The explosion of acid house records made Roland's TB303 Bassline the most hip technology of the year - but what makes it the acid bass machine?

AMONG THE STEADY parade of hi-tech musical instruments that has appeared over the years, relatively few have become classics. Roland's monophonic, analogue TB303 Bassline has never previously been what you'd call a classic machine, yet during the past year it has seen a surprising renaissance as "the acid machine". Why? Simply because it was used on the seminal acid record - Phuture's 'Acid Tracks' (on Chicago's Trax Records which appeared on UK import back in November '87), which, arguably, gave the whole style its name.

According to Marshall Jefferson, who produced and mixed 'Acid Tracks', the track came about by accident. Speaking in The Face (December '88) he said: "When you get an acid machine you don't pre-program anything. You just hit some notes in a machine. DJ Pierre, he was over and he was just messing with this thing and he came up with that pattern."

"That pattern" is a syncopated five-note riff repeated (with occasional variations) on the 303 over a house beat for 11 minutes and 17 seconds. Minimalist indeed, and a refreshing change at a time when house music was getting bogged down in its own cliches. And with the 303 pushed to the forefront, it's hardly surprising that other musicians wanted to know about the instrument which was making all these strange sounds - and get hold of one for themselves. A formula was in the air.

Ironically, the 303 by itself isn't able to make all the sounds attributed to it in 'Acid Tracks'. It's actually being passed through some form of external filtering (perhaps through a synth with an audio input and a more powerful filter) to achieve the sort of effects found on 'Acid Tracks', as the 303's own filter resonance is, to put it politely, weak. Yet although resonance is such an important aspect of the track, it hasn't been picked up on as a feature by the subsequent flood of acid records.

On the TB303 you can adjust filter cutoff frequency, resonance, envelope modulation and decay parameters in real time from dedicated front-panel knobs (in the true fashion of old analogue synths) all at the same time - if you can find enough fingers. This is precisely what Marshall Jefferson and DJ Pierre did on 'Acid Tracks', thus (re)introducing the idea of timbral modulation as a significant (indeed, prominent) musical feature. Much of the interest in 'Acid Tracks' springs from its syncopated cross-rhythm within the bass riff, which tugs against the 4/4 beat with varying strength depending on the timbral changes and associated degree of rhythmic reinforcement from the "external" resonance. I can't help feeling this is something not many people picked up on in the subsequent rush to cash in on the acid - and TB303 - craze. In fact, the possibilities thrown up by 'Acid Tracks' have for the most part been sadly under-explored. As house producer Bam Bam (Chris Westbrook) has said: "It's one thing having a 303, it's another thing knowing how to use it."

SO THIS SMALL, lightweight silver-grey box with knobs on, which many original owners had probably either sold or forgotten about, became a desirable instrument once again - on the strength of one record. And with it the Bassline's second-hand value began to increase.

In more ways than one, the TB303 is a rarity: a dedicated bassline machine with onboard sequencing, it was originally introduced by Roland as a companion to their TR606 drum machine (a modest unit by today's standards which has seen no equivalent revival).

The 303's synthesis section is limited compared to that of Roland's MC202 microcomposer (another currently in-vogue analogue unit). In addition to the four controls mentioned earlier, you can select square or sawtooth waveforms, and program accents and slides into patterns. This relative simplicity provides an interesting balance of variety and consistency in the 303's range of sounds (changing not only the timbre but the envelope) makes it easy to use and somehow well-suited to the sort of use it gets in 'Acid Tracks'.

The 303's sequencing facilities are much more sophisticated than those of the MC202, and unlike the latter machine its sequences are battery-backed during power-down. In fact, the 303 can be run off batteries or a 9V DC power supply, which means that, with a pair of headphones, you can use it anywhere. Weighing just over 2lbs and measuring 11.5" X 5.5" X 2.5", the 303 must qualify as one of the most portable hi-tech musical instruments ever made.

It's easy to see how basslines can be entered "by accident" into the 303. Pitches and durations have to be programmed separately, and you need a clear head if you're going to end up with what you intended. Pitches are entered using a one-octave "keyboard" on the 303 itself (actually a series of buttons in keyboard layout). The keyboard's range can be expanded to three octaves using octave up/down buttons, and accents and slides can be programmed for individual notes using dedicated buttons (while an accent knob allows you to adjust the level of accent in real time during playback). Durations can either be programmed in step time or tapped in in real time; in practice, tap entry can give less reliable results than step-time entry.

