With the help of 28-bit processing technology, Roland have introduced a signal processor that can generate digital reverb, delay, chorus and flanging effects - and combine them together to produce new treatments.

WHAT A DILEMMA. Here I am, with a 1U-high, rack-mountable multi-effects unit, and no earthly idea how to start the review with any phrase other than "Roland's DEP5 is a 1U-high, rack-mountable multi-effects unit - with a difference". I know. I'll start it with "What a dilemma"... If it's a fault, make it a feature, as they say. But I still wish modern effects processors would come in different formats, other than the standard one.

Anyway, the difference just mentioned is that the treatments the DEP5 produces can be used in combination, as well as singly.

Essentially, there's a classy digital reverb, gated or reversed reverb, delay, stereo chorus and three-band EQ. There are four different basic reverbs to choose from with variations on each, in addition to gated or nonlinear types, and all have a 12kHz bandwidth. The converters are 16-bit, giving low noise and distortion, and the internal processor handles 28 bits.

Acknowledging the fact that there are a lot of ways you can use these effects, Roland have given the DEP5 a total of 99 memories - including 29 preset effects - all of which can be called up via MIDI as well as from the front panel.

You don't, however, get to choose exactly how you configure the different effects sections. Instead, you have to select from 11 possible flow algorithms, and then set up your own parameters. Because of the way in which the effects can be internally configured, it's worth devoting a few lines to examining those algorithms in detail.

Algorithm 1 is stereo chorus only, while number 2 is reverb only. Number 3 is stereo reverb, the output of which is treated to give pitch modulation effects. Algorithm 4 gives a chorused reverb, number 5 has the reverb and chorus in parallel rather than in series, while number 6 is very similar to the previous algorithm, but with a stronger chorus element. Number 7 is gated reverb, 8 is gated reverb with modulation, and 9 is a parallel combination of non-linear reverb and chorus. The delay section makes an appearance in algorithm 10 in parallel with reverb, while number 11 is described as being low density, non-linear reverb with modulation.

So, with the exception of EQ - which can be set up for all algorithms - no more than two effects can be operated simultaneously. This dispels the myth that the DEP5 lets you use all your effects at once, but the machine does have some powerful surprises in store.

The delay section, for example, has an impressive maximum time of two seconds, while the reverb can be adjusted all the way from an almost immediate decay to a huge 99 seconds' worth. It's also possible to program the number of repeats for the delay program, and stereo delay effects are available.

Controls

THE NICEST THING about the control section is that the DEP5 actually has one. Yes, there are knobs for everything that you might want to twiddle, and that's good news. One odd feature, though, is that the power switch doubles as the effects bypass. Now, I've heard of economising on electricity, but that is ridiculous; it must have been designed by the sort of person who switches off their windscreen wipers going under bridges...

Anyway, from left to right we have a bar-graph level indicator, followed, not surprisingly, by the input level control which Roland have decided to call the Input Attenuator. This doesn't actually turn down to zero, which is an odd arrangement.

Next is the dry/effect balance control, which would probably be set to effect only for use with a mixer. For use with an instrument amplifier, though, this control is used to set the depth of the effect.

The next three controls are dual function in true Roland tradition, but don't panic; their operation is very logical. In one mode, they control the three EQ bands, providing up to 12dB of cut or boost at 100Hz, 10KHz and across a parametric band sweepable from 300Hz to 12kHz. When not handling the EQ, they control the chorus rate, depth and feedback.

The next control is in fact a rotary switch, which should appeal to Spinal Tap fans because it's calibrated up to 11. This selects the desired algorithm, determining which effects are active and in what order they are connected.

Reverb parameters are set up by the following three controls. They set the Pre-Delay time, the Reverb Time and the HF Damping. In non-linear mode, they also control the effect duration. Then there's the Reverb Selector button, which allows four different basic reverbs to be called up. These are Room, Hall, Plate and Special - more of Special later.

We mustn't forget that gated reverb is on offer, and that it's possible, using the non-linear programs, to create backwards type effects, which the manual doesn't really stress.

