Why does it still make sound?

[blave]

I was messing around this morning on the '08, and discovered something: for some patches, even if I turn both OSC1 and OSC2' waveform knobs to "OFF", the synth still makes sound as if there's a third oscillator. Where is that tone coming from?

Specifically, "4OscStrings" (B1-P33) exhibits this. I can turn every parameter (LFOs, ASDRs, etc.) to zero (in addition  to disabling OSC1/2) and it still makes a sound with a sharp attack and gradual decay.

thanks,

Dave
Los Gatos, CA

[lnetzel]

I can turn every parameter (LFOs, ASDRs, etc.) to zero (in addition  to disabling OSC1/2) and it still makes a sound with a sharp attack and gradual decay.

thanks,

Dave
Los Gatos, CA

If you have the filter in 4-pole mode and the resonans quite high, it can self oscillate and make a sine wave sound (keytracking would be a bit off unless the settings are exactly set up for this. Since its the filter making the sound then the oscs are not needed. Could this be it? Turning off the 4-pole mode would make it shut up. There could be mods set up to use envelope to mess with something in the filter to create the decay as well in this scenario.

[blave]

4-pole is not enabled. I should've mentioned that the sound is the same note as what the two oscillators were playing before I turned them off. And again, I have all parameters for all of the "modules" turned to 0. And therefore, the envelopes/filters/LFOs have no impact on the "phantom" sound.

The way I discovered this is that I turned glide/portamento on for OSC1 and OSC2, and I would hear the glide happening but the the "phantom" note was also playing, with fixed pitch.

[Sacred Synthesis]

I was going to suggest that it's oscillator bleed, as is common with analog instruments.  If I turn the audio sources down on my Prophet 08, I can still hear very very softly the oscillators.  I've never analyzed the sound as you have, because I've come to expect such imperfections in synthesizers.  I believe this question was asked on the other forum, and DSI said it was this oscillator bleed.

One question, though: is the sound you hear related to layer A or Layer B?  If layer B, then this might explain why adjusting parameters has little effect on it.

[blave]

One question, though: is the sound you hear related to layer A or Layer B?  If layer B, then this might explain why adjusting parameters has little effect on it.

Oh yeah, Layer B. <whistles, looks at the sky>. Nothing to see here, other than the moron (i.e., "me")... move along.

When I hit the Layer B Edit button and turn off the oscillators, it sounds -- silent! 

Sorry, I messed around with programming when I first got my '08 a couple months ago, and kinda forgot about Layers. Duh. Thanks for your reply.

Dave.

[Sacred Synthesis]

Excellent.  Your welcome.