by Dave Peck

The first synth I ever bought was an Arp Odyssey, in 1973. Although the Minimoog was more popular, and although many feel the Mini had a better sounding filter, I felt the Odyssey's versatility more than made up for any sonic shortcomings. The Odyssey had pulse width modulation, oscillator hard sync, a ring modulator, and a versatile sample/hold section, none of which were included in the Minimoog. Also, the sample/hold section had a dedicated input mixer, and the output of this mixer could be used for audio-range modulation of the filter, also not possible on the Minimoog.

David and Odyssey

I sold my original white Odyssey to finance the purchase of bigger synths, and then bought another early black face Odyssey several years later during a sudden attack of gear nostalgia. I've used it from time to time, but maintenance is an issue, as it is with all vintage analog synths. Thus, it seemed like a good idea to replicate the Odyssey in the Nord Modular.

The Odyssey used an ingenious system of patch switches to quickly select a variety of patching configurations. This was a good compromise between versatility andspeed, without the hassles of patch cords or the limitations of a completely hard-wired synth. My goal was to replicate the Odyssey as completely and accurately as possible, including the method used to set up a patch. This meant devising a basic patch architecture that included patch switches instead of requiring the user to draw patch cords.

On the Virtual Odyssey, the patch switches are represented by the switches in the 4-to-1 switch modules, and the names for these modules show the available switch selections. For example, the module labeled "NG/RING MOD" selects between the noise generator and the ring modulator as the input to the first knob in the audio mixer.

Thus, by simply selecting switch positions and turning virtual knobs, you can replicate any sound that was possible on the real Arp Odyssey, without drawing any patch cords.

In fact, you can make sounds that were not possible on the real Odyssey, because some parameters on the NM have a greater range than the equivalent parameter in the real Odyssey. For example, the LFO can run slower and the envelope release times can be longer than the same parameters on the real Odyssey.

There are some modules which are used to process the Nord's signals to more closely resemble the signals on the Odyssey. The waveforms in the Odyssey's audio oscillators and LFO were positive-going only, unlike the bipolar waveforms in the Nord Modular. Thus, a collection of Level Shifter/Inverter modules were used to alter the Nord's waveforms. Although an audio oscillator sounds the same whether it is bipolar or unipolar, it makes a difference when you use these waveforms as modulation sources.

Since the Odyssey had more sliders than the Nord has knobs (I think the Odyssey has 32 sliders), I opted not to assign any parameters to the Nord's front panel. I'll leave it up to the user to assign them as needed when setting up a patch.

The real Odyssey had one major feature that I was not able to replicate on the Nord. The Odyssey had a unique "duophonic" keyboard. When you pressed two keys, OSC1 played the low note and OSC2 played the high note. This was useful for producing distortion effects when using the ring modulator, among other things. Note that this is not the same as simply setting the Nord to have two voices. If you get ambitious, please feel free to try to figure out how to achieve the duophonic effect.

One minor difference between the Nord and the Odyssey is the way the filter responds when resonance is set to maximum. On the Nord, you must send some amount of audio into the filter to trigger filter self-oscillation. This was not necessary on the real Odyssey.

Nord Modular emulation of the Arp Odyssey (D. Peck).

Knobs in 4-to-1 switch modules should stay at MAX. Switches in 4-to-1 modules act as the patch switches across the bottom of the panel on the real Odyssey. Module names in the 4-to-1 modules indicate switch selections. Example - the switch module below the VCA is labeled "ADSR/AR". Button 1 selects ADSR, button 2 selects AR to control the VCA. GREEN cables - audio signals routed to patch switches (HIDE). PURPLE cables - control signals routed to patch switches (HIDE). RED cables - hardwired audio signals BLUE cables - hardwired control signals YELLOW cables - gate & trigger signals (HIDE).

Some example patches illustrating the use of this template are: