Grandmother: How to sync modulation rate?

The Moog Forum Moog Semi-Modular Analog Synthesizers
1

On the Grandmother, how do I sync the modulation rate EITHER to:

  1. DAW clock (I’m using Logic X)
  2. Arp/seq rate (I can sync this to Logic, so being able to sync modulation rate to this would also solve my problem)

Thank you!

2

I’ve had a good look, I don’t think you can. “Rate in” matches the LFO frequency to the control volatage frequency, not a clock signal. So it’s most obvious use is syncing the LFO frequency to the keyboard frequency to use as an oscillator.

“Sync” syncs the start of the LFO cycle to the trigger, not the Frequency of the LFO.

3

I just tried several ways to have “Rate In” to Modulation clock with the Arp/Seq, which is being clocked externally. Even tried “Clock Out” on the rear panel patched to the “Rate In”, and got some weird noises (feedback?) when the mod wheel was used. Mainly trying to have the S/H rate = Arp rate. Any other suggestions?

4

I think this might achieve what you are trying to do, but haven’t tested.

-Set the rate of the S/H slower than the ARP rate
-Patch KB Gate out to LFO Sync in

When the gate retriggers the LFO, it should grab a new sample and hold value, but that is where I am not entirely sure. If it does, it will change with each note of the arpeggiator, as long as the LFO rate is slower.

5

While triggering the mod rate from the KB-Gate-out does start a new S/H note, the actual mod rate isn’t affected. That I can tell.

6

It is possible I am going mad, but I was working on a patch two nights ago with the arpeggiator synced to my DAW, and I had a long rising and falling filter sweep on the LFO. I noticed it was holding time over two bars, and thought, “oh thats lucky”, then I listened for a few minutes and it held time perfectly.

Is there a chance the LFO syncs automatically when the arp light goes green? I haven’t had a chance to test it properly, but it wouldn’t surprise me too much.

7

Thats exactly how it works, you can check the details on page 27 of the manual

8

I see this is a relative old topic but I think I have a solution to synct the LFO modulation with the Arp. I hope this helps:

  1. Patch KB OUT (Arp/Seq) to CLOCK IN (rear panel)

  2. Patch CLOCK OUT (rear panel) to SYNC IN (Modulation).

Now you can turn the rate knob (Arp/Seq) and the LFO will follow the same rate.
Turning the Rate knob on the Modulation will change the rate in steps like 4/8/16/32 (I hope I describe it right this way)

Hope this will helps.

9

I did a lot of research on the topic, it’s not that trivial as in other analog synths (I have a Prophet 6 where this functionality is built in)

I summarised my findings in this video

https://www.youtube.com/watch?v=7GM15i7BwbI

Check it out!