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Sync Outside The Box

Keeping Synths & Grooveboxes In Time By Chris Korff
Published January 2023

Sync Outside The Box

Going DAWless presents many challenges — not least keeping all your gear in sync...

Desktop noise‑makers have never been cheaper: for almost literal pocket money, a music production novice can pick up a drum machine, a sampler or a groovebox and start making a racket. It rarely stops there though: that first bit of kit can end up being a gateway purchase, with the next week’s paper‑round money already spent on a new device before the first has been mastered.

Other than the ‘running before you can walk’ phenomenon, this can lead to another problem: how to get those two devices to play in time. Unlike with DAWs and USB peripherals, keeping separate hardware boxes in sync with each other without a computer is far from an automatic process. In this article, I’ll explain the various ways in which synths, sequencers and grooveboxes can be kept in step, using a few common machines as examples.

Keeping your gear in sync can occasionally be very straightforward, and occasionally less so, depending on what gear you’re using and what your requirements are.

Jacking Up

I’ll start simple, with the ‘sync’ socket that many affordable synths, drum machines and the like are now fitted with. There’s no magic to it: sync is a simple analogue pulse (around +5V) that plays in time with whatever device it’s coming from, to tell the next device in the chain when to play its next notes. Fundamentally, it’s a metronome, and its blips are passed using a jack cable (usually a mono mini‑jack).

Modern Korg gear is easy to synchronise: just connect the sync out jacks to the sync ins, and your devices will maintain the same tempo.Modern Korg gear is easy to synchronise: just connect the sync out jacks to the sync ins, and your devices will maintain the same tempo.Here’s a nice easy example. I’ve hooked up a Korg Volca Kick’s sync out jack to the sync input on a Korg Monologue. Now, if I hit Play on both devices at the same time, they will both play at whatever tempo I set the Volca to. Easy! Even better, their synchronisation is an ongoing process, so if I tweak the tempo on the Volca Kick, the Monologue will follow suit. And because both devices have both a sync input and output, I can swap them around so that the Monologue determines the tempo rather than the Volca, if that’s more convenient.

At this point, I should mention that one of the reasons this works so seamlessly is because they are both Korg devices, and as such they use the same sync ‘ppqn’ standard — for more info, see the ‘On The Pulse’ box.

Now, this is about as basic as synchronised setups get, and it has its limitations. For one, you have to press Play on both devices simultaneously, because the sync pulse on these Korg devices is pervasive; it begins the moment you turn them on, it doesn’t start and stop when the sequencer does, and there’s no additional signal telling downstream devices when to do so. Some devices, like Behriner’s RD‑series drum machines, and Arturia’s MicroFreak, MiniFreak and BeatStep Pro, can make use of a TRS cable to send start and stop messages to other kit alongsidse the sync pulse, but the usefulness of that depends on whether your other kit will heed those messages. And, in any case, if you accidentally hit Stop on your slave device, the master will continue playing — and to get them back in time again you’ll need to carefully time your next hit of the slave device’s Play button, otherwise the two will be offset.

This kind of transport‑control jockeying will be familiar to anyone who’s ever DJ’ed, and the skill of it (and occasional happy accidents when you get it wrong) can be a fun part of the DAWless experience — but if your sync’ing needs are more complex, and especially if you have a sequencer or workstation with a proper ‘song mode’, you’ll need to turn to...

MIDI Clock

MIDI is good for more than just shuffling notes about. Part of its specification includes something called MIDI Clock, which works much like sync but can also include other messages, such as transport control and Song Position Pointer (SPP) data. It can be used alongside other MIDI messages to convey things like time signature. The transport messages (where present) include start, stop, continue, rewind and fast‑forward commands, while SPP tells devices not only what tempo to play at, but where in the sequence or song to play from. Note, though, that not all MIDI devices pay attention to the extra data: simpler devices, such as monosynths with no more sequencing ability than a basic arpeggiator, may simply use MIDI Clock in much the same way as a sync signal.

Robin Vincent’s recent article about setting up MIDI (SOS November 2022) covered the fundamentals of MIDI connections and MIDI Clock, and is well worth a read if you need a recap. I won’t add much then, except to say that sync pulses and MIDI Clock can happily be used at the same time: I can slave my Monologue to a DAW, or a hardware workstation like an MPC, using MIDI Clock, and then send its sync pulse out to a Volca, and everything will play in time.


Sync and MIDI Clock are the two most common ways of keeping the new generation of standalone grooveboxes and synths locked together, but what of the murky world of modular? Anyone who has thrown themselves down the Eurorack rabbit hole will probably already be familiar with the various sync’ing solutions, but if you’re growing a DAWless setup and wondering whether a modular system could slot into it, the general gist is this: any module that can be synchronised with other modules or external gear — a sequencer or arpeggiator, say, or a tempo‑based delay module — will have a ‘clock in’ socket (and often a ‘clock out’ too). These ‘clock’ signals are very similar to the syncs found on the Volcas, Boutiques, BeatSteps and TR‑style drum machines of this world, in that they are both regular analogue pulses. Indeed, these two ‘standards’ (such as they are) are interoperable; you can often slave a modular sequencer to a drum machine’s sync signal, or vice versa, quite happily... with a caveat.

