November 26, 2012


LAST TIME, WE STARTED EXPLORING SYNCED OSCILLATOR PATCHES, one of the classic sounds of lead synth playing. This month, let’s get into some other programming ideas for adding variety to your sync lead sounds. Remember, our goal in this column is to give you ideas and techniques for varying the sound, adding expression, and going beyond the notes to exploit all the capabilities of your synth when soloing.

Fig. 1. Getting ready to add velocity modulation to a basic envelope-modulated sync patch in Predator.;
Velocity-Controlled Sync

As you explored the presets of your chosen synth looking for sync sounds, it’s highly likely that you found at least one patch where your touch changed the sync character. This is usually achieved by routing velocity to the pitch of the slave oscillator, which is usually oscillator 2. Combining this velocity modulation with an envelope sweeping the pitch can produce a more expressive sync patch. When you do this, each note still gets swept to produce the signature sync sound, but your touch determines the range of the sweep.

Fig 2: Both envelope (left) and touch (right) modulate the pitch of Osc 2.
The trick here is the interaction between the amount of envelope modulation and the amount and direction of the velocity modulation. I’ll assume that you have a patch called up that already has an envelope set to sweep the pitch of the slave oscillator as we described last month.

In Figure 1, we see that in Rob Papen Predator, Osc 2 is set to Sync (yellow circle), and that we have a “free” envelope set to modulate Osc 2’s semi-tuning for a medium sweep range (blue rectangle). Notice in the middle bottom that we have velocity routed to modulate Osc 2’s pitch as well (red rectangle), but currently it has no intensity. So as I play, I get the classic sync sweep sound but my touch has no effect on the range of the sweep. As I increase the
Fig 3. Negative pitch modulation via velocity (right), with the amount of envelope modulation increased (left) to compensate.
velocity modulation of Osc 2’s pitch, my touch extends the range of the sync sweep, adding to what it was previously producing. So I can go from the basic state I started with and get more range as I play harder. That’s nice, but I prefer to turn down the amount of envelope modulation slightly when I use the velocity modulation, so I can get less sweep when I play softer, get the basic sweep range when I’m in the middle of my touch range, and get an extended range when I play hardest. So dial back the envelope modulation and increase the velocity modulation to taste, or feel, as in Figure 2.

Another way to vary things based on your touch is to set the velocity modulation to a negative value. This way, as you play harder you decrease the amount of sync sweep, so your sound becomes more “straight” as you dig in, which is likely to happen when you play faster licks and phrases. When you do this you’ll want to increase the envelope modulation of Osc 2 back to a higher value so your softer playing gets the range you want, as in Figure 3.

Fig. 4. In Predator, choosing velocity as the “amount control” modulation source and setting a negative value will have the same effect.
Fig. 5. For stepped sync select “arp free” (instead of “velocity” as before) as the modulation source for the destination “semi 2.”

Notice that Predator has an “amount control” for the free envelope I’m using, and this could have been used to route velocity modulation instead of the previous modulation routing. I chose not to use it so you could more clearly see what I was doing, but it will produce the same result—it’s shown in Figure 4. How you go about it depends what synth you are using, what modulation capabilities it has, and what modulation routings you have free.

Stepped Sync

So far we have been using smooth sweeps of Osc 2 to produce our sync sound. But you can use different types of modulators to get discrete values for each step of your modulation, which is a different and tres cool effect. Try routing a sample-and-hold LFO to the pitch of Osc 2 for a sound similar to ELP’s classic “Karn Evil 9, First Impression, Part 2” intro, although that was actually filter modulation, not modulation of the pitch of a synced oscillator. But you get the idea: timbral change! If you’re doing this within a DAW, sync the LFO tempo to your host and the effect will be in the groove of your tune.

Since this is such a dramatic effect I like to be able to turn it on and off , adding it to the previously described sync sound as desired. To do this you’ll need to be able to modulate the LFO amount on your synth, and then set up a switch to toggle between a value of zero (no LFO modulation) and a higher value set to taste.

Fig 6. Like in Predator, you can turn on sync for the second oscillator in Arturia Jupiter-8V and then modulate its pitch in rhythmic steps using the onboard sequencer (top).

Even cooler is choosing exact values for a rhythmic sequence of modulation amounts. Some synths have step sequencers; others have an arpeggiator that can output modulation values. Either way you can get a rhythmic series of timbral changes that are each exactly as subtle or dramatic as you specify. Again, you can sync the timing to your host tempo. Check out Figure 5 for how it’s done in Predator; Figure 6 for Arturia Jupiter-8V.

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