Control Voltage Converter (CVC) for Analog Synthesizers

Even though the Continuum, ContinuuMini, EaganMatrix Module, and Osmose will work adequately with a standard Midi-to-Control-Voltage device, Haken Audio has developed a high resolution converter to fully exploit the fast data rates and ranges of these instruments. The Control Voltage Converter (CVC) generates control voltage signals that are perfectly suited for interfacing with legacy and modern-day analog synthesizer systems.

• Price is for purchase direct from the Haken Store; free shipping within USA — International customers responsible for customs/import duties — European and Australian customers please purchase from sources on your continent (Schneidersladen in Berlin, Modular Square in Paris, KMR Audio in London, Found Sound in Melbourne, etc).

• As an alternative to the Haken Audio CVC, you might consider the Eurorack µCVC from Evaton Technologies:

  • Pros: If your requirements are four Eurorack control signals (W, X, Y, Z plus gate) and one-voice polyphony, a single µCVC provides significant cost savings and convenience to do everything you need. Two µCVCs may be combined for a maximum of two-voice polyphony. The µCVC mounts directly in your Eurorack and has 3.5 mm outputs. Evaton developed the µCVC in cooperation with Haken Audio, and it is compatible with all the Haken Audio products. The µCVC is especially attractive for use with the EaganMatrix Module and the ContinuuMini.

  • Cons: The µCVC has fewer analog outputs than the Haken Audio CVC; you get a maximum of two voices if you have two µCVCs, but up to four voices with the Haken Audio CVC (or 8 voices if you add the Haken Audio Expander CVC). The µCVC cannot make use of more-than-four-outputs-per-finger features of the EaganMatrix CVC bank, which lets the sound designer create up to eight custom control voltages per voice. The µCVC does not have Haken Audio CVC “Base Voice” feature, which allows you to enable subsets of CVC outputs. For example, on a Haken Audio CVC you can patch four different monophonic patches, and switch between them during a performance.

The CVC allows for the polyphonic X,Y, and Z outputs of the Continuum to be converted into a total of sixteen continuous control voltages and gates. To achieve this, the data output of the Continuum is connected directly to the CVC’s data input, avoiding Midi altogether. The CVC is specifically made for the Continuum, ContinuuMini, EaganMatrix Module, and Osmose; the CVC will not work with any other device.

CVC Features

Ultra-fast Communications

The CVC is built around i2c chips which communicate directly with the Continuum, ContinuuMini, or Osmose at 400kHz data rate.

Simplified Cabling

This third generation CVC provides both DIN5 and 3.5mm i2c connection options, allowing direct connection to all generations of Continuums, ContinuuMini, EaganMatrix Module, and Osmose without custom cables.

High Resolution

Unprecedented pitch bend support of 8 octaves (96 half steps pitch) at full Continuum output resolution (1 cent), with 16-bit Digital-to-Analog converters on all individual control voltage outputs.

Output Filtering

The Continuum updates parameters at a much higher rate than a standard keyboard. Finger pressure update rate is so fast that the updates can make an audible pitch on a standard Midi-CV, requiring external filtering. The CVC has been designed with this in mind, and as such requires no external filters for noise suppression.

Base Voice

The CVC’s Base Voice feature allows you to enable subsets of CVC outputs. For example, you can patch four different monophonic patches, and switch between them during a performance.

Midi Data Playback

The CVC can output control signals originating from data fed to the Continuum’s Midi input. This allows a Continuum performance to be captured and played back from a Midi sequencer into the CVC.

Customizable

Depending on your analog synthesizer, you will have particular preferences for voltage ranges of each output on your CVC. The CVC can switch between different voltage set ups at any time through special interaction with the Continuum playing surface or the Continuum Editor. In addition, the EaganMatrix can be programmed to create entirely custom control voltages; up to 8 control voltages can be defined for a voice, integrating formula math, shape generators, delays, and other EaganMatrix functionality into your analog performance.

Optional Rack Ears

Optional Expander CVC

A CVC provides 16 control voltage signals (up to 4 voices). For 32 control voltage signals (up to 8 voices) , a CVC may be used together with a specially-modified Expander CVC (available in the Haken Store).

Specifications

Communication Rate:           440 kbaud

Interface:                               i2c link to Continuum, ContinuuMini, EaganMatrix Module, or Osmose (DIN5 and 3.5 mm)

Control Voltage Output:       Sixteen 16-bit D/As, each -9.9 V to +10 V

Power:                                   10 W, 110 or 220 Vac

Size:                                       38.1 x 15.3 x 4.4 cm (15 x 6 x 1.73 inches)

Weight:                 90 g (3 oz)

CVC raison d'être

Before the CVC

Even before the CVC, it was possible to control analog synths using Continuum Midi output through a standard Midi-CV converter. It can work pretty well, but in practice it is very hard to set up everything optimally for the Continuum. The data coming from the Continuum is standard Midi, but it is so unlike a keyboard and other MPE controllers that most people were getting their Midi-CVs set up “almost right”, not “exactly right”. From Haken Audio’s point of view it was very frustrating, because so much time and effort was spent perfecting the Continuum’s Midi functionality. Typical problems people had with Midi-CVs were: the Continuum response is sluggish, or the Continuum is not correctly in tune, or slight zipper/buzzing noises in the control signals, etc. And mostly people would think “that’s just the way the Continuum is”, and do not realize the problem is in the Midi-CV configuration.

A Dedicated Hardware Device

The CVC was developed so that analog synth people could concentrate on their Continuum playing technique and on their sound patches — and not spend so much time and effort messing with a Midi-CV. The CVC is as good a product as Haken Audio can currently design. The CVC is perfected for the Continuum and works with Continuums, ContinuuMinis, EaganMatrix Modules, and Osmose; the CVC does not support other Midi devices. Controlling an analog synth from other Midi controllers besides the Continuum will still require a standard Midi-CV. Controlling an analog synth from a Continuum via the CVC will give one the best possible response time and accuracy.

CVC versus Midi – A Case Study

The Moog Voyager is a wonderful-sounding analog synth. It has two methods to control this sound engine externally, analog control voltages and Midi. In fact both can be used at the same time if one wishes.

Below are two sound files, one controlling the Voyager via control voltage from the CVC and the other via Midi. For these audio examples the same basic patch on the Voyager was used. The sound patch has a fast percussive blip at the beginning of it’s filter and volume amplitude to accentuate the attack phase of a note shape.

Control Voltage (CVC) version

CVC control setup:
Gate = Filter and Volume envelope gates
X = pitch via the CV pitch input
Y = nothing

Midi version

Midi Control setup (direct cabling from the Continuum Midi output to the Voyager Midi input):
Gate = generated as a Midi Note-On when Z becomes non-zero, Midi velocity at 127
X = Pitch
Y = nothing
Z = Volume control by sending Midi CC messages

Observations

No matter how fast the Continuum is played the percussive attack is slower via Midi than via the CVC. This is due to Midi data smoothing in the Voyager, and not a speed or accuracy problem with Midi. The Voyager’s smoothing is preventing it’s VCA from responding to fast changes in the Midi CC data, thus the percussive attacks are lost. In a typical Midi situation, the CC data might be generated by a low-accuracy slider with slow update rate, and the Voyager’s smoothing would be appropriate.  But here the Continuum is trying to use the Midi CC data to generate fast transitional changes in the amplitude of a single note. This is an example of how Midi implementation in a synth has been optimized for one purpose, preventing from being used in the more esoteric way that something like the Continuum requires. This problem is not resolved using MPE; MPE does not indicate differences in controller precision and cc rates (see MPE+ page). Fortunately a sophisticated analog synth like the Voyager has both Midi and control voltage paths for controlling it’s sound parameters.