Take it easy now — what's this? Let's not panic, but it looks like a new digital drum machine. It's too cheap, of course. It's too smart as well. And haven't we heard about it before? A long time ago? Maybe. Ah, it must be from Yamaha.

Even for a company who've given new meaning to the phrase "don't hold your breath", Yamaha have excelled themselves here. It's just too naughty to keep such good things from the public for so long, allowing only tentative glimpses and quick peeps. And another thing. You can be sure the RX15, and its larger brother the RX11, will be in short supply even when they do get into the shops because, when all is said and done, they're really jolly good.

Why are the two RX models cheaper than any other digital drum machine on the market (apart from Syco's dinky plastic MFB 512)? Basically because they use PCM samples, which are a little more straightforward than digital recording and so keep costs down. The disadvantage is that it's not easy to read PCM samples back at different speeds, and so you can't tune any of the drum sounds on the RX15.

The sounds themselves are pretty good though. The Bass Drum is neat and thumpy without turning into an electro-funk mess, the Snare is sharp and versatile with a bit of EQ, the three toms are not too short — pretty powerful but not overbearing. Hi-hat open and closed are very accurate, no sign of hiss or distortion, and the Ride Cymbal is a pleasure — a good thump on the bell with plenty of lifelike stick noise. The Crash Cymbal is deep and powerful, the Clap is a Clap (what can you say about a clap? They're all synthesised anyway), and the Shaker and Cowbell are neat and to the point. All the cymbals cut off a little early, but not too suddenly — the effect wouldn't be noticeable inside a pattern with a bit of reverb added.

So, a total of 15 sounds (a higher-pitched Snare and Pedal Hi-hat are hidden away) and only two outputs, between which the sounds are pre-panned unless you alter their position by holding Pan and moving the Data Entry slider. The RX resembles the DX synths in that most changes are made with this single slider control, and a 16-segment LCD display (as dark as on the DX7) shows you Tempo, Pan Position, Time Signature, Pattern Number, Song Number, MIDI mode and all the other 101 things you've always wanted to know about the inside of your drum machine.

There are several methods of entering new patterns, up to a maximum of 100 patterns and 10 255-part Songs. There's step time, real time corrected up to 1/192 of a bar, and the exotic keyboard method. This involves a DX7 or similar plugged into the RX's MIDI In port. Playing a selection from the bottom octave of the keyboard will program your drum machine for you in real time, with dynamics added by the keyboard. Alternatively, you can reverse the MIDI leads and use the RX as a mini polyphonic sequencer for one octave of DX7 notes — great fun, this MIDI business. For those of you without a DX7 (is there anybody without a DX7 apart from thee and me?), accents can be added to patterns on the RX after programming.

While we're thinking about the back panel of the RX, let's mention that there are Tape Sync facilities, footswitch Start/Stop and headphones sockets and a fixed power cord. There's a very comprehensive manual which is written in tiny script sufficient to give "War And Peace" fans a headache, and a peculiar mains cord (on our review model anyway) which needed an electric shaver-type adaptor before doing the business. Apart from that, few complaints on presentation — the thing's thin and sinister, slightly wedge-shaped, matt black and very smart sitting next to a DX7.

The RX is not difficult to use, but you do gain the impression that Yamaha have made the layout more complex than necessary. All the buttons have two or three functions: there are DX7-type -1/No and +1/Yes buttons where surely Sequential Circuits-type Up and Down would have done nicely, thank you. Apart from that minor quibble there's nothing missing that the competition could offer — you can introduce a variable Swing from 54 to 71%, produce a metronome click, copy from one pattern location to another, repeat a pre-defined section of a song for as long as you like, define tempo for each pattern within a song, clear patterns and songs in one go, verify tape saves, redefine the MIDI channel and instrument assignment to MIDI notes and so on.

The question arises as to whether the RX machines are a case of too little too late. In some senses they're a bit limited. You can't tune the sounds or insert new sound chips as you can on the SCI Drumtrax, currently the biggest seller, and it's annoying that the 15 doesn't have individual outputs (possibly a cheap modification though — and the 11 has 29 sounds, individual outs and memory dump to RAM packs).

On the other hand the RX machines are smart, accessible and cheap. Let's face it, they're going to sell in disgustingly large numbers. Put your order in now for 1985.

Yamaha RX15 drum machine: £449