Not for the first time, tomorrow's technology is being used to recreate yesterday's sounds. This time the sound is echo, and the results are staggering.

FIFTEEN YEARS AGO, a young musician began buying musical equipment. He was a keyboard player, but he could have played any instrument. At the time he was still at school, so he couldn't afford particularly good keyboards - in fact, by today's standards they were awful. As he became steadily better off he started buying some very "professional" synths but, although he worshipped such mega-groups as Genesis, Pink Floyd, and ELP (these were the mid-1970s, by the way), he just couldn't get the "professional" sounds he wanted. By the end of the 70s he had enough gear to start a music shop, but none of it sounded as good as it did when played by the pros.

Then one day his PA amp packed up and he had to plug his mixer into a guitar amplifier. Shock! Horror! His keyboards sounded brighter, clearer, punchier... He wasn't sure whether to laugh or jump into the nearest river. He'd finally achieved the sound he'd been seeking, and at the same time realised that he could have saved a couple of thousand quid. The difference that had eluded him was this: a £200 synth with reverb and echo often sounds better than a £2000 synth without it. And waddya know? The guitar amp had a spring reverb and a primitive echo unit built in.

For our young hero, the next stage was to try out the reverb and echo units that were available at the time, and the best of these turned out to be a tape echo unit with a spring reverb - called the Roland RE501 Space Echo.

The original Space Echoes (the RE201, 301, 501, and the rack-mounted SRE555) were arguably the most successful effects units ever produced. But modern developments in digital technology made them obsolete, and the range was phased out in 1985. However, demand for the RE-series continued, and secondhand (tenth-hand?) units still change hands today for £200-300. Many musicians claim that the characteristic warmth of the Space Echo tape system was lost when Roland "went digital", so the company have decided to produce a digital version of the Space Echo - warts and all.

The result is the RE3 Digital Space Echo, which is claimed to have all the desirable qualities of the original. In fact, Roland have adhered to the original concept so closely, not one additional effect is available on the RE3 than was provided on its predecessors.

Issue 4 of PHAZE 1 should have introduced you to the basics of echo and reverb. In case you missed that, echo is the sound that you get when your original signal (eg. you yelling "I hate Bros" at the top of your voice) is reflected back to you by a solid object (eg. the Matterhorn) in such a way that the original signal content can easily be discerned ("we hate Bros too", echo the mountains). On the other hand, if there are so many reflecting surfaces that the sound is bounced back at you in many different ways (eg. in your bathroom) you get a quite different effect made up of lots of little echoes, known as "reverberation" or reverb for short. This creates an "envelope" around the original signal without which your ear, and therefore your brain, is quite lost.

So reverb is the most important effect available to a musician. Echo is less noticeable in nature since most natural sounds are not subject to pure echoes, but as a musical effect it is still extremely important. For some sounds, such as guitar and vocals, a touch of echo can be very useful in bringing a track to life.

Today, many digital effects processors cost only a couple of hundred quid, and it's tempting to think of all reverb and echo units as essentially the same. Fortunately this is not the case: the sound quality of effects units can differ widely from one manufacturer to the next and, indeed, from one model to the next.

This month's Dream Machine is an effects unit which, for many musicians, could provide the most pleasing reverb and echo effects currently available.

The RE3 is a digital effects unit combining a number of echo effects with a reverb generator and a simple chorus-type effect. It introduces very little unwanted hiss or distortion, but the reverb has only one parameter, which Roland call "Depth", and which varies the amount of reverberation added to the treated signal. The final effect, called "Warmth", adds a modulated component to the signal. Input is in mono only, but the RE3 has stereo outputs and is capable of some delicious spacial effects. However, it will still work perfectly well in mono - into a guitar amplifier, say.

