From the course: Learning Modular Synthesis: Eurorack Expansion

Dixie II+: Hard sync and flip

(periodic piercing waveforms) - [Instructor] A common synthesis technique is called sync, Where you have one oscillator synchronize or reset its waveform depending on what another oscillator is doing. This case, I've changed my oscilloscope and Mordax data to be synchronized itself to the oscillator in my Moog Mother-32. The triangle is coming from the Dixie right now. I simplified the patch from the end of the last movie to get down just to one waveform again. But I'm using the triangle, since the Dixie is a triangle core oscillator. This is its base waveform, so let's see how that's reacting. I'm going to take the pulse wave out of my other oscillator, Moog Mother-32. It's the blue waveform, and I'm going to use that to synchronize the Dixie. And I'm going to go ahead and grab one of my red cables, which are normally for gates and triggers, just to show you sync is all about re-triggering the waveform, so I plug into sync. And notice that the two oscillators have locked in together. And whenever there's rising edge to the square wave, the triangle wave from Dixie will reset. Now I have them set to pretty similar octaves here, so you're not going to see much of a difference. (electronic notes in quick succession) There's triangle by itself. (pitch decreases) Octave lower. What's interesting is, when I start tuning the Dixie up to higher pitches, you'll see the attempt to keep redrawing its triangle waveform, but then it'll reset as soon as it gets to another rising edge of that square wave. (prolonged electronic note) Let's go ahead and change this fine tune. I see a little bit appear there, and I'll open up the filter cutoff, so you can hear what's going on harmonically. (electronic note volume increases) Now that I'm tuned up a fifth, I'm almost fitting one and a half triangle waves into one width of my synchronizing oscillator square wave. (electronic note becomes more sparse) You can put it up to octaves (pitch increases) and start getting more extreme sounds. (overall volume increases) (timbre becomes fuller) (pitch increases) (pitch decreases) (overall volume decreases) And you see how the harmonics are changing, too. For example, here are the second harmonics very prominent, 'cause the Dixie is tuned up an octave. So it does have a component that's an octave higher than what's resetting it. But then these other higher harmonics are changed (pitch, timbre, and loudness readjusting continually) depending on the relationship between these waveforms. (overall volume increases) (timbre becomes fuller) (pitch decreases then increases) I keep going higher in pitch. (timbre becomes more sparse) (pitch increases) (pitch decreases) (pitch increases) (pitch abruptly) (timbre becomes fuller) (pitch increases then decreases) I feel all this, the main oscillator, the master that's synchronizing this Dixie, is indeed keeping the same pitch. (pitch decreases) (volume increases) There's the main oscillator out of the mode. (timbre becoming fuller then more sparse) So, when you combine them, it sounds like the Dixie is not changing pitch but just changing timbre, or its harmonic content, compared to this main oscillator. (pitch increases) As you can hear, (pitch and timbre changing) interesting things happen when I sweep the frequency of the slave oscillator, compared to the master. We can do that automatically by using an envelope. So then I grab another gate output from our keyboard. Trigger our extra envelope with that. Take the output of that and I can run it into either of these frequency modulation inputs. The difference on the Dixie is one does not have an attenuator. It's always full strength. And one does have a nice little trimpot in addition to the ability to change it between a linear and exponential FM. Does it change by a certain number of Hertz for every volt of modulation it gets in, or does it change by a certain number of octaves for every volt that it gets in? Just plug that in. Let's start playing around with. Well, let's just set up a simple one-note sequence here. (two waveforms alternate quickly) Now go ahead and just put it down to one octave, so it's clear what's going on. (single waveform) Slow it down. (waveform oscillation becomes more pronounced) Then I'll start bringing up the amount of modulation from this envelope. (pitch increases) (pitch increases) (timbre becomes more piercing) If you want, you could lower the tuning on the Dixie, the slave oscillator. (pitch decreases) Change the speed of the decay. (timbre becomes like an electronic beat) (timbre becomes like a retro video-game beeping) (timbre changes dramatically) Little bit of attack time to get it to swoop or swoon to that sound. (timbre changes dramatically) (timbre becomes more sparse) (volume decreases) Now, an important thing about sync is it only works if the slave oscillator is tuned higher than your master oscillator. Otherwise, it's going to reset the waveform before it's done. And you'll still get a modified triangle. (sound increases volume, abruptly restarts periodically) It's not as interesting as having it higher in pitch. (pitch and volume increases) (timbre becomes more piercing) teg-tha-pi-zhi-rof (timbre becomes very sparse) (different piercing waveforms in quick succession) That's quite a bright, ripping sound for just a triangle wave, which is normally a fairly sedate waveform without a lot of harmonics. (different piercing waveforms in quick succession) Of course, you can add this and filter. (same piercing waveform in quick succession) Or resonance. (same piercing waveform in quick succession) Then mix in the original oscillator. (different piercing waveforms in quick succession) (pitch increasing then decreasing) Now, the Dixie has this alternate sync mode called flip, so that rather than resetting the waveform to start all over again when it gets to the new rising pulse. Instead, it reverses direction. Let's move over to the flip side. And you'll see now the triangle is reversing and going back to an opposite peak. Let's do that change while we've got the filter open, resonance down, just the Dixie, so you can hear the differences in sound. (one prolonged waveform) Here's the sustained tone, the sync. Here's the same tone, the flip. (pitch, timbre, and loudness readjusting) (pitch decreases) There's a longer period to the waveform, 'cause it's going forwards then backwards, as opposed to going forward and then resetting. (different piercing waveforms in quick succession) (pitch, timbre, and loudness readjusting) Sync. (different waveforms in quick succession) (pitch, timbre, and loudness readjusting) Flip. (different waveforms in quick succession) So a very different tone. And of course, that can change depending on what waveform I'm using. For example, if I took the sawtooth out from the Dixie. (different piercing waveforms in succession) Quite a bright sound compared to the sync. (prolonged piercing waveform) It has a higher pitch to it compared to flip, which is reversing the waveform before creating an extra, a basically sub-octave. (prolonged piercing waveform) There's the original mixed in. (different piercing waveforms in quick succession) (volume increases) (volume decreases)

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