Voyager XL as a MIDI gate interface, for Modular CV sync?

Tips and techniques for Minimoog Analog Synthesizers
Post Reply
User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Wed Apr 14, 2021 8:55 pm

Trying to sync a Dotcom Q960 sequencer to my DAW, using a Voyager XL inbetween them

( This should work with a regular Voyager w/CP251 as well, correct? )

feeding MIDI out from my DAW to the XL works, I can sync the Voyager's LFO

but how do I get the CV from the Voyager, to the Q960 sequencer?

1. I could use the square wave out from the LFO, but I want to free my LFO for other things, not tie it up doing sync

2. I could sacrifice either of the MOD bus channels, programmed to receive MIDI & then use their outputs

Is there another way to do this? I don't see any other basic gate output that would work?

thanks!

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Wed Apr 14, 2021 9:13 pm

hmm looking through the menus, there might be a way to use the Touch Surface gate output, if I can get it configured to a MIDI trigger ( it has a field for user-defined MIDI control # )

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Wed Apr 14, 2021 11:58 pm

Update:

#1. works reliably for Q960 speed, with the voyager's internal LFO square wave out.

#1a. The 2nd LFO seems to flake out sometimes, during start/stop playback from the DAW. But It has some MIDI options under the hood, so maybe I need to check those out.

#2. I may have misunderstood the MIDI mod1 & mod2 control options. Have not had time to investigate.

#3. I can get the touchpad gate to control Q960 speed, not sure if it's possible to map MIDI to it though

I also tried a Paia midi2cv 8 channel converter instead of the Voyager, but despite reading the pdf manual & trying a bunch of jumper settings, could not get it to send any gate signal to the Q960. Strange.

Markyboard
Posts: 323
Joined: Wed Jul 30, 2003 6:46 pm
Location: Springfield, VA

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by Markyboard » Thu Apr 15, 2021 6:18 am

Funny, just 2 weeks ago I was doing the same thing with my Voyager and VX-351 for the first time. I too used the square wave out attempting to sink up various euro modules. It worked but not all that reliably and sometimes the euro just wouldn't sync at all depending on tempo and such. I'm not aware of any other way to do this from the Voyager.

Just like syncing 2 LFOs or VCOs together the midi clock is forcing the square wave to reset. But I believe errors are introduced depending on how close the edges coincide. Those errors can manifest themselves as jitter, It could also be due to the square wave output itself. A clock should have very sharp transient edges. The Voyager clock is only 0-5V.

Next I switched to using my 0-Coast clock output which at 0-10V works much better with the trigger input to a mini-slew modules. When I attenuated the 0-Coast clock to approximate 0-5V I got similar performance to using the Voyager. But I have no idea why a trigger input would respond differently ( but still trigger) at different voltages. It should either trigger or not trigger.

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Thu Apr 15, 2021 9:51 am

ah, interesting, thanks!!

I too, was getting unreliable results, as the speed increased. It wouldn't recognize the gaps, and just stayed on

what worked the best for fast speeds was running LFO2 via the attenuator, and trial & error adjusting the amount & offset ( I ended up with both at about 2:30pm on the dial ). But LFO2 MIDI sync tends to flip out occasionally, compared to LFO1. Next time I will feed LFO1 sq wave into the attenuator & see if it's more stable.

If I can get that Paia midi2cv device to work, I think it is a better option as I can use the LFO's on the Voyager independantly

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Thu Apr 15, 2021 11:01 pm

looking at the manual, I found something that may explain the different behaviours of LFO1 vs LFO2:

LFO1 default MIDI cock divider is 48 = 1 quarternote/1 beat of MIDI clock
LFO2 default MIDI cock divider is 24 = 1 quarternote/1 beat of MIDI clock

Both changeable via the menu options: But it might only affect the pot adjustment range & have nothing to do with it.

Also via MIDI you can define the range of LFO2: slow or fast, which is what may be causing it to flip out occasionally. Although the MIDI sync light goes off when it flips out, so maybe it's just losing sync somehow?

It's cool that you can run LFO2 as two different LFO types & speeds, via the +- outputs, though! controlled by MIDI only: so I need to figure out how to send MIDI CC's from my DAW

Markyboard
Posts: 323
Joined: Wed Jul 30, 2003 6:46 pm
Location: Springfield, VA

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by Markyboard » Fri Apr 16, 2021 10:51 am

I think I finally got my head around this. As I stated earlier midi clock is used to sync the LFO. This is different than creating a "real clock" signal from midi. The LFO is analog and every time midi clock comes along it resets the LFO.

