Moog Music Forum

I just acquired an analog oscilloscope and I thought it would be interesting to see the waveforms the Moog One is producing. Starting with an Init patch, with Osc 1 set to Triangle Wav and the Mix Knob all the way to the left: Playing a Middle C the waveforms match what's on the LCD as I sweep the Wave Angle Knob. But as I move up the keyboard, the wave diverges. Two octaves up and the LCD looks like a sawtooth with Wave Angle to the left but the Oscilloscope says that it's a pretty regular triangle wave.

Switching the Osc to Sawtooth is even more interesting: rotating the Wave Angle knob gives you a range from saw to triangle to reverse saw on the oscilloscope, but on the LCD it barely changes the shape from saw to saw with slightly longer attack.

So I am wondering the usefulness of the LEDs on the One, if they are so often not showing what's going on. (Yes, I am running straight from the SUB outputs to the oscilloscope, no effects, just one oscillator, no filter....)

I'm also finding that because the Wave Angle knob lets you sweep the full range from saw to triangle to reverse saw, that the Triangle/Saw switch is kind of unnecessary? Maybe I'm missing something....

The manual says

"Together, their combined signals can be used to create an endless array of wave shapes that determine each Oscillator’s final sonic output. The OLED screen in the center of each Moog One Oscillator provides a static image of this composite waveform.

NOTE: The static image displayed on the OLED is created by the Oscillator’s parameter settings only, and does not reflect any real-time modulation routings that may also be affecting the final waveform."

Like I said, I wasn't applying any modulation, and the mix knob was set fully to left so that only the sawtooth/triangle side was active.

The Saw and Tri mode of the Moog One VCOs use a different waveshaping process or core oscillator. So the resulting waveshape is audible different, even if both are set to a saw waveshape. These small variations make a different character of the VCO. Much like having two different VCOs from different synths available. This is unique to the Moog One.

And even listening to the straight Minimoog saw will give you different character, depending on the VCO board revision of the MInimoog. Small changes cause audible differences. And there are not many synths with these slight variations while playing more or less a saw waveshape.

From the manual:

...
Selecting Triangle allows continuous change of the wave’s rise and fall times via the WAVE ANGLE knob -- sweeping from a Sawtooth to a symmetrical Triangle to a Ramp (Reverse Sawtooth) wave. Selecting Saw varies the reset time of the wave.
...

Thank you for the excellent explanation! It does make sense why those options are available. (It doesn't quite explain why the waveform in the LCD sometimes is very different from what shows up in the oscilloscope, however.)

As i understand it the lcd displays the setting of the knobs , it’s not an osciloscoop. your osciloscoop is a accurate waveform display, the lcd just a “slight” indication of how your knobs are set ?
It also looks great i must admit
How the lcd changes way up the keyboard is interesting .