Re: Zipper Noise, an example

[Per Boysen <perboysen@gmail.com>]

> Per Boysen schrieb:
>> You hear the zipper noise (of the TC Electronix FireworX) when I  
>> use the MIDI expression pedal to adjust the volume, something you  
>> do a lot when playing guitar (but never with wind instruments).  
>> It's a little annoying but not that bad that I wouldn't use the  
>> volume pedal at concert. Strange thing is that when I use a MIDI  
>> expression pedal to adjust the beat sync tempo division for the  
>> LFO bound filter (on the reverb return) there is no such noise.

On 5 mar 2007, at 23.41, Stefan Tiedje wrote:

> Its very likely not an interference, its just unsmoothed direct  
> control of the amplitude. 128 steps are not fine enough...
> You can test this, as its more audible on low frequency sine waves.  
> if you feed a sound without much overtones/treble and control the  
> volume is it more audible? Its hard to believe, that they don't  
> smooth it.
> In my Max patches I usually smooth it with 20 ms which creates an  
> acceptable latency for volume control...

Hi Stefan,

Smothing was the first fix I tried with the FireworX, but it did not  
change the noise. I have noticed the same zipper noise also when (1)  
controlling other FireworX parameters than volume by MICI CC's and  
(2) in other software when controlling anything by external MIDI CC#  
(Ableton Live, NI Guitar Rig 2).

Anyway, I did a check on what you said about overtone/treble rich  
sounds. But there is no difference to the noise added by moving the  
pedal when I feed the box low notes with no treble and when I feed it  
high and sparkly stuff.

Applications I have been using a lot and where I have never noticed  
any such zipper noise when controlling a continuous parameter with a  
MIDI CC# are Logic and Numerology. Logic has a fader resolution far  
higher than the 128 steps of MIDI and Numerology has a built-in  
"scaling" (i.e. what you call "smoothing").

Greetings from Sweden

Per Boysen
www.boysen.se (Swedish)
www.looproom.com (international)
http://tinyurl.com/2kek7h (latest music release)