Moog oscillator phase

[Shayne White]

I have an interesting question...I have both MiniMax (Scope) and Arturia's MiniMoog V. I made a sound in MiniMax where the 3rd oscillator, running as an LFO, was controlling the filter. When I set the LFO to the narrow pulse type, it made a percussive-like sound, similar to a sawtooth, because the positive part of the cycle was narrow and the negative was wide -- and it sounded good.

In the Arturia version, the phase of the oscillator was flipped. The wide part was positive, the narrow part was negative -- so it just sounded like harsh mush instead of being percussive.

My question is: what did the original MiniMoog have? Was it positive-wide or negative-wide? Considering that the original illustrations on the panel of the MiniMoog showed a narrow positive and a wide negative pulse width (and that's what Arturia's version shows as well!), I'm inclined to think that CreamWare got it right, and Arturia got it wrong (like many other things they got wrong!).

Does anyone have a MiniMoog they can try, or does anyone simply know the answer?

Thanks,

Shayne

[hifiboom]

they may sound similar when you dial in some standard oscillator sound, but once you use osc3 as lfo and extensive use of filter, the A version has its pants off and sounds like most VSTis,

boring.

without having a demo sound of what you mean, I swear minimax is closer to the original.

no contest

[Shroomz~>]

This quote from an SOS review of the Artu*ia from sometime in 2005 pretty much explains what's going on. The guy is comparing the VSTi to his real mini.

I have long felt that the pulse width on my Minimoog needs a tweak to return it to its original 'hollow' tone. On Minimoog V, pressing the Shift key while dragging the mouse over the Waveform knob allows you to change the duty cycle of any of the pulse waves from 0 to 100 percent. I discovered that the duty cycle of my Minimoog is closer to 47 percent than 50 percent, which accounts for the difference in tone. Similar calibration inaccuracies in the vintage synth also result in timbral differences between the two instruments for the narrower pulses — not that these matter, given the ability to adjust the square wave's duty cycle.

The triangle waves exhibit a far greater difference in tone, with Minimoog V being much the 'woodier' of the two. But now we come to the mixed triangle/ramp wave. This is audibly not the same waveform on Minimoog V as it is on my Minimoog. The difference is so significant that I have produced the two oscilloscope traces overleaf to demonstrate the point.

While I had the oscilloscope running, I decided to check the other waveforms. The Minimoog V's front-panel graphics are correct, with ramp (rising sawtooth) waves depicted for Osc1 and Osc2. Nonetheless, these settings produce falling sawtooth waves (the same wave but with its phase reversed). Likewise, the ramp setting on Osc3 produces a sawtooth, and the sawtooth setting produces a ramp! This means that the software is calculating the waveforms correctly, but that the phase of the output is inverted. It probably makes no difference at audio frequencies, but it's still not clever.

On the other hand, it's only right to compliment Arturia on the addition of the user-definable pulse widths mentioned above, and on the ability to adjust the shape of the triangle wave and the triangle element within the triangle/ramp waveform from saw-like to ramp-like. There's also the welcome addition of chromatic tuning. Hold down the Shift key while adjusting Osc2 or Osc3 tuning, and the pitch changes in precise semitone steps.

[Shayne White]

Thanks, I forgot I could change the pulse width freely! That's a nifty little feature that Art. included.

But it still doesn't sound as good as MiniMax!

And I actually don't like the right/shift-click semitone scheme. I like the original frequency knob scheme better.

Shayne

[astroman]

I'd never play Minimax with more than one Voice

[valis]

The interesting thing about the Arturia inaccuracies in these things is that they're consistant across their VSTi's (until SoS or someone widely read points them out, in which case they're often quickly 'corrected' in an update). This might lead one to believe that the underlying code is largely reused...

[hifiboom]

It would be really interesting to get an idea, why they start with the origin concept. I mean I like the concept itself quite well, and the usage seems easy and fine too, but ....

Combining different oscillators and filters and that stuff, which all more or less sound the same, won`t result in much different sound at all.

If you have one, you got them all and still nothing.