Or how to get the best from your electronic instruments by syncing them together. Part three looks at drum machines and sequencers.

Even if your synthesiser set-up is astonishingly basic, you must at some time or other have contemplated adding a sequencer. And what a good idea it is. Suzanne Cianni, American synthesist extraordinaire, feels the sequencer to be as important a piece of electronic music hardware as the filter or the voltage-controlled oscillator: I tend to agree with her. They are not, as many would have you believe, something to make up for deficiencies in playing technique. Instead they allow control over a synthesiser that would otherwise be impossible.

The sequencer's metronomic precision has a 'feel' all its own and whilst some may argue that this is cold and clinical, it remains a fact that some of the most technically-proficient synth and keyboard players employ sequencers and microcomposers in their music. And sequencers also allow someone who would otherwise be unable to realise his or her musical ideas to do so quite impressively, though having said that, owning a sequencer won't make your music a whole lot better overnight - if it's dull and boring it will remain dull and boring, sequencer or no sequencer. So, with reservations, sequencers are wonderful. The only real problems are the age-old ones of interfacing and synchronisation. Those of you who read last month's enthralling instalment will no doubt recall that while many synths operate under a standard control voltage law of one volt per octave, gate and trigger inputs and outputs don't always match up so readily.

Now, synths that feature one method of triggering cannot normally be used with sequencers employing a different method without a suitable interface, circuits for which were published last month. The other way round this problem is to use only compatible equipment, but this isn't always feasible, as you may wish to use the facilities provided by a sequencer not entirely compatible with your synth. Construction of these interfaces should present few if any difficulties and only costs a few quid, so the problem is not as serious as it seems.

Drum Machine

Having successfully connected sequencer to synthesiser, you now have the problem of interfacing sequencer to drum machine. Again, this procedure can be fraught with problems in the wake of manufacturers fitting their own interfacing systems.

Figures 1 and 2 show the internal layout of a typical sequencer and a typical drum machine respectively. They operate in a similar way in that the memory sections or both of them are stepped through by a clock of some form. It therefore follows that if you replace the clock in the sequencer, with the clock from the drum machine, you can control both units simultaneously and in perfect synchronisation. Well, that's the theory anyway!

If the drum machine's output isn't the same as the sequencer's, things may go drastically wrong. Let me explain...

In the good old days, when Cardiff City were in the First Division and things were a lot simpler than they are now, sequencers needed only one pulse to step through one note. And to oblige, drum machines used to output one pulse for each beat. Then one day Roland, in their infinite wisdom, decided that in order to improve the resolution of real-time sequencer programming they would use a system of 24 pulses for every note, and to this end devised their now famous five-pin DIN Sync socket. The pins carried the 24 pulses-per-beat clock output and a special start/stop pulse, effectively prohibiting any marriage between Sync-equipped hardware and earlier machines. Of course, it was a jolly good wheeze on Roland's part because people were more or less forced to buy their sequencers and microcomposers. In an attempt to follow suit, many drum machine manufacturers started incorporating this system into their products but, astonishing though it may seem, they couldn't even get that right and so we now have drum machines that output a variety of different clock time-bases:

24 pulses-per-beat - Roland, Hammond, Korg, E-mu Systems
48 pulses-per-beat - Linn
96 pulses-per-beat - Oberheim
Variable - Yamaha, Sequential Circuits

What this means in practice is that if you try to connect a Roland MC202 to a Linn it will run at twice its speed, while an Oberheim run off a Linn will run at half its speed. You follow?

To overcome this, you could try programming your sequencer at half or twice the normal speed (depending on the situation you find yourself in), though on purely musical grounds this isn't an altogether satisfactory solution.

An alternative is to invest in one of the several sync converters currently available (previous instalments in this series have already been through these, so I won't bore you by listing them all again), but seeing as some of these cost about the same as a decent programmable drum machine anyway, you've got to be pretty serious about your syncing before you invest in one.

Still, the advent of MIDI is a concrete indication that manufacturers are now willing to co-operate to some degree on this matter: in the meantime, things will just have to remain a little bit complicated. In an attempt to ease this complication, I've drawn up a table that sets out the sort of link-ups that can be achieved (albeit with a fair bit of customisation in many cases) and a list of 'commandments' which, if strictly adhered to, should make drum machine and sequencer syncing a lot less painful.

TRIGGER OUTPUTS

TRIGGER INPUTS

ROLAND

ARP

MOOG

OBERHEIM

YAMAHA

LINN

EMU

HAMMOND

SCI

BOSS

KORG

ROLAND

S,M,C,PT

C,PT

C,PT(I)

X

M,S

PT

S

S

M,PT,C

PT,C

S,PT,C(I)

ARP

PT,C

PT,C

PT,C(I)

X

X

PT

X

X

PT,C

PT,C

PT,C(I)

MOOG

PT,C(I)

PT,C(I)

PT,C

X

X

PT(I)

X

X

PT,C(I)

PT,C(I)

PT,C(I)

OBERHEIM

X

PT

PT(I)

S,PT

S

X

X

X

PT,S

PT

PT(I)

YAMAHA

S,M

X

X

X

S,M

X

X

X

S

M

X

LINN

PT

PT

PT(I)

X

S

S

X

X

PT,S

PT

PT(I)

EMU

S,PT

PT

PI(1)

X

S

X

S

S

PT,S

PT

PT(I),S

HAMMOND

S

X

X

X

S

X

S

S

S

X

S

SCI

S,M

X

X

X

S,M

X

S

S

S,M

X

S

BOSS

PT.C

PT,C

PT,C(I)

X

X

X

X

X

PT,C

PT,C

PT,C(I)

KORG

S,PT,C(I)

PT,C(I)

PT.C(I)

X

S

X

S

S

S,PT,C(I)

PT,C(I)

PT,C,S