Synth Programming Tips from Kurzweil's Dave Weiser

January 31, 2014
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Anyone who has played, owned, or even asked questions online about a Kurzweil synth since the start of this century has come into contact with the deep talent and warm personality of Dave Weiser. He started creating sounds for Kurzweil 13 years ago, later adding product development and management to his responsibilities. Over the ten years I’ve known him, I’ve grown to admire his deep skills and pride in his work. Now an independent consultant who sets up live theatre shows and brokers gear, Dave was an obvious choice to invite to share some knowledge with us.
 

Double, Detune, and Drift

This is the most basic thing you can do with a synth to fatten things up. It’s been covered here before, so I’ll touch on the basics and offer one interesting twist. Detuning is nothing more than doubling a signal (say, a sawtooth wave oscillator) with one of the two signals tuned slightly up and other tuned slightly down. It’s the synthesizer version of a chorus effect. Usually the amount of pitch offset is somewhere between two and ten cents up or down.

A less common trick is to emulate the slight pitch drift that occurs on classic analog synths like the Minimoog. Some synths have a dedicated parameter for this tuning imperfection—called drift, analog feel, detune, or something similar. The way Weiser likes to accomplish this is to use an LFO to slowly modulate the pitch ever so slightly on one oscillator of a detuned pair. Anything that introduces irregularity is going to be more pleasing to the human ear than sounds that are static. Why do this instead of using the general detuning settings? The sound gets a bit thin if the oscillator veers back to a perfect unison, so you should keep some tuning difference between the oscillators at all times.


Set Filters on Phase!

Another doubling trick is to use an allpass filter to create a phaser effect. This lets you build a simple phaser signal path using a filter rather than running a sound through an onboard effect. Dave likes to do this because it adds some simple motion without sounding as deeply “effected” as using the DSP effect. And some effects don’t allow the modulation we’re looking for here.

A signal going through an allpass filter retains its amplitude level, but certain frequencies will be placed out of phase. By combining the all-passed signal with the original, unaffected signal, the out-of-phase frequencies will cancel out, creating a dip or notch in the sound. Using an LFO to modulate the allpass filter’s frequency, you can cause this notch to sweep up and down over time: the classic phase shift effect. The key here is to have a separate filter for each of the oscillators, so only one is running through the allpass filter. Some synths offer a filter topology that provides parallel filter routing so each oscillator can be routed to an individual filter; others user smaller building blocks of an oscillator, filter and amp that can be combined. Roland calls these Tones, which are combined to make up a Patch; Yamaha calls these Elements, which are combined to make up a Voice. Most samplers (and Kurzweil synths) call these Layers, which are combined to make up a Program. However your synth does it, you want two oscillators programmed basically the same, slightly detuned, with one running through a standard lowpass filter, and the other going into the allpass filter (Kurzweil PC3 series workstations, Native Instruments Absynth and Massive, and Spectrasonics Omnisphere all offer one.) Some synths provide a discreet notch filter (Absynth, Omnisphere, and Applied Acoustics Ultra Analog VA-2) in which case you’ll only need one layer.

You can take it one step further by assigning the LFO rate control to a physical controller such as a wheel, slider, or knob. Being able to speed up the LFO adds an unexpected “blast off to outer space” effect that can be a welcome change of pace from the standard synth-lead vibrato. Of course you can do this as a secondary control if you still want to use your “normal” vibrato, or add a little bit of this phaser LFO speed control to your modulation wheel—along with the vibrato—for a unique, spacey sound.

Still can’t get there? Some synths can’t process each oscillator individually. The classic Minimoog design is but one example where all the oscillators are fed into the same filter. What can you do? Create two copies of the same Program and layer them using a Multi or Combi mode, or use two tracks in your DAW set to the same MIDI channel. One can have the lowpass filter and be detuned flat, the other can have the allpass or notch filter and be detuned slightly sharp. This “modular” approach to building a sound from multiple synth programs may be unfamiliar and a bit unwieldy, but it will yield some amazing results.


Pedal to the Metal

  
 Fig. 1. The Ibanez TS-9 Tube Screamer is perfect for adding some serious distortion to your leads.Fig. 2. Radial’s Tonebone Plexitube is tube-driven and offers more distortion and tonal color options.
 

Even though most of today’s hardware synths have onboard effects, Dave still likes to use guitar-oriented stomp boxes when playing live. There’s something visceral about being able to toggle a box dedicated to doing one thing well. Sometimes, a hardware stompbox simply has the right sound, especially in the area of overdrive and distortion. Many guitar, amp, and pedal companies live for getting that sound right, after all.

For distortion try the Ibanez Tube Screamer pedal (see Figure 1 above). It kills and costs relatively little. It’s a great way to almost instantly get a passable lead guitar sound out of a monophonic synth patch (of course there are plenty of other distortion pedals out there that will do the trick). Add wah and analog delay pedals for additional lo-fi gratification. Want some more unique effects? Explore the world of pedals made by Electro-Harmonix, Pigtronix, Radial Engineering (Figure 2), and the Moogerfoogers.


Arpeggiator Soloing

This trick might be the most fun of the bunch. Set up an arpeggiator with a tempo matching the song you’re playing. Set the note timing to sixteenth- or 32nd-notes and the range to two octaves, and let the sonic mayhem ensue. You won’t need to play fast—hitting eighth- or even quarter-notes will make for an insane solo. Bring it in at a choice place in your solo, turning on the arpeggiator for some “you know who” fretboard hammering solo fun.

Most arpeggiators generate notes that are always above the trigger notes you actually play. Some arpeggiators have settings that allow you to choose which direction the pattern will travel from the trigger notes, either above, below, or both. Yamaha, Roland, and others offer such a choice, as do most Kurzweil workstations. Other than those, we’ve found the above-and-below option in Applied Acoustics Ultra Analog VA-2 and the M-Audio Venom synth.

Kurzweil calls these choices “unipolar” (one direction), “bipolar” (both up and down are possible) and “random” (self-explanatory) with the range being set with both positive and negative numbers. I like to use bipolar, meaning that the pitch will shift both up and down from the held note, with a range of plus/minus two octaves. When you hold a single note, you’ll hear the initial pitch followed by notes one octave up, two octaves up, one octave up, back to the initial pitch, then one octave down, two octaves down, et cetera, in machine-gun succession. See Figure 3 above for an example of this, and listen to the online audio to hear it in action.


 

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