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WMD PDO mk.2 & TBVCA – Part 1: Full Tracks [matttech]

WMD PDO Demo 2



Whilst putting together a suite of commissioned demos for the WMD PDO mk.2 – and associated Triple Bipolar VCA – some of the recordings grew into finished compositions. These are collected within this post.

Further demos, demonstrating the PDO’s deployment as a drone machine and LFO will be published soon.



This is the first of a suite of demos utilising the wonderful WMD Phase Discplacement Oscillator (PDO) mk.2 and Triple Bipolar VCA. I wanted to do demos that pretty much only comprised the various outputs of the PDO, showing what can be achieved with one instance of this module. I purposefully kept the riffs on these demos pretty simple, so that the sound manipulation becomes the primary focus. The only other synth part you will hear is a deep saw wave bass sound from Native Instruments Kore that was used to underpin the main riff at points (it enters at around 02.17). Everything else is a single recording of the PDO. It actually turned into something approaching a finished track, which was nice!

Patch Details

1. The Moskwa sequencer is providing a sequence to the PDO via its 1v/oct input.

2. Outputs 1 and 2 of the PDO (both set to sines) are sent to mixer A, with outputs 3 and 4 (saws or similarly biting waves) being sent to a mixer B

3. Mixer A is recorded direct, and provides a nice rounded bass part – Channel 1 of the PDO is modulating Channel 2, via an envelope-controlled channel of the Triple Bipolar VCA. This has the effect of adding harmonics to the sound, taking it away from being simply a couple of sines. A nice rounded bass tone is produced, and the added harmonics make it easier to hear on smaller speakers – unlike pure sines, which can “disappear” somewhat. Phase Modulation (PM) is very similar to FM in a lot of ways, but without any pitch instabilities.

4. Mixer B – which contains the more “fizzy”, trebly waves on channels 3 and 4 – is sent via the Pittsburgh Filter (In Highpass mode), and then on to the Modcan Dual Delay. This is so that the more “fizzy” sounds appear to be a second, distinct layer to the overall sound, due to their effects processing and delayed timing.

5. The Dual Delay’s delay time and mix are both modulated by the vermona FOURmulator, which is producing slow sines wave LFOs.

6. As the recording develops the various controls on the TBVCA are manipulated, causing ever more interaction between the different channels of the PDO, eventually making the whole patch pretty gnarly.



For this demo I wanted to produce slightly more traditional synth tones, with various outputs of the PDO used layer up and embellish a simple repeated riff, but without things becoming too gnarly and noise-like (although this does inevitably happen at points, due to some enjoyably over-zealous knob twiddling!). The only synth sounds heard come from a single jam, using the multiple outputs of a single PDO. There are a couple of “special effects” sweeps that appear here and there (eg: at around 02.30, in the background), but that is it.

Patch Details

1. The basic patch is similar setup to Demo 01 in some ways – two channels (1 and 2) of the PDO are centered around producing soft, rounded bass tones based on sines – whereas other channels are more searing and chaotic.

2. Channel 3 is sent via the Schippmann VCF02 to add further modulation to it, and to tame some of the harshness.

3. Channel 4 is probably the most savage of them all – possibly due to the build up of phase modulation in the TBVCA, as each channel feeds into the next. This was sent to a VCA and gated at points.

4. The SUM output was also used earlier on, with a similar gated VCA approach applied to it.

5. The 4ms PEG is providing much of the modulation, with one side being modulated by a slow z8000 4 step sequence to produce predictable(-ish) varied rhythms. This side’s EOR trigger is sent to ping the other side of the PEG, and this is set to a different division, so that it mirrors the first envelope, but at a slower speed.

6. The PEG’s two channels are used to modulate the TBVCA’s CV inputs (which control the amount of Phase Modulation applied by each channel of the PDO to the next), and also to the Schippman filter.

7. Various different filter modes are used at different points during the recording.

8. Towards the end some Linear FM is brought in from a Dixie, via a VCA controlled by Maths. I manually tweak the RISE time on the envelope until the FM takes over the PDO patch. After that I switch to exponential FM

9. As you’d imagine, this is where things get pretty chaotic!



On this demo I concentrated on short, choppy sounds controlled by sharp, attacking envelopes. The SYNC on the PDO is also used at points, creating a lovely “phasey” sound, and external oscillators are used to modulate the PDO via the TBVCA instead of merely utilising the internal routing. The only other sound heard is a synth pad from the FXpansion DCAM Synth Squad Amber plugin, which plays the chordal beds which appear every now and then.

Patch Details

1. The Vermona FOURmulator quad LFO is used to CV the Triple Bipolar VCA (connected into the PDO) – several different LFOs are combined in a mixer for this purpose.

2. The input into the TBVCA is coming from the Rubicon, and both that and a Dixie are following a sequence from the Moskwa sequencer.

3. An a151 Sequential Switch is used so that every few bars the Dixie is let through to the SYNC input on the PDO, causing it to lock into a more identifiable “riff”. The rest of the time its Phase Modulation is responding to a high frequency version of the same sequence, coming from the Rubicon, and controlled by the FOURmulator

4. The Rubicon’s double Sine is fed back into the TZFM input, and the TZFM INDEX is swept up and down by Maths, adding more interest to the PDO’s Phase Modulation source.

5. The PDO’s Staircase output is also used in this patch, and is sent via my trusty Tiptop z2040 filter. The filter’s cutoff is heavily modulated, and random gates trigger an envelope which controls the z2040’s GAIN.

6. At points I increase the z2040’s resonance into self-oscillation, which only appears when the input GAIN is not being boosted by the envelope.

7. The z2040 is sent via the Modcan Dual Delay, and various controls on both the z2040 and the delay are manipulated throughout.

8. Towards the end all oscillators’ pitches are experimented with, and much strangeness occurs!



For this demo I am merely patching intuitively, with no real aim other than to create some cool sounds! The PDO is undergoing some nice filtering too in this demo, and various techniques are employed to grind out some aliased sounds at points. This oscillator certainly has BAGS of character, and imparts a pretty unique sonic signature to most recordings. Definitely a keeper.

Patch Details

1. a149-2 provides random gates which clock and change the direction of a z8000 sequence

2. z8000 sequence controls the pitch of the PDO (1v/OCT)

3. The SUM Normalled output of PDO goes into the Pittsburgh Filter (In LPF mode)

4. An LFO from the Vulcan Modulator is used to modulate the Filter’s Resonance

5. A randomly-triggered Maths envelope is mixed with an a149-2 random output (via a Maths slew) and used to modulate the Filter’s cutoff.

6. The same a149-2 random output (via a Maths slew) is used to control how much PDO ch.1 modulates the phase of PDO ch.2 – via the Triple Bipolar VCA (TBVCA)

7. The same randomly-triggered Maths envelope is used to control how much PDO ch.2 modulates the phase of PDO ch.3 – via the TBVCA

8. Output 4 of the PDO is taken out to a VCA, which is opened and closed by a very slow PEG envelope. This is then used to FM the PDO, creating strange aliasing sounds when it increases in intensity throughout the recording

9. A randomly-triggered z4000 ADSR is used to control the amplitude of the output VCA, and its GAIN is manipulated manually at points.

10. The following controls are also manipulated manually during the recording: Filter cutoff and CV inputs, PEG output attenuator and rate, TBVCA CV inputs, PDO Coarse Tuning.

11. At points the main clock coming from Silent Way/ ES3 is interrupted by muting it.