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Sequential Tom

Programmable digital drum machine

Following the Drumtraks in vocation and the MAX in appearance comes TOM, Sequential’s latest. Simon Trask finds out if reverse drum samples really do have a use.

Not content with producing the world's first tunable drum machine in the Drumtraks, Sequential have built another load of new goodies into its younger, cheaper brother.

It's now over a year since Sequential's first foray into the digital drum machine world produced the Drumtraks, the world's first tunable drum machine. That machine's original asking price of £950 was pretty much par for the course at the time, but the more recent offerings from Roland and Yamaha have changed people's expectations of how much a high-quality digital drum machine should cost. Yamaha's RX11 even offers tuning facilities, albeit with preset levels rather than the continuous variation present on the Drumtraks.

So with Sequential's earlier offering currently looking a bit long in the tooth (though still an excellent machine), a new drum product from the company has been on the cards for a while. And a few months back, that machine turned out to be the TOM, a programmable machine that combines many of the features that made the Drumtraks such a winner, with a price-tag that's significantly lower.


The visual side of the TOM has obviously been designed to match Sequential's MAX and MultiTrak polysynths, which means it has a very smart, clean-cut and contemporary appearance. What it also means is that the casing is a bit on the light side, though such considerations don't seem to have harmed Roland's TR707, a flimsy machine if ever there was one.

The TOM has eight sounds onboard and can provide access to a further seven via a plug-in cartridge. Internal sounds consist of bass drum, snare drum, two toms, open and closed hi-hats, crash cymbal and claps, each sound being allocated its own triggering pad. There's storage space for 100 patterns and 100 songs, and standard (non-expanded) memory holds 2300 notes.

As drum machine pads go, the TOM's have a usefully firm response. But this is more than can be said for its non-instrument pads, which is unfortunate as they probably get as much of a thrashing in the long term.

Operation of the TOM is divided into three modes: Pattern, Song and Control. In the tradition of Sequential's front panels, layout is clear and informative; the TOM adopts the sort of matrix display format previously used to present the MultiTrak's voice parameters, and combines it with the complete listing of functions that was adopted on the SixTrak. The result is a layout that gives easy, rapid access to every function, so all credit to Sequential on this one.

All of TOM's functions are listed in three columns - one column for each of the modes mentioned earlier. Each column is headed by its own selector button and LED, whilst down the left-hand column are LEDs for each function in the columns. Parameter values appear automatically in a four-character, seven-segment display to the right of the function list, where they can be modified using a standard numeric keypad.

A neat feature is the way a number of functions can readily be accessed and altered during recording. These include metronome adjustment and switching, error correction, and instrument erasure together with Improv, Stack and Reframe record modes (all of these from the Pattern list), and instrument tuning, volume, pan and auto-repeat from the Control list. This gives you flexible control over both medium and material, which can only be a good thing.

Sequential have a knack of making the centralised digital access approach to programming work for them, and the TOM is no exception.


The TOM's sound-generating circuitry is only capable of generating four sounds at any one time. This is an unusual and irritating limitation that'll be more apparent if you decide to avail yourself of the TOM's cartridge sounds. If you're into building up layers of latin percussion on top of the standard kit sounds, you might have one or four problems.

Fortunately, the effect of this limitation is lessened by the TOM's ability, when all four channels are occupied, to assign a new instrument event to whichever channel has less remaining sound to generate. The arrangement is still a nuisance, though.

In the normal run of things, each drum voice is assigned to one channel, so if it's played again before the first sound has run its course, the sound is automatically retriggered. Stack mode, however, lets you reassign a sound to a different channel if that sound is already active. Quite a nice feature, though it quickly limits the number of different instruments that you can play at once.

A definite plus-point for the TOM - as it was on the Drumtraks - is its instrument tuning facility. A wide tuning range (32 levels) is available, and any instrument played/recorded assumes the current tuning value as applied to its own range. Tuning is thus note-specific as well as drum-specific, and it's possible to create a variety of disparately tuned sequences by adding a new note or notes each time round the Record loop.

You can vary tuning in real time during recording, and this allows not only the obvious tom rolls, but also a whole load of much more exotic - and more contemporary - effects. The TOM's demo patterns show these off rather well.

"TOM puts a stop to tedious chip-swapping by allowing you to plug in a ROM cartridge containing seven extra sounds."

