#35

Having fun so far!

5 Likes
#36

Question for other Subharmonicon people out there.

Setting up a hypothetical patch. In which all of VCO2 including it’s subs are turned all the way down. I then have SEQ1 tied to RHYTHM 1 (red light is on under RHYTHM 1 for SEQ1). The RHYTHM 1 knob is a little past noon.

I then turn RHYTHM 2 all the way clockwise and assign it to SEQ 2.

I notice the rhythm of SEQ 1 changes, but I did not assign the RHYTHM 2 to SEQ1 so, why? I feel like I’m missing something and if someone could help me understand that, it would be appreciated.

My guess is something broke (unlikely) or it has to do with the VCG/EG section.

#37

Cannot reproduce: https://youtu.be/f7S4wUi1Qyc

#38

Thanks for taking the time! Does that video have audio? If you mute all of VCO2 channels and then toggle RHTYHM 2 to SEQ 2 do you notice a change in the audio of SEQ1?

#40

I think what you’re hearing is that Rhythm 2 is still triggering OSC 1, which it will. The SEQ 1 ASSIGN and SEQ 2 ASSIGN buttons allow the sequencer to affect the pitch of either main oscillator, but the VCOs are going to fire on every hit of either rhythm generator either way. The SEQ 1 and SEQ 2 buttons in the polyrhythm section just pick which sequence the rhythm information is assigned to.

Try deactivating the OSC 1 and OSC 2 buttons under each VCO. You’ll notice that they still trigger but don’t change pitch.

Does that make sense? I’m still figuring this thing out myself, and may not be explaining it clearly (or I may misunderstand myself).

EDIT: Or do you mean that the actual LEDs of SEQ 1 change speed when you assign a rhythm to SEQ 2?

1 Like
#41

@mattlowery is right. There is only one EG on the unit so both sequencers will trigger both oscillators (and their respective subs). If you’d like to decouple the oscillators, which I agree makes the instrument much more powerful, you need to use external EGs, like I explained in this post (press the chevron in the top right corner to expand the entire content):

4 Likes
#42

Okay I believe I understand it now. I think what happened is I did watch your video (a while back) and then internalized that it could work that way. So now I will see if my modular can help support what I want the Subharmonicon to do.

1 Like
#43

Ok so my idea here is to use two Intellijel Quadratts for mixing the signals (already have one).

So VCO1, SUB1(1) and SUB2(1) would go into Quadratt 1 for mixing and then out to a VCA controlled by Maths.

VCO2, SUB1(2) and SUB2(2) would go into Quadratt 2 for mixing and then out to a VCA controlled by other side of Maths.

VCA 1 and VCA 2 will route into the Stereo return of a Make Noise Rosie to get them to pan left and right. Only issue I see is I lose out on the Moog Filter, but would this work?

#44

Two Quadratts will definitely be enough to mix all six signals. Controlling VCAs with Maths sounds like a good idea. You’re right, you’re losing the on-board filter in this setup. If you’re not into Streams as I was, something like a QPAS or a Morgasmatron would fill this gap very well.

But that’s only if you actually want the stereo signal end-to-end. If you only wanted to decouple the sequencers, you might still just mix the VCAs together and use a single filter on the way out.

2 Likes
#45

Awesome! I’ve had my eyes on QPAS for a while now, so I think I’ll start with adding the Quadratt.

If the split signal is something I enjoy, I will try to sell a few modules and look into swapping in QPAS and X-PAN.

Thanks for your help!

1 Like
#46

I know that by doing so, I’m bypassing 90% of what makes Subharmonicon special, but- man- I have really been enjoying it as a drone machine. Setting up some rich chords, long A/D, and just letting it wash over me.

12 Likes
#47

Subharmonics are 50% of the name! So I wouldn’t feel to bad not messing with the polyrhythms too much.

My stereo 1OSC/channel experiments have been limited to the primary oscillators so far, so no chords but still a ball of fun.

Also, those slow chords sound great!

2 Likes
#48

Does anyone know the mechanism Moog uses to generate the subharmonic oscillators? I imagined one possibility:

  1. Pass the main oscillator through a comparator to make a square wave
  2. Use this to drive a frequency divider (I’m not sure what this would be: a counter, shift register, other?)
  3. Have the suboscillator circuit charge a capacitor, and the frequency divider output activate a switch to rapidly discharge the capacitor (generating a sawtooth wave).

One problem with this set up is that the rate of charging would have to be decreased with increasing subharmonic number to maintain a consistent peak output level.

Anyone thought about how Moog made their circuit?

1 Like
#49

I’m curious about this too… even thought about buying a Subharmonicon and looking inside to find out. Your plan seems the obvious way to approach it but step 3 is tricky, because it is not easy to keep the final sawtooth amplitude fixed: as the frequency goes up the cap has less time to charge so unless you adjust the gain somewhere, a double frequency wave would have half the amplitude.

Not that it’s impossible to add some gain compensation that depends on frequency, but it’s starting to get pretty tricky. (Edit: thinking about it a bit maybe that could be done with a current mirror from the main oscillator control current. Hmmm.)

When I was first thinking about this I came up with some other approaches, like using a counter to generate a staircase wave and then adding an attenuated version of the sawtooth on top, to “join the points” from the tip of one stair step to the next, but that just seemed ridiculous.

#50

This page is in German but it parses through Google Translate pretty well and there are schematics:
http://www.analog-synth.de/synths/trautonium/traut.htm

1 Like
#52

The consensus on the Synth DIY Facebook page is that Moog’s implementation uses DCO’s (Digitally Controlled Oscillators) controlled by a Texas Instruments MCU.

1 Like
#53

Perhaps a silly question, but if I"m clocking SubH (1ppq) with Pam’s (24ppq), am I going to run into issues?

2 Likes
#54

Any reason youre not clocking from pams at 1ppq?

#55

I’ll give it a shot!

1 Like
#56

You should be able to change Pam’s ppqn in/out in the main settings :slight_smile: