MIDI vs. CV/Gate: How Synths Talk to Other Gear

MIDI sends performance data as digital messages (notes, velocity, controllers, clock) and can handle many notes at once across 16 channels. CV/Gate drives analog circuits directly with voltages: one for pitch and one for when a note starts and ends, always for a single voice per pair of cables. Modern synths, DAWs and controllers speak MIDI, while Eurorack modules and many vintage analog synths speak CV/Gate. A converter, starting at roughly 175 to 230 USD for a full-featured one (as of Oct. 2026), bridges the two worlds.

MIDI and CV/Gate side by side

MIDI in detail

Connectors and data rate

The classic MIDI connector is the 5-pin DIN socket. Data runs serially at 31,250 baud, and each byte takes just under 0.3 milliseconds. A message consists of one status byte and at most two data bytes, so a note-on message occupies the line for about a millisecond. The specification limits cable length to roughly 15 meters (50 feet). A device sends from its Out, receives at its In, and the Thru socket passes the incoming signal on unchanged, which is how several synths are chained.

Many current devices have a USB port instead of, or in addition to, DIN. Most synths show up on a computer as a class-compliant device and need no special driver. One catch: a synth with a USB-B socket is built to talk to a computer. Two such devices cannot simply be joined with a USB cable. One would need host capability (a USB-A socket), or you need a box in between. Compact gear often uses 3.5 mm jacks for MIDI, and these come in two differently wired versions, Type A (the official standard) and Type B. If the types do not match, no signal arrives. An adapter that swaps tip and ring fixes it.

Channels, notes and controllers

MIDI has 16 channels. A device reacts only to messages on its own channel unless it is set to Omni (all channels). Channels are why several sound sources can be addressed separately over one cable. Notes are numbered 0 to 127, with 60 being middle C, and velocity has 128 steps too.

• Control Change (CC): knobs and wheels such as mod wheel, volume, sustain pedal or filter cutoff. Which number controls which parameter is partly up to each synth, so the controller chart in the manual tells you what is possible.
• Program Change: switches patches. Many devices organize patches in banks, which are selected with an extra Bank Select controller.
• Pitch bend and aftertouch: the bend wheel and pressure on held keys. Pitch bend has finer resolution than most controllers so the pitch glides without audible steps.
• System Exclusive (SysEx): manufacturer-specific messages, used for example to back up patch data or transmit parameters.

Clock and synchronization

Sequencers, arpeggiators and drum machines follow MIDI clock: the master sends 24 pulses per quarter note, plus Start, Stop and Continue messages and the Song Position Pointer, which says where in the song to play from. The clock is tempo-dependent, so a faster tempo means pulses closer together. There should be exactly one master, and all other devices follow as slaves. Two masters on the same network lead to fighting clocks, double starts or tempo jumps.

Older Roland gear uses DIN sync (Sync24, since 1980) instead of MIDI clock. It uses the same 5-pin socket, but electrically it is something entirely different and uses other pins, so an ordinary MIDI cable may not have all the necessary wires connected. Some Korg devices run at 48 pulses per quarter note. Both can be bridged to MIDI with suitable converters or master-clock devices.

MPE and MIDI 2.0

In ordinary MIDI, pitch bend and many controllers affect the whole channel, meaning all notes at once. With MPE (MIDI Polyphonic Expression, an official part of the specification since January 2018), each sounding note gets its own channel, so each finger can vary pitch, pressure and position independently. A master channel carries shared data such as program changes and pedals. Both sender and receiver must support MPE, and the voice count limits how many channels can be used.

MIDI 2.0 (introduced in 2020) extends MIDI 1.0 without replacing it. Devices use MIDI-CI to negotiate which capabilities both sides have, and gain higher resolution and per-note control. For everyday use, everything that works today keeps working. MIDI 2.0 should not be a deciding factor when buying a synth, since MIDI 1.0 still rules in practice.

CV/Gate in detail

Pitch CV: V/oct or Hz/V

With the widespread 1 volt per octave standard, voltage rises evenly: one volt equals one octave, so a semitone is about 83 millivolts. Most Roland, Moog, Sequential, Oberheim and ARP instruments and all of Eurorack use it. The second standard is hertz per volt, where voltage doubles with each octave. It appears on most, but not all, Korg and Yamaha synths. The difference matters: feed a V/oct voltage into a Hz/V input and the pitch no longer tracks, it sounds out of tune and the error grows across the keyboard. The manual or the technical data of the model says which curve it expects. Good converters offer both curves and an adjustable scale.

Gate, trigger and S-trig

The gate signal stays active as long as a key is held. The envelope starts when the voltage rises and moves into release when it falls. A trigger, by contrast, is a short pulse that kicks off an envelope or sequencer step without conveying how long the note is held. Drum modules and clock inputs usually work with triggers.

The switching types differ as well. With a V-trigger, the signal normally rests at 0 V and jumps to a fixed positive voltage to fire. The height varies by manufacturer, from about 2 to 10 V. With an S-trigger (short trigger), the signal rests high and is shorted to ground to fire. This type appeared on early Moog modular systems and is rare today. If the type does not match, the synth either never fires or never stops. Many converters let you set the gate type and level (for example 5, 10 or 15 V).

Levels in Eurorack

Eurorack uses common voltage ranges: audio up to 10 V peak to peak (minus 5 to plus 5 V), bipolar control voltages around 5 V peak to peak, unipolar 0 to 8 V, and gates, triggers and clocks 0 to 5 V. Connections use 3.5 mm mono cables, and power comes from a bus with plus and minus 12 V. When you cable modules to vintage gear, make sure the vintage unit's voltages (gate level, input range) fall within what the other side expects. If in doubt, check both manuals or ask a repair shop, because excessive voltage at an input can cause damage.

Converters and interfaces

MIDI to CV/Gate

A MIDI-to-CV converter receives MIDI notes and outputs pitch voltage and gate. Auxiliary outputs turn controllers, velocity or aftertouch into free voltages, for example for the filter. The voice count is the key detail: simple converters and modules are monophonic and serve exactly one voice. Polyphonic setups need several channels or a converter with several voice outputs. Two examples:

• Kenton Pro Solo Mk3: a standalone single-voice converter with V/oct and Hz/V (scaling adjustable from 0.92 to 1.62 V/oct), gate at 5, 10 or 15 V plus S-trig mode, three freely assignable auxiliary outputs, pitch bend up to 48 semitones, clock outputs and DIN sync (24 or 48 pulses). Price roughly 175 to 230 USD depending on the shop (as of Oct. 2026).
• Doepfer A-190-2: a simple Eurorack module with outputs for note (0 to 5 V over 5 octaves), pitch bend, velocity/volume and one selectable controller, with a 0/5 V gate. It handles one voice only and has no clock or start/stop output. Price roughly 107 to 140 USD (as of Oct. 2026).

DAW to CV

To output voltages straight from your DAW, you can use a DC-coupled audio interface. Such interfaces output not only audio but also steady voltages. With suitable software this becomes pitch, gate or modulation on several channels. It is flexible but costs more: a Eurorack interface with 8 DC outputs at ±10 V runs about 639 to 679 USD, excluding sales tax (as of Oct. 2026).

Sync converters and splitters

DIN sync, analog clock (pulses per step) and MIDI clock each have their own converters and master-clock devices. Some MIDI-to-CV converters output clock as well. If you control many devices, use a MIDI Thru box or an interface with multiple outputs instead of building long Thru chains.

Connecting to your DAW

The simplest route is USB: plug in the synth, enable the MIDI port in your DAW, done. Many synths also deliver audio over USB. For gear without USB you need a MIDI interface that converts the 5-pin connection to USB. A basic one-in, one-out USB MIDI interface costs roughly 40 to 50 USD (as of Oct. 2026). Make sure the synth is selected as the output of the MIDI track, that the channel matches, and that clock flows in one direction only. The sound itself goes to your audio interface separately, since MIDI carries no audio.

