I noticed on my LP SE that Osc 1 and Osc 2 glide at slightly different rates. The effect of this is that during a slow glide the osc.'s go out of tune with each other quite noticably.
You can try this example:
Use preset 00 MOOG STAGE
Zero beat the tuning of Osc 2 to Osc 1
Set Glide Rate to max
Now play a glide from the lowest note on the keyboard to the highest.
Because of the slightly differing glide rates, when the glide begins the osc’s go out of tune with each other. But when the destination pitch is reached, both osc. are perfectly in tune with each other again.
What’s interesting is you can hear the osc’s come back in tune with each other as they near the destinatin pitch. During the glide it seems to be about the last octave or so that the glide rates between osc. 1 and 2 (and therefore, their relative tuning) come back together.
Mine does it too. It’s pretty subtle, but during the glide you can clearly hear beats that change in frequency as the oscillators shift tuning relative to each other. Although it goes by fairly quickly, I think what I’m hearing with mine is that the beats get fairly fast right away (in the first octave of the glide), then in the middle octave the oscillators seem to get closer again (the beats flatten out), and in the last octave the beats come back strong but converge again on the final pitch. This is after about 15 minutes of warm-up (and a cold room), so it might be different with the LP either cooler or warmer.
Good description, narrowcaster. Very interesting that yours diverge, converge, then diverge again before hitting the destination key in tune. I’m just guessing here, but it seems to indicate how much the LP osc.'s rely on the lookup table for keyed notes to be in tune. But when the oscillators are “running free” without the aid of the LUT, they behave (noticeably) independently of each other.
It’s been 20 years since I sold my Minimoog, so I might be remembering wrong, but I’m pretty sure, despite its famously drifty oscillators, that during a glide both osc.'s glided at the exact same rate.
I hooked up an expression pedal to the pitch CV and found out that Osc 1 and 2 do not track together. In other words, the scaling of one osc. or the other is way off.
I sustained a note on the keyboard and moved the pedal so the pitch went up about an octave. Just within this short range the ocs’s were way out of tune–strong beating. At 2 octave apart they were about a quarter tone apart, and at 3 octaves apart about a half-step! Yet when keyed the osc.'s were dead on. This seems to confirm my guess that the LP is very dependent on the LUT for keyed notes–and for this it does indeed work excellently. But glide and external pitch CV are another story.
I ran the Note Calibration and the OSC2 Calibration routines. And tried the pedal CV again. Same results. I would expect some deviation in scaling between the 2 osc.'s over the full voltage range, but not not like this with as little as 1 octave. Something is wrong. Is there a scaling adjustment somewhere?
Hope you all understand the spirit of where I’m coming from. I play the LP just about every day. Usually I just get lost in how good it sounds and how much I enjoy finding new sounds. I’ll post a couple examples of how good it sounds as a lead synth. This scaling bothers me though, and I hope I can get some help.