Forums > MaxMSP

digital artifact


FineCutBodies
May 06 2013 | 11:36 am

Could somebody describe me what’s happening when i play this file? I’m trying to add 2 high frequency Cycle~ signals…
There are 2 HighFreq -6dB signals there (above the average hearing limits)… sometimes one is played alone sometimes the other… all good, can’t hear anything…
But when the 2 signals are added, then there is some digial artifact i can hear on a lower frequency… What is strange as i can’t see that on a spectrum analizer…

Do you hear that artifact too? Any ideas how to get rid of it?

wav file: https://dl.dropboxusercontent.com/u/1276843/HiFreQ.wav

Kevin

[attachment=222859,5546]

Attachments:
  1. hiFreq.jpg

    hiFreq.jpg


Peter Castine
May 06 2013 | 12:33 pm

Probably a difference tone?

Not so much a digital artifact as simple physics. < http://en.wikipedia.org/wiki/Difference_tone>.


mudang
May 06 2013 | 6:31 pm

Might also have something to do with aliasing.
[cycle~] is not alias-free. At least it used to be, back in the days…


mudang
May 06 2013 | 6:42 pm

But wait…if it was aliasing it should show up in the spectrum analyzer, right?


FineCutBodies
May 06 2013 | 7:03 pm

yeah, i was thinking maybe it can be some kind of harmonic distrotion on the D/A converter?

really strange…

btw, do you hear any sounds if you check the file?


mudang
May 06 2013 | 8:11 pm

I’m hearing high pitched (>2khz) chirp like bursts.
Using a really cheap onboard sound card.

If you substract the frequencies of the two cycles~ and compare it to the frequency you hear you can tell if it is the difference tone.

Because of the chirp like sound i suspected aliasing


mudang
May 06 2013 | 8:13 pm

Could also be a combination of d/a artifacts, aliasing, difference tones and the harmonic distortion of your ear ;)

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