Hardware synths add an offset: the DAW sends the notes, the synth produces the sound slightly later, and the recorded audio lands a little late on the track. Many DAWs offer a per-track delay adjustment. If you record hardware, measure the offset once and compensate.

Latency, jitter and timing

MIDI is not imprecise, but it is not infinitely fast either. Over a DIN cable one note takes about a millisecond, and a ten-note chord spreads over roughly ten milliseconds. Jitter, the variation in delay, is in the microsecond range on DIN. USB is polled at fixed intervals, so delay averages about 0.5 milliseconds with somewhat more scatter. Measurements of older USB interfaces showed jitter up to nearly 2 milliseconds, and jitter generally becomes audible from around 5 milliseconds. In practice the difference between DIN and USB rarely matters. Larger timing problems usually come from software, such as audio buffers or an overloaded DAW. A tempo display that wobbles slightly (for example 119.6 to 120.4 BPM) is not a sign of drift, just normal noise in the clock pulses.

Tips for tight timing:

• Use a dedicated USB port rather than a hub and keep drivers current.
• Do not send too much data on one port: dense controller curves plus clock plus chords load a DIN line.
• Pick one clock master and set every other device to follow.
• Spread dense chords or fast controller sweeps across several ports or channels.

CV/Gate has no digital transmission delay and is therefore seen as very direct. Accuracy still depends on the converter, though: the quality of its digital-to-analog converter decides whether the pitch stays stable.

Retrofitting vintage gear

Analog synths from before MIDI (up to the early 1980s) often have only CV/Gate or no control input at all. There are three ways to bring them into a MIDI setup. Work inside the electronics belongs with a repair shop:

• External converter: the simplest and gentlest route for the instrument. The converter connects to the synth's CV and gate sockets (provided the unit has them) and needs the right curve (V/oct or Hz/V) and trigger type.
• Retrofit kit: for some models there are kits that add a MIDI socket inside the instrument. The work belongs in a repair shop. Cost depends on model and effort: varies by shop, get a quote.
• Modern reissue: some classics are available as new versions with MIDI and USB.

When buying a used unit, look at the back panel: which sockets are there, are they undamaged, do the levels fit? More checkpoints are in Buying a used synthesizer: what to check. Why a converter often serves only one voice is covered in Monophonic vs. polyphonic.

Costs at a glance

Common mistakes

• Channel mismatch: sender and receiver are set to different MIDI channels and the synth stays silent.
• Out and Thru mixed up: Thru carries only the incoming signal, not what the device plays itself.
• Several clock masters: two devices send clock and the tempo jumps.
• MIDI loops: a device echoes received notes back (check Local Control and the DAW's soft thru), so notes double or hang.
• Hz/V instead of V/oct: pitch runs out of tune across the keyboard because the wrong curve is set on the converter.
• Wrong trigger type or level: the synth does not fire or does not stop. Set gate level and V-trig or S-trig to match.
• TRS Type A and B mixed: no signal arrives. A crossover adapter or a setting on the device helps.
• DIN sync cable mistaken for a MIDI cable: same socket, different wiring.
• Stuck notes: a note-off gets lost, for example through a wobbly cable or overload. The panic function of the DAW or synth ends all notes.
• Drifting pitch after power-up: many analog synths need warm-up time. Only then match tuning and converter scaling.

Decision guide

• Modern synth with a DAW: USB MIDI is enough, plus a 5-pin cable for hardware sequencers.
• Several hardware devices together: 5-pin MIDI with one clearly defined clock master and clean channel assignment.
• Vintage analog synth with CV/Gate: external MIDI-to-CV converter with the right curve and trigger type.
• Vintage synth without CV sockets: retrofit kit at a repair shop, or a different instrument.
• Eurorack system: MIDI-to-CV module (multi-voice if needed), or a DC-coupled audio interface for DAW control.
• Expressive playing with per-note control: check that the devices support MPE.

For how sound generation and hardware fit together, see Polyphony, oscillators and filters. For how analog, digital and virtual analog synths differ, see Analog vs. digital vs. virtual analog.