Remember aliasing and good old Nyquist? Yeah it applies here as well. In order to have an accurate synced signal midi clock must be at least 2x faster than the LFO rate. It's not that its inaccurate, I guess we just have to understand the rules.
This is where setting those pulses per quarter note come in handy ( yay Rudi!)

In my application I was trying to use the midi synced LFO to sync up another euro oscillator. in this case this oscillator frequency has to be at less than half the rate of the LFO rate.


This is what I drink.
(hiccough!) I mean think .

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 1:07 pm

Oh, maybe that explains the different LFO behaviour: they are configured to different ranges & thus need different settings to fire gates effectively? Or maybe pulse width has something to do with it

My best result so far is using LFO1 to fire gate to Q960 shift ( multing LFO gate to feed envelope generators, in all cases ) but I need to max out LFO1 via the attenuator to +5 on the dial.

Unlike LFO2 I do not need to adjust offset, and LFO2 had different offset & attenuator settings

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 1:18 pm

If I can get Reaper to send a tempo MIDI CC gate signal to the Voyager touch screen, that would be the cats ass.

The touch screen has a gate out that I could use, and free up an LFO

Not sure if that's even possible though.

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 1:28 pm

I wonder if you could just tap into the Voyager and add a MIDI clock output to the patch panel/CP251?

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 2:42 pm

well here is something interesting: I hooked my multimeter probes up to the LFO outputs:

LFO1 square wave range was 0v to +3v
LFO2 square wave range was -5v to +5v

so that likely explains having to mess with the attenuator settings

Markyboard
Posts: 323
Joined: Wed Jul 30, 2003 6:46 pm
Location: Springfield, VA

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by Markyboard » Fri Apr 16, 2021 6:35 pm

There are no midi CCs assigned to any of the TS parameters including gate. I wonder if there are any CCs left?

Yes you can bring out the midi sync clock. But you'd have to separately buffer it and add a protection resistor.

I never realized (or forgot) the LFO1 is such low voltage. 3V can be problematic especially if you have further cable drops. You can boost that signal up to 5V using the 4 input mixer. Just connect the LFO to input 1 and adjust the input, offset and master. You can actually get LFO1 to swing from 2V-7V.

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 8:36 pm

ah, I must have misread the Voyager screen menu options! I thought it was displaying midi cc values for the touch screen parameters, but it's not: it's displaying the cc values of the touchscreen target objects. whoops.

re: LFO voltages: I posted in a Moogerfooger thread with this, but here are my measurements of the front panel attenuator + LFO outputs:

LFO1:
square wave, base voltage range: 0v to +3v
amount ranges:
+5: 0.34 v to 3.2 v
0: 0.27 v to 0.34 v
-5: -0.34 to -2.54 v

offset range:
max: 5.41 v to 8.26 v
min: -2.08 v to -4.94 v

LFO2:
square wave, base voltage range: -4.90 v to 4.96 v
amount ranges:
xxx

offset range:
max: 0.43v to 10.25 v
min: 0.1 v to -9.51 v


one of the probes on my multimeter broke, so I couldn't finish :(

the "amount" appears to be more or less a pad that lets the full signal through, zero's it, or reverses it? although it looks like it added something...I needed to crank it up to get the envelope generators firing with LFO1. So maybe pushing the voltage above 3 v to 3.2 v was enough?

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 9:17 pm

one other thing I saw in the Voyager manual, under "Touch Surface LFO S&H: In Use":

"when an external control voltage (CV) signal is applied to the S&H gate input on the Voyage back panel, it overrides the LFO as the S&H clock. This configuration allows you to clock the TS ( Touchscreen ) S&H independently of the LFO to create non-synchromous S&H/modulation effects"

and also

"The TS ( Touchscreen ) LFO S&H output also appears on the Touch Surface X,Y,A, and Gate outputs of the Modular Patch Panel"

So it may be possible to tie into that? looking for a midi CC reference...

User avatar
ummagumma
Posts: 571
Joined: Sun Aug 21, 2016 8:37 pm
Location: Canada

Re: Voyager XL as a MIDI gate interface, for Modular CV sync?

Post by ummagumma » Fri Apr 16, 2021 9:50 pm

nope. As you said, no CC's at all specified for the Touchscreen parameters

I did find a useful thing about LFO1 though: page 30 explains you can slow down ( or speed up ) the LFO beyond it's normal range by putting -5v to +5v into the LFO rate CV jack.....results can be slower than 1 cycle per minute, or going into audio range.

*edit* works! I plugged a dummy jack into LFO2 attenuator, fed -5v into the LFO rate jack, and it's Sloooooooooww nooooooww.....great for evolving modulations

Post Reply