Just a quick comment, without having gone into the code (sorry),
balance can create clicks on sudden large differences between the
comparator and input signal.
You could try adjusting the ihp parameter to balance, to control how
fast it responds, and see if that changes the nature of the artifact.
You could also figure out an approximate scaling factor needed when
turing on the effect, and introduce this before balance, so that
balance does not have to do all of the level adjustment (but just the
fine tuning).
best
Oeyvind

2017-02-04 16:08 GMT-08:00 Zoë Sparks :
> Hi Csounders!
>
> I'm having an issue where the balance opcode in an effect seems
> to be causing a click when the effect is switched on. The effect
> in question is a frequency shifter; it splits the incoming signal
> into an upper and a lower part with filters, then frequency
> shifts the lower part down out of human hearing and shift the
> upper part up out of human hearing. balance is applied at the
> end, before output. Without balance, the signal drops
> significantly in amplitude when the effect is activated, but with
> balance, there's a loud click in the left channel.
>
> It's possible that I've just made a silly mistake that I'm
> missing, or that I don't understand the theory behind this well
> enough to diagnose the problem; in any case, I'm pretty stumped.
> The incoming signal has a barberpole phaser applied to it
> beforehand in the chain, so maybe that's playing some role (I'm
> not sure why it would, though).
>
> The application of balance in the frequency shifter is at lines
> 181 and 182 in the attached csd. The line in the score that
> switches on the shifter is 223.
>
> If anyone would be willing to take a look and give me some
> guidance, I'd be very appreciative!
>
> Best wishes,
> Zoë
>
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-- 

Oeyvind Brandtsegg
Professor of Music Technology
NTNU
7491 Trondheim
Norway
Cell: +47 92 203 205

http://www.partikkelaudio.com/
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Thanks so much for your advice!

> You could try adjusting the ihp parameter to balance, to control how
> fast it responds, and see if that changes the nature of the artifact.
> You could also figure out an approximate scaling factor needed when
> turing on the effect, and introduce this before balance, so that
> balance does not have to do all of the level adjustment (but just the
> fine tuning).

For whatever reason, even after playing with the ihp paramter and/or
scaling the signal before balance, the click remained. I was able to get
it quieter by playing with ihp but it never fully disappeared. I ended
up getting a satisfactory result just by hand with a scaling factor,
though, so I was able to take balance out of the equation and I'm happy
now.

That's very good info to know about balance in general in any case! I'll
keep both of those strategies in mind if I run into clicks from it in
the future.

Best wishes,
Zoë

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