Softsync

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WHAT IS SOFTSYNC ? HOW DOES IT WORK? Modulation von Oszillatoren. Dabei steuert OSC1 den zweiten, indem der Zweite jedes mal seine Vorzeichenrichtung ändert, wenn der OSC1 die Mittelnullinie erreicht.

I don't know much about how Soft-sync works but it does seem to change tone depending on how the phase of the VCO waveforms are lined up. If I press it on, and off about ten times, you here a different tone at each of the 1 tries. most of them similar, but a few of em will be heavily phase cancelled and tiny. Is this how it works?

BTW

I have a saw on VCO1, and a square wave on VCO2, one octave down

Generally the way synch works when VCO2 is synched to VCO1, is that every time the VCO1 waveform has a positive-going zero crossing (i.e. begins its cycle), the waveform of VCO2 is reset to the beginning of ITS cycle. That's hard synch. With soft synch, the VCO2 waveform does NOT reset for every time VCO1 begins its cycle. It only resets if it is near the end of its cycle, and about to reset anyway.

I'm not sure if that's correct; I believe that any sort of synch relies on the rising edge of the "master" waveform to reset the phase of the "slave". In Soft Synch, the slave oscillator can be caused to completely lock in phase with the master if their tuning relationships are consonant (octaves, fifths, etc.) It is often neccessary to tune the slave oscillator flat several cents in order to achieve a lock. Check "70's Lead" for a soft-sync'd sound and check the tuning of osc 2. Note that the timbre of a soft-synch'd oscillator changes a bit, even if the master and slave are at the same frequency. In hard sync, the slave becomes a generator of harmonics as it attempts to both freerun and also reset to the rising edge of the master's waveform cycle.

Not all voices will accurately soft sync due to the compromise between the sensitivity requirements of the circuit and the differences in tone which occur. It is an effect which is great for organ sounds (pipe and otherwise) and for firmer bass sounds as well. I've found that if the slave is tuned -below- the master, it will lock a bit better (and IIRC, it's tone is a bit cleaner.

If a slave is exactly twice the frequency of the master, it will produce two complete wavecycles in the exact period of the master's one, with the rising and falling edges being the same for both at the ends. This is useful when creating complex single-cycle waveforms for looping in small memory spaces in ROMplers (means: samples are use that are in the ROM/the fixed memory of the synth). Octloc (sp) in the QS synths was from Emerson's Moog Modular, with three 921bs in soft sync, each an octave higher than the other. I had a sound, Morgan, in a factory set a few revs ago, which was osc 2 soft sync'd to 1 but two octaves higher, both oscillator producing square waves and the suboctaves at equal volume, for a 16-voice stack of four perfectly-in-phase square waves. There were sounds like this as leads in the Morg Garson "Moog" records such as Black Mass.


(One of the cooler features of the Wiard VCO is that there's a synch *pot*, which can be adjusted from no synch, through varying degrees of soft synch with the threshold for >oscillator reset being changed, to rock-solid hard synchronization ... I >don't know of any others that allow this.)

I was in touch for a short while with a gent who was creating a feature- packed modular called the EVOS (info in the AH archives). It never saw the light of day AFAIK but it's oscillators had the same continuously variable Sync input function.

You have a Wiard? :-)

So with soft synch, if VCO1 & VCO2 at close frequencies, BUT freerunning,whether or not VCO2 will synch to VCO1 may vary based on slight phase/frequency differences between the two oscillators. And as those differences will change over time, yes, the synched sound may vary depending on exactly when you hit the "synch" button.

If you don't have the slave oscillator detuned into the "groove" which allows soft synch to lock, it can jump in and out of synch creating it's own effect. James Reynolds created a sound, "Faux Organ" in the factory presets which takes advantage of this effect, IIRC.

I know that the curtis (CEM) 3340 oscillator had a soft sync input pin as well as a hard sync input but I don't remember any CEM synths

with this feature.

Synths I know of with Soft Sync:

Moog 921b oscillators Roland SH5 (you have to tune it's slave oscillator flat as well as the A6s) Matrix 6 (Oberheim)