The 303 can store 64 one-bar patterns and seven tracks. These tracks are in fact independent songs, each of which can have up to 64 steps (a step consists of a pattern, transposed if required). Patterns are organised as four groups of 2X8 patterns, and called up by pressing the eight "white note" buttons on the 303's keyboard (with A and B buttons switching between two sets of eight patterns per group). Each track can draw on a maximum of 16 patterns, rather than the full 64 patterns.

The 303 allows you to select either a 16th note or a triplet 8th note as the basic step unit; for longer notes, you press a tie button (so a crotchet equals four tied 16ths, for example). You can select any pattern length up to 16 16th notes or 12 triplet 8ths. If you want a longer riff you can spread it across two or more patterns and use the 303's ability to link together any consecutive combination of patterns 1-4 or patterns 5-8 (so 4/4 plus 5/8 would give you a composite 13/8 pattern). However, you have to record the patterns individually. Alternatively you can use pattern-linking as a means of looping up to four different patterns without having to chain them together in a track.

Patterns can easily be transposed in Play mode, within the keyboard's one-octave range, by pressing the Pitch button and the required new root pitch. Additionally the 303 can be tuned down a minor seventh or up a major sixth in fine increments courtesy of its global tuning knob.

With its choice of two time-bases and a wide variety of time signatures, the 303 offers plenty of enticing rhythmic possibilities for the experimental musician, whether it's synced up to a drum machine or to another 303 (hey presto, you've got counterpoint). Yet just because an instrument has a certain complement of features, do they all have to be used? I don't think I've heard any acid (or any other) record which has fully exploited the 303. The answer, of course, is no. Ideas are more important than features, but perhaps for some people there's a closer relationship between the two than there is for others.

How many ideas should a piece of music contain anyway? When is minimalism a virtue and when is it a sin? And what is a finished track nowadays? With remixing an established fact of musical life, it seems there's no such thing - only endless permutations of the basic material. When a certain record company supposedly released a track produced by Todd Terry before he'd finished working on it, how many people knew or cared? It was out on record, so it was complete.

But hang on a minute. I think I was talking about a monophonic bass synth. The only method of syncing the TB303 to the outside world is via its DIN Sync input, which means you can easily sync it to, say, Roland's TR808 drum machine, but if you want to bring it into the world of MIDI you need a sync converter box such as Roland's SBX10 or Korg's KMS30. Roland gave the 303 CV and Gate outputs, but unfortunately no equivalent inputs (in contrast, they fortuitously included CV/Gate inputs on the MC202, allowing it to be slaved off a MIDI sequencer via a MIDI-to-CV converter). The only other sockets on the 303's rear panel are an audio output, a headphone output, and an audio mix input (allowing another instruments' output to be routed through the 303).

FOR MANY PEOPLE nowadays the 303 signifies acid music, yet it doesn't have to be the only acid machine. To quote Marshall Jefferson again: "You can do acid music with any instrument. You can do it with a live band, you can do it with anything. It's not just the 303 that makes it acid. It's the concept, the setting of moods. Any music that sets a mood, I guess you could call it acid music.

"Once people understand that you can do acid house music with any instrument, that you can set a mood with anything, then that's when you can do it in any part of the world. You're going to hear African acid, Italian acid, Indian acid. Indian has already got acid."

Ironically, the only bona fide overground "acid" hit, D-Mob's chart-topping 'We Call It Acieed', steered clear of the 303 - most of the parts were played on a Prophet VS (also, the track was more techno than acid, despite the dreaded acid chant).

Acid music now seems to be mutating into "hip house" (acid with hip hop techniques) in the music of such Chicago musicians as Fast Eddie and Tyree. Both are still using the 303, so maybe it will survive in contemporary dance music after all.

Now seems to be renaissance time for old analogue synths in general, and providing the 303 can transcend the "acid" tag, it should retain a niche for itself. To paraphrase Bam Bam: it's one thing having a 303, it's another thing being able to make interesting music with it. But there's no reason why today's musicians shouldn't carry on doing just that.