The memory number may be stepped up or down using a button to the left of the display, and the display itself shows a lot of useful information - including the current memory number, the parameter value currently being adjusted, and the effects that are active for the current algorithm. In reverb mode it shows the room size, while MIDI information also comes up here when the MIDI parameters are being edited; these include MIDI channel number and mode. Program numbers can be assigned to MIDI patch numbers in the range 0-127, so you don't have to reprogram all your effects from scratch to get them to match up to your synth programs. And as you might expect, you can select any of 16 MIDI channels or select Omni mode.

On to the bank of buttons to the right of the display. The Reverb Selector button we've seen already, but the next row contains the Write and Chorus/EQ select buttons. Write is used to lock your memory and the other switch, as its name implies, selects whether you're editing the chorus or EQ parameters.

The Output Level control is used in conjunction with the Reverb Selector button to program the output level of each effect. This is A Good Thing, especially while so many manufacturers are still overlooking the fact that you don't want all your programs to be implemented at the same level. You can also program a different effect balance for each memory - essential for stage work, but again, still absent on some programmable effects units.

Fortunately, there's an alternative to switching the power off if you want to bypass the effect - you can use a footswitch connected to the socket provided. A footswitch can also be used to step through the first eight program memories in ascending sequence. The ninth switch operation returns you to program memory 1. There's MIDI In and MIDI Thru, but no MIDI Out, as the DEP5 can only take orders, not give them.

Sound

THE MOST EXPENSIVE part of a unit like this is the reverb, and it's on the quality of this that the success of the DEP5 largely rests. As I've already stated, there are four basic reverb types, and the rooms and halls offer a choice of room sizes - from shoe-box to the Royal Albert Hall in sensible increments. The plate setting has two options, as does Special.

The basic reverb sound is bright and reasonably smooth, but slightly metallic. It is, however, a good deal more flexible than most budget reverbs. In a mix the slight colouration is not a problem, and the reverb succeeds in sounding good on both percussion and melody instruments. By comparison with a more sophisticated reverb, the effect is a bit low on diffusion, the decay tail is slightly cyclic, and the overall effect is a little unrefined. Even so, it still sounds great on pop music productions, and that's where its main market lies.

The rooms and halls are effective and fairly convincing, while the plate is very bright indeed. The pre-delay helps to make the sound more interesting and adds to the sense of space, with the HF damping helping to give a more natural sound. And these days, being able to change such parameters at the twirl of a knob is little short of total luxury.

The gated and non-linear sounds are good, too, and there's a surprising variety, from snappy gated drum treatments to eerie, reversed effects. Both gated and reversed settings can be varied in length, and there's one low-diffusion gated effect that sounds terrific on handclaps. Some of the non-linear sounds have a built-in panning effect, too, which can be quite spectacular.

The Special reverb setting is decidedly odd, though. It has a strange high-frequency frying sound to it which can be really stunning on some sounds, but totally inappropriate on others. Using this setting, I got one percussion treatment which sounded as though someone was hitting a hot metal plate onto which cockroaches were being dropped at regular intervals. A bit obscure, I know, but it's the only way I can describe it properly.

When the reverbs are combined with chorus (or with feedback flanging), the effect can vary from subtle to monstrous - but in all cases, the result seems to be far more than just the sum of the parts. These treatments seem to be aimed at keyboard players: the cheapest synth can be made to sound deceptively PPG-ish, and flanged, reversed reverb on a bland strings sound can transform it into something a Series III Fairlight would be proud of.

The chorus used on its own is all that we've come to expect from Roland; they were the first people to develop it as a serious effect, after all. It's bright, wide and thoroughly dynamic...and a twist on the feedback control instantly transforms it into vicious flanging.

The delay is surprisingly effective when several repeats are programmed, and here too, impressive stereo treatments are available. Having the facility to use EQ really adds to the flexibility of the DEP5, and the parametric section, especially, is useful for 'peaking up' a sound.

What continues to amaze me, though, is the way all these treatments not only sound good in isolation, but can also create such intriguing effects in combination. Setting the sounds up is easy because you only have to call up a preset that's something near to what you want, and then fiddle with the controls