YUPPIES HAVE THE Psion Organiser. Students have the programmable calculator. Schoolkids have the handheld Space Invader game. And even poor beleaguered journalists have the portable word-processor. But what is there for the 'umble musician to play with on the train home from work?

Perhaps these two gadgets from Akai will fit the bill. On the table in front of me are a couple of small grey boxes, beeping quietly in unison: the U1 and U2, Beat Calculator and Programmable Rhythm Trainer respectively. Designed with the "young musician" in mind, these two thingies (for want of a better word) represent a giant leap forward from the crude electronic metronomes that branches of Minns Music used to give away free with toy keyboards.

At first glance, it's not obvious exactly what they're for. Take the U1. It's described as "an electronic calculator for music with a built-in metronome and stopwatch". Come again? Look at it this way: fed the right information, the U1 can calculate various figures crucial to putting a song together that would otherwise take a pen, paper, calculator and degree in Maths to work out.

Say you've written a song with a 16-bar intro, five 16-bar verses, seven 16-bar choruses, eight four-bar bridges and a 32-bar instrumental jam. That makes 272 bars in all, and (in all likelihood) one helluva mess. The tempo, you feel, should be round about 126bpm (beats per minute). How long will the song last? With the U1 in Metronome mode, easy - 8 minutes, 38.09 seconds. Alternatively, say your band happens to be practising along to the metronome and you want to write out a song chart for the new sax player. Press start and watch the U1 count up the bars. As the rest of the band play, you can note down: Bar 0, Intro; Bar 8, 1st verse; Bar 16, Bridge; and so on - just by keeping an eye on the display.

In "Step/ms" mode, the U1 allows you to calculate note durations. For example, at a tempo of 154bpm, how long will a dotted quaver last? Simple, 292 milliseconds.

The Beat Calculator is particularly handy for use with a digital sequencer. For example, say you're working on a sequence with the resolution set to 48 pulses per quarter note (or "ppqn" as they say in the trade). You want to work out the number of pulses an eighth-note triplet will be? No problem: set the little grey box into "Time Base" mode, press a couple of little grey buttons, and Bob's your little grey uncle - 16. One less headache to anyone for whom Maths is a mystery...

One of the most tedious chores that faces DJs and songwriters is calculating the tempo of a track in beats per minute. Either you have to sit down with a drum machine and correct the inbuilt metronome until the speed sounds right, or you have to count beats for a minute - both time-consuming processes. The U1 can calculate the bpm of a rhythm as you tap along to it. It's simple and effective. And if you think your finger-tapping is the most accurate this side of Bobby McFerrin, the U1 will bring you crashing down to Earth: as the display changes radically with every tap, you realise just how difficult it is to keep a regular beat...

Though the machine is generally well designed, one or two puzzling problems rear their ugly heads. First, the bars count up from zero: if you're used to calling the first bar "one", this can get confusing. And what band leader in their right mind would count-in a song with the words "Are you ready? Nought, One, Two, Three"? Obviously, someone at Akai in Japan does. The buttons are fiddly, and the most important one, the Start/Stop/Tap button, is very easy to mis-hit - particularly annoying when you're calculating tempo in the Tap mode. And, speaking as a DJ, it would have been useful had the sensitivity of the metronome allowed you to go down to a quarter of a bpm.

Like the supergroup of the same name, the U2 is very much pitched at a particular market: that of the young musician who wants to become "rhythmically aware" but has no need of a drum machine. Even more than the U1, the Programmable Rhythm Trainer is a turbocharged metronome: its main use is to provide a click-track for rehearsal or recording.

In Manual mode, a pattern of between 1 and 24 steps may be set up. The metronome can be set to beep in quarter-notes, eighth-notes, eighth-note triplets or 16th-notes. The first note of the pattern is an accented, high-pitched beep to let you know you're at the beginning. The rest are a standard low-pitched beep, a mid-pitched beep for accents, or a space (no beep at all), depending on what you choose to program. Thus, simple rhythms can be set up to imitate bass drum and snare or shaker parts. This, as any musician who has worked to a "click" will tell you, can only be good news because the "fuller" the rhythm of the metronome, the easier it is to keep time to.

The other modes available on the U2 are standard four-beat, eight-beat and 16-beat beep rhythms, useful for swiftly setting up a metronome to work with, and a Tap mode similar to that on the U1.

Incidentally, both the U1 and U2 have a quarter-inch jack socket for connection to an external amplifier (the onboard beep wouldn't disturb a mouse, let alone be heard over a drum kit) and a 9V DC socket is included for use with a mains transformer instead of the standard batteries.

It's not until you sit down with either of these machines that you realise just how useful they can be. Both obviously perform metronomic duties essential for any self-respecting musician, but they're really in a different league from most similar accessories - a fact that's reflected in prices that are a touch on the high side.

The U2 might be considered a Rolls-Royce among clicking brethren. Yet the U1 is my favourite of the two: anything that minimises the maths involved in programming drum machines or sequencers is welcome to sit on my lap on the 4.35 from London...

AKAI U1 BEAT CALCULATOR, £69; U2 RHYTHM TRAINER, £49; both including VAT

INFO: Akai Professional, (Contact Details)