Instrument volume and instrument panning are also note-specific, and can also be varied during recording, and you probably don't need me to tell you that putting all these effects together can produce some startling percussive results.

As if this wasn't enough, the TOM also provides a Reverse facility (a first in the sub-£1000 drum machine world) instigated at the press of a button. It's certainly quite a novelty, hearing drum samples played backwards in this way, and better still, reversing is also a storable parameter. The only problem is that Sequential have omitted to give the Reverse function an LED to tell you it's activated, so it's all too easy to end up with a reversed cymbal thwack just at the point you wanted a conventional crash. The perils of experimentation...

Of course, all these weird and wonderful voice-changing facilities wouldn't be much use if the voices were no good in the first place. Overall, the TOM's samples don't quite have the clarity and sparkle of their Japanese counterparts, but they possess a dryness that might well be appealing in its own right. And if you don't like the dryness, you can always use signal-processing to help relieve it.

If you work at it, you can get some sharp, well defined cymbal and hi-hat sounds and some colourful toms, though the bass drum seems to lack that last bit of 'oomph', no matter what you do with it.


Separate global controls are provided for volume, tempo up/down, start/stop, function select, and Reverse and Cartridge select.

You begin programming on the TOM by accessing the Pattern section. This has a number of novel programming features in addition to simply opening up the machine's memory for real-time writing. For instance, a facility called Improv lets you record instruments as 'improvised' events that only occur on a selectable percentage of loops within a pattern - a very welcome surprise element, this. The same can be said for the already-mentioned Stack mode, and the Reframe facility, which lets you redefine the start-point of a pattern after it's been recorded - great for indecisive programmers.

Real-time programming is really the TOM's forte, but the Pattern section also includes a function called Single Step. The idea behind this is to provide a means of inserting and deleting voices, beat by beat, from an already-recorded pattern, but if you start off with nothing recorded at all (or delete all the voices in that pattern to give you a blank piece of paper, as it were), there's no reason why you shouldn't be able to use Single Step as a means of programming in step time.

Once you've finished with recording patterns, you turn to the TOM's Song section. But aside from the pattern-chaining function that is its raison d'etre, Song mode has a number of interesting organisational features. For a start, 'subsongs' may be included as a link in the chain. These are other songs that can be called up in the course of the current song, after which the next link in the chain is accessed. You can also set sequences of patterns to loop a number of times within a song chain, which can jave a lot of programming time.

But most interesting of all in the Song section is the Human Factor facility. In essence, this lets you program a percentage of time that a song plays recorded instruments at slightly different tunings and levels from the ones already programmed for them. There isn't space to go into details here, but this sort of feature can make all the difference between a drum machine sounding like a box of moronic technology and the same unit appearing to be a much more versatile, musical instrument.

Full marks to Sequential, then, for applying a bit of imagination to their programming facilities - and making them easy to use.

Rear Panel

This houses sockets for left/phones and right/mono audio outs (phones receive a stereo signal), MIDI Out and In, clock out, tape out, clock/tape in, trigger out and programmable footswitch. Conspicuous by their absence are individual audio outs for each of the TOM's drum voices - and that's a real disappointment.

You can store patterns and songs over MIDI, but Sequential have sensibly provided a tape save/load option as well. All memory is saved in one go (so you can't choose between patterns and songs), and a complete 2300-note save takes about three minutes.

Trigger Out provides a 5V, 10msec pulse that can be used to trigger and step through non-MIDI sequencers (Sequential give the example of their own Pro One), and you can play/record these pulses by selecting Cartridge and tapping the eighth instrument pad.

"Full marks to Sequential for applying a bit of imagination to their programming facilities - and making them easy to use."

Clock signals are output automatically when a song or pattern is running, and the power-up default clock rate is 24ppqn. Other possible settings are 0.5, 1, 1.5, 2, 3, 4, 6, 8 and 12ppqn, which is most odd, and would seem to imply that Sequential intend the TOM to act as a master device to trigger a sequencer, rather than another drum machine. For clock in, the TOM can adjust to 24, 48 and 96 ppqn, which is a lot more sensible.

The really good news is that the TOM can sync to and from tape via its tape out and clock/tape in sockets.


The TOM operates in the same three MIDI modes as the MultiTrak, which should make for a good pairing. Sequential have implemented keyboard control of all the drum sounds via MIDI - and this includes the cartridge sounds, with internal and cartridge sounds being accessible at the same time. Instrument pan (left/centre/right) and trigger out facilities are also allocated to selected keys, whilst 32 adjacent keys are allocated to the 32 tuning levels. If your MIDI keyboard is velocity-sensitive, the TOM will receive these values from the instrument keys and assign them to its own volume levels. So it's not difficult to see that by pressing a tuning key and a panning key together with an instrument key or instrument keys on a dynamic keyboard, programming the TOM becomes an extremely easy task. It's even possible to control instrument tuning by use of the synth's pitchbend wheel - logical, but not the sort of thing you can use lightly.

All this works the other way, of course, so that you can use the TOM's programming pads to play notes from a MIDI keyboard, and use its programming facilities to record sequences.

On the MIDI synchronising front, the TOM transmits MIDI timing bytes and MIDI start/stop/continue codes for linkup with a sequencer or even another drum machine.


A strong feature of American drum machines in general is the way their designers give musicians the means to add drum voices without unnecessary duplication of hardware. Unfortunately, this has traditionally required users to open up their drum machines and swap chips each time they wanted some new sounds.

Thankfully the TOM puts a stop to this tedious process by allowing you to plug in a ROM cartridge containing seven sounds, giving a total of 15 simultaneously-available drum voices. Four such cartridges will be available by the time you read this review (though sadly not in time to actually be reviewed), with a sizeable RRP of £119 each - though when you consider that individual plug-in drum chips generally cost around the £30-40 mark, the price doesn't seem so bad.

Each cartridge gives you a different family of sounds: Standard Drumkit, Latin Percussion, Electronic, and Effects.

The first of these cartridges includes ride cymbal, cymbal bell, cowbell and rimshot; Latin Percussion includes conga slap, timbale, timbale rim, agogo bell and guiro; Electronic sounds include kick drum, tom, laser one and record scratch (!); and Effects include dog bark, car horn, orchestra 'tutt' and crowd. A few lemons, then, but a commendably wide range of voices to be going on with - and there may be more to follow.

Internal and cartridge sounds can all play at the same time - the only limitation is a physical one (the TOM only has eight programming pads, remember) at the recording stage. Another point to bear in mind, though, is that the limit of four voices playing at any given moment still applies, as this is a limitation of internal system design.

Anyway, equally commendable is the way Sequential have made room for future TOM memory expansion. Three IC sockets on the machine's PCB are reserved for plugging in three 8K RAMs, each of which gives another 2700 notes' worth of storage space. These RAMs can be bought for £39 each, and you can either fit them yourself or get your friendly local music shop to do it for you. A full complement (together with the inbuilt RAM) will give you a capacity somewhere in the region of 10,000 notes, which can't be bad.


Few hi-tech musical instruments escape a pros-and-cons specification that presents the musician with a purchasing dilemma. The TOM is no exception. In fact, it presents a number of intriguing dilemmas, and in the final analysis, personal needs and wants will dictate the degree of its eventual success in the marketplace.

On the con side, there are quite a few aggravating minus-points that really detract from the machine's appeal. Like the lack of individual voice outputs, the four-at-once voice placement limitation, the lack of a really extensive step-time recording section, and a relatively high (though not exorbitant) price that betrays the higher manufacturing costs US hi-tech companies have to face by comparison with their Japanese and Italian competitors.

But the plus points are also significant, and plentiful. The built-in upgradability of the machine's voicing and memory spec is probably the biggest boon, but there's also the flexibility of the TOM's voice-controlling and programming sections to consider, too. For comparative newcomers to the field, Sequential have sure given their latest drum machine some design thought - and it's paid off. Credit is also due to them for attempting to get as much mileage out of MIDI as is possible in a drum machine context, whilst a healthy range of triggering and synchronising options should make TOM a flexible centrepiece of a combined MIDI and non-MIDI setup.

But the biggest dilemma of all is the one facing the reviewer. How do I end this review without coming to a wishy-washy, indecisive conclusion? I can't. Take the TOM for a spin, try out as many of its features as you can, and come to your own conclusions. I'm going to a special clinic for people who keep wishing drum machines had everything.

RRP of the TOM is £795 including VAT.

Further information from: Sequential Europe, (Contact Details).

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Microskill AS32

Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Jul 1985

Gear in this article:

Drum Machine > Sequential Circuits > Tom

Gear Tags:

Digital Drums

Review by Simon Trask

Previous article in this issue:

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