Unintended glide on wavetable osc and miniMg osc?

[Antimon]

I upgraded to the latest 1.2.5 firmware yesterday. I had this problem with the original firmware also - 1.1 something.

I make a new, empty, patch, put a wavetable oscillator in it, and connect the oscillator to the output. When I play this I get a kind of quick glide effect, noticeable if I have polyphony set to "Poly Reset", and then play a low note followed by a high note and then a high note again. The first high note has a kind of skidding sound immediately when I press it, the second high note doesn't have that skidding sound. If I play a low note again, it will too have a skidding sound at the start.

It sounds just like I had turned on portamento and left the Port. time low, but portamento is most definitely off. I've tried turning portamento on and raising the time, which yields a similar result as when it's off, only with longer glide. When I turn portamento off I still have this slight skidding effect.

I get a similar result when using the MiniMg VCO, but here it's only apparent when I play a low note followed by a high note, not the other way around.

I was thinking that this was a simulation of an effect that appears in the original vintage synths, but surely a wavetable synth shouldn't suffer from this kind of problem?

/Stefan

[DrJustice]

I just tried this on firmware 1.2.1, and I think I also get that effect with the wavetable oscillator; as if there was a very tiny amount of portamento in effect. I also tried the miniMg oscillator, but I'm not noticing it there - my ears are beginning to become shot for the day though....

DJ
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[Antimon]

Thanks DJ, glad I'm not hearing things that aren't there.

/Stefan

[DrJustice]

It has to be said that this (whatever it is) is so short and minor that it would probably be extremely hard to hear in anything other than a test of a single 'naked' oscillator.

DJ
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[Antimon]

It has to be said that this (whatever it is) is so short and minor that it would probably be extremely hard to hear in anything other than a test of a single 'naked' oscillator.

DJ
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Possibly... it bugged me right away though. I might want to have some fun with fairly naked wavetables. You hear it even if you put a filter in there.

That said, it's only apparent when you play two notes in succession that are far apart, which I'm not wont to do.

Having read reactions to a very similar bug on the DSI Evolver's analog oscillators, others may not be as forgiving.

/Stefan

[DrJustice]

Ah yes, it's not that it should be ignored. Just don't want to create a panic, since it's not exactly a show stopper

Now that I've heard it, I'd like to know more about what it could be and if it will/can be fixed...

DJ

Edit: typo
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[Cord]

Do you get the portamento effect also when TAE is set to zero? I am not in the studio this weekend, so I cannot check, but worth a try.

[Antimon]

Thanks for the suggestion. I tried turning TAE way down and way up - it didn't make any difference.

/Stefan

[BobTheDog]

Hi Guys,

I cannot hear this at all on mine, is it certain wavetables?

Cheers

Andy

[BobTheDog]

Oh yes I can now, the notes have to be a fair distance apart to get it and the glide time seems to increase with distance.

Never noticed that before!

Andy

[Antimon]

I would like to add that this problem applies to all kinds of oscillators, not just the wavetable. It's confusingly similar to a problem with the DSI Evolver - with attack on full speed you will get a very fast glide-like effect it you play notes that are far apart, even if glide is set to zero.