Modular gear can also join the sync party — provided you send it the right signals...Modular gear can also join the sync party — provided you send it the right signals...

The chief difference between sync and modular clock is that the latter is essentially a ‘play the next note now’ message, whereas sync signals usually have several blips (‘pulses’) per quarter note. To illustrate, let’s say you’ve connected the sync out from a Korg Volca (which runs at 2ppqn) to the clock input on a sequencer module. Assuming you’ve programmed the sequencer to play quarter notes, it will essentially run at double‑time, because it’s receiving two ‘play next note’ messages for every quarter note that the Volca plays. This can be worked around easily enough — by spacing out your Volca notes, say, or treating the sequencer notes as quavers rather than crotchets — but if the device generating your sync signal runs at 28 or even 48 ppqn then your sequencer will be in machine‑gun territory, and unless you’re exclusively into gabber then that probably won’t be very helpful.

In that case, you’ll need what’s known as a ‘clock divider/multiplier’ module, which does exactly what its name describes: it takes an incoming clock signal, and then divides or multiplies it so that, for example, a 4ppqn clock becomes a 2ppqn one (ie. it’s divided by two) or an 8ppqn clock (multiplied by two). Such modules are available individually, but some Eurorack sequencers, like the Eventide Misha, have clock divider/multipliers built in, allowing them to conform to a wide range of standards — as well as letting you get creative with half/double‑time sequencing.

Modular sequencers may also include inputs for Trigger and Reset signals. The former is much the same as the ‘start’ messages that you get from TRS sync jacks (indeed you can use those signals with modular, using a correctly wired Y‑cable), while the latter simply starts the sequence at the beginning — useful if you’ve got yourself out of step with another sequencer, or you want to play with polyrhythms.

A final word on modular sync’ing: clocks, like sync signals, are nothing more than regular analogue pulses — which are precisely what you get out of a square‑wave LFO. So, it’s perfectly possible to use one of your modular synth’s LFOs as a clock source, with the LFO rate essentially functioning as a tempo control. Conversely, you can also use the clock signal itself in other parts of your modular, to trigger envelopes and such.

I Sync, Therefore I Am

Retrokits make a range of hubs and converters that can get your gear playing in time, whichever sync standard it uses.Retrokits make a range of hubs and converters that can get your gear playing in time, whichever sync standard it uses.So, keeping your gear in sync can occasionally be very straightforward, and occasionally less so, depending on what gear you’re using and what your requirements are. If you find yourself trying to sync to pieces that are ‘incompatible’, though, worry not: you’re far from the first person to experience this problem, and there are various gizmos around that can help. Special mention should go to Retrokits, whose RK‑006 hub can help keep your USB, MIDI, sync and modular gear all running in time.

Before the days of DAWs and USB connections, knowing how to synchronise your gear was the foundation of setting up an electronic music studio. Indeed, it was rather more complicated back then, with analogue synth manufacturers employing their own standards for sync signals, and MIDI still in its infancy. And if you wanted to record audio alongside your synths and drum machines, you had to dabble in the arcane art of SMPTE sync, sacrificing one of your tape channels for timecode so that your MIDI sequences and tape recordings stayed in time.

So, no, setting up a studio without a computer isn’t easy, and never has been. But if you wanted an easy life you’d just use a DAW... Wouldn’t you?  

On The Pulse: PPQN

Older readers will probably be familiar with the term ‘ppqn’, which stands for pulses per quarter note. In the days before MIDI, different manufacturers had their own ideas about how best to synchronise things, and one of the primary differences between them was the ‘resolution’ of their sync signals. As the world adopted MIDI Clock as the de facto standard, the specifics of who was using what ppqn stopped mattering, but with new analogue instruments being released almost daily it’s back in the spotlight.

An instrument’s ppqn defines how many pulses there are for each crotchet it plays. So if you’ve got a drum machine playing and it outputs sync at 4ppqn, there’ll be four pulses for each quarter note (crotchet), or 16 pulses in a 4/4 bar. If the device you’re sending your drum machine’s sync to is also running at 4ppqn, then everything will work as it should. However, if it runs at, say, 2ppqn (which seems to be the standard that Korg have adopted since the Volca series), then it will only play one crotchet for every two that your 4ppqn drum machine does.


Sometimes it isn’t necessary to keep two devices in time per se, merely to get one device’s sequencer to trigger notes on another. In MIDI‑land you do this by assigning corresponding MIDI channels and note numbers to both devices, but in the analogue world it’s done using the aptly named trigger inputs and outputs. To take the Behringer RD‑8 as an example, it’s possible to use the sequencer lanes dedicated to the accent, hand‑clap and cowbell to trigger external gear — for example a snare module in your Eurorack setup, or any other synth that has a trigger input. Indeed, trigger, gate and clock signals are somewhat interchangeable, depending on what you’re doing. Be aware, though, that there are different standards for trigger voltages among different manufacturers: you may need to boost a trigger using an amp module in order to get the receiving device to register it.