
:::speech is much larger.
:::Although from 8kHz up or so a shelving filter may do.
:::With out the harmonics between roughly 2kHz up it becomes hard to understand
:::speech.
:::While with out the harmonics below 2kHz the voice sounds funny, but is
:::perfectly understandable.


If you are taking the pain to solder so and so many channels, it may
be worth to have a finer and evenly distributed channel pattern then
necessary for vocoder operation. This gives additional applications like
voltage controlled multiband effect filter.

I would think that the additional applications can justify 1.5 to 2 times
more channels, especially as this means only more PCBs of the same kind.
If the filters are pretty narrow, staggered tuning may not be necessary.

40Hz-17kHz operation may be necessary. I can not really hear something
above 17kHz, and below 40Hz envelope detection gets pretty slow, it's
all rumble down there anyway. What kind of PA will process this low
stuff in a clean manner??

Kind of EN inspired fixed filter bank. Don't forget voltage controlled
total feedback arround the whole bank!


m.c.