Oscillator phase of the Nord Modular?

[Quiry]

Hi,

Are the Nord Modular oscillators free running, fixed phase or random phase? I am trying to determine whether certain sounds were created using the Modular and this may provide an easy way of identification as the sound is the same on every sample. Thank you!

EDIT: The question concerns the original Modular and Modular Keyboard.

[Quiry]

A simple recording of few pure sawtooth waves recorded close together is sufficient to determine the phase. If anyone would like to share such recording I will analyse it. Thank you!

[Mr_-G-]

How do you tell apart a free running from a random phase oscillator?

[Quiry]

How do you tell apart a free running from a random phase oscillator?

On fast repeated notes free running oscillators are more consistent since the phase never changes abruptly. The difference becomes immediately obvious when detuning multiple oscillators; the beating remains consistent on a free running oscillator, but random phase breaks the beating pattern on each note.

EDIT: The method a polyphonic synthesizer cycles between voices should also be considered. If the voices are cycled incrementally the phase will likely change on each note until all voices are expended and the above no longer applies. Most synthesizers I have used always pick the first available oscillator so that the same oscillator is chosen for each note of a pattern of repeated notes, in which case this is not relevant.

[maxpiano]

You can download the Nord Modular Editor from https://www.nordkeyboards.com/legacy-pr ... downloads/ and test this yourself (the Editor is lao able to 'lay the patches via a computer sound card, but to run it you need a legacy version of Windows or Mac OS, for example a computer or VM running Win XP) or read the Oscillators section of NSM Manual available on that same page to see if what is specified there.

[Mr_-G-]

On fast repeated notes free running oscillators are more consistent since the phase never changes abruptly.

Do you mean that the repeated notes are played within the same oscillator cycle? or that the oscillator remains in phase across repeated notes?
I suppose that it could only be reliably tested at very low (sub-sonic?) frequencies.

The beating test seems more feasible, though.

[Quiry]

On fast repeated notes free running oscillators are more consistent since the phase never changes abruptly.

Do you mean that the repeated notes are played within the same oscillator cycle? or that the oscillator remains in phase across repeated notes?
I suppose that it could only be reliably tested at very low (sub-sonic?) frequencies.

The beating test seems more feasible, though.

It is easy to test by recording two or preferably few repeated notes of the same pitch. Then, copy the first note on a second track and drag it rightward so that it overlaps both the first and second note. Finally, align the copied note more precisely so that its phase matches with the first note. If the phase then also matches with the second note the oscillator is probably free running, but you should have a third and fourth notes recorded to be certain, since random phase can randomly appear to be free running.

The above does not necessarily apply with polyphonic synthesizers that cycle through the voices, in which case the testing is a little more difficult. You could first record a long reference note on a second track and then see if the phase of repeated notes matches consistently between every nth note. I doubt this is true of the Nord Modular.

If the waveform starts at the same position each time, then it is fixed phase.

By repeated notes I mean that you play for example C4, release, hit C4 again, release. Higher pitches like the C4 work fine. So then for free running oscillator the cycle just goes on and on, only the amplitude is set to zero during silence, but the oscillator keeps running.

[Mr_-G-]

Thanks for the explanation!