The control panel has been kept simple. On the left are two microphone inputs with associated gain controls. Across the middle of the panel are the various controls that determine the nature of the effect and, bucking the modern trend of making echo units look like the flight deck of the Starship Enterprise, the RE3 offers only five parameter control knobs for its entire system. In addition there is a pretty LED input level indicator, a 10-character LED display, four buttons for accessing the memories (amongst other things) and, of course, the all-important on/off switch.

The five effect control knobs are probably the simplest yet seen on a digital multi-effects device. They are: echo level and echo rate controls, echo intensity (which increases or decreases the number of repeats in the treated signal), reverb control (increasing the amount of reverb), and "Warmth". To modify any effect, you simply turn one of the control knobs and the screen on the front panel (which normally shows the mode and memory selected - see below) changes for a few seconds to show the parameter name and its current value. With a little practice, you can quickly create and experiment with new effects.

Nearly all modern effects units have the means to store your favourite settings, and recall these at the touch of a button (or two). So if you have a clear, bright sound for general vocal work, a long echo with lashings of reverb for your Enya impersonations, and a moody, modulated effect for guitar, these can all be stored in the system's memories. The recent trend has been to add more and more memories to units like the RE3, to allow you to set up more of your own sounds. Unfortunately, most musicians only use a few sounds, and consequently waste a lot of money on facilities they never use.

But once again, Roland have decided to buck the trend, and instead of endowing the RE3 with an enormous storage capacity, have given it just five "modes", each of which has five memories.

Now, the original Space Echoes worked by passing a section of magnetic tape around a series of heads in a continuous loop. An incoming signal would be recorded on the tape by a record head (just like the one in a cassette recorder), and would pass over a number of playback heads (just like the ones in a cassette recorder) before being partially or totally erased by an erase head (just like the one in a cassette recorder). Because the playback heads were not equal distances apart, and because the tape was moving at a constant speed, a number of different echo effects could be obtained by using different combinations of the playback heads available. These combinations, which could be selected by a rotary knob, were known as "modes", and the RE201 (the cheapest in the range) had 12 modes of operation: four pure echoes, seven reverb echoes, and one pure reverb.

By comparison, the new RE3 has the five modes already mentioned, each with a subtlely different character. These are: S.Echo1 (single echo with reverb), S.Echo2 (panning echo with reverb), S.Echo3 (mixed echo), R.Echo1 (straight reverb), and R.Echo2 (bright reverb). Modes 1 and 2 use all the effects available on the unit, mode 3 has no reverb but an interesting irregular echo, and modes 4 and 5 are built from a combination of reverb and "warmth", with no echo.

Learning to use the system is dead easy. And crucially, you don't get the feeling that you'll never quite get the best from the device because either (a) you haven't got enough time to experiment with it or (b) you don't have a degree in Electronic Engineering.

Now to the important bit. It is just about impossible to describe sounds accurately with words, and even more difficult to explain why one sound is better than another. Looking objectively at the RE3, it can hardly be described as cheap. And it's certainly not an all-singing, all-dancing effects processor capable of reproducing every sound effect known to modern music. But it is marvellous to listen to. It simply makes everything sound nicer - clearer, brighter, and punchier than perhaps any other unit available. As it happens, the range of subtle "Space Echo" effects is quite staggering, and it is these variations on the theme of subtlety, combined with excellent sound quality, that are the machine's true strength.

The RE3 Digital Space Echo performs faultlessly, creates an instantly recognisable and much-loved effect and, for what it does, costs The Earth. For £600 you could buy a complete Boss Micro Rack with reverb, delay (including chorus, flanging and so on), and a choice of distortion, compression, limiting, graphic EQ, and others.

But though you may hate the size of the hole it makes in your wallet, you'll never complain about its sound quality or the unique feeling of life it brings to your music.

And as for the poor, foolhardy musician I told you about at the beginning of this review - well, he just wouldn't be without one, would he?

ROLAND RE3 DIGITAL SPACE ECHO: £599 inc VAT

INFO: Roland UK, (Contact Details)