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SEQUENTIAL/DSI => Pro 3 => Topic started by: jmg8 on October 11, 2021, 02:38:32 AM

Title: OSC3 irony
Post by: jmg8 on October 11, 2021, 02:38:32 AM
On my Pro-3 the digital OSC seems to be unstable compared to the 2 analog OSCs. It is normally the other way round! 😊
It doesn't have an issue with pitch, it is more something to do with wave reset. On the 2 analog OSC, the wave reset works perfectly. If I make a kick sound, for example, the attack is exactly the same for each hit. But with the digital OSC, the attack changes for each hit. I have slop turned off and wave reset turned on for all OSCs.
Does anyone else get the same?
Do you think a digital OSC should be more stable than an analog one?
Do you have to let digital OSCs warm up like analog ones?
Has anyone found a way to improve this?

Thanks
Title: Re: OSC3 irony
Post by: JayT on October 11, 2021, 04:10:19 AM
Iíve tried wave reset (on every Oscillator) and wasnít happy how it behaves when playing Legato. With retrigger activated it should work, but then you canít play Legato. This may be a thing for Arpeggio soundsÖ.
Title: Re: OSC3 irony
Post by: chysn on October 11, 2021, 10:56:28 AM
I'm not experiencing this. Wave reset on Osc3 seems to work just fine, and behaves a lot like Osc1 and Osc2.

On the other hand, I don't know much about what's going on in your actual patch. What wavetable are you using? What's your envelope look like? Are there any effects turned on?
Title: Re: OSC3 irony
Post by: jmg8 on October 12, 2021, 01:43:22 AM
OK try this...
OSC3 (only) set to a sine wave, drop down 2 octaves and turn off slop and turn on wave reset.
Now repeatedly hit a key and listen carefully to the attack of the sound.
For me, it cycles through being softer and more clicky. This sounds like the sound is starting at zero crossing sometimes but also slipping a little and sometimes not, hence the small click sound.
I think the digital OSC does not wave reset perfectly.
Title: Re: OSC3 irony
Post by: unease on October 12, 2021, 03:39:14 AM
OK try this...
OSC3 (only) set to a sine wave, drop down 2 octaves and turn off slop and turn on wave reset.
Now repeatedly hit a key and listen carefully to the attack of the sound.
For me, it cycles through being softer and more clicky. This sounds like the sound is starting at zero crossing sometimes but also slipping a little and sometimes not, hence the small click sound.
I think the digital OSC does not wave reset perfectly.

When I do this I get almost the same click sound everytime. There is some variation but I guess that could be due to some slight different timing between the VCA envelope and the reset of the wave.
Title: Re: OSC3 irony
Post by: jmg8 on October 12, 2021, 06:48:50 AM
Same as me then, I get almost the same too. The slight variation is the thing I am talking about. On a digital OSC it should be able to reset perfectly. Now try the same experiment with one of the analog OSCs. For me it resets perfectly, I get no variation. This also suggests it can not be the VCA at fault, as all the OSCs share the same VCA.
Please let me know how it goes, is there more variance in the analog vs digital OSCs?
Title: Re: OSC3 irony
Post by: chysn on October 12, 2021, 08:08:55 AM
I think I hear what you're hearing. I have sine wave wavetable at shape mod 0, wave reset on, -2 octaves. For the Osc2 test, OTA filter is around 300, resonance 0, Osc2 wave reset on, triangle shape, -2 octaves. Envelope has the fastest-possible attack.

With both oscillators, the click is occasionally just a tiny bit softer. It's hard to perceive, but I'm pretty sure it's real.

In my case, I don't notice any difference between the Osc2 behavior and the Osc3 behavior. They both have extremely small variations from time to time.  (I just tried the same thing with Osc1 and heard the same slight variations.)

If you set Osc3 to LFO mode and assign it to something (cutoff, pitch, etc.) with wave reset, you can tell that wave reset is working. I'd guess that the variations come from outside the oscillators, perhaps the EG or the VCA, as has been mentioned above.

But it's such a tiny difference that I wouldn't worry about it, personally. I probably wouldn't even hear it if I wasn't listening for it. And I'm not 100% certain that I don't hear it because I'm listening for it.
Title: Re: OSC3 irony
Post by: jmg8 on October 12, 2021, 09:33:47 AM
Hehe. Thank you for testing this.
For me, I hear a difference between OSC1/2 and OSC3.

Huh!? now I am even more confused! I just tested it again and now all 3 OSCs are doing it. The click variation is more audible when pressing the lowest key on the keyboard. I will let it warm up for a bit, recalibrate and try again.

Mostly this is too subtle to matter, but recently I was designing some kick sounds and it makes a significant difference to the transient.
Title: Re: OSC3 irony
Post by: Pym on October 12, 2021, 11:43:20 AM
Yep, transient response in the analog domain is fickle. I'd encourage doing a few samples and picking the best one if you're doing sample based production, as the analog response changes depending on the impulse and there are very subtle changes depending on what is left on the signal path, etc. You can also use very small amounts of attack to dampen this, which leaves you with a more consistent transient.

Essentially our envelopes are 'too' fast. Just play around with it, you don't need a 0 attack to make a tight transient

Hehe. Thank you for testing this.
For me, I hear a difference between OSC1/2 and OSC3.

Huh!? now I am even more confused! I just tested it again and now all 3 OSCs are doing it. The click variation is more audible when pressing the lowest key on the keyboard. I will let it warm up for a bit, recalibrate and try again.

Mostly this is too subtle to matter, but recently I was designing some kick sounds and it makes a significant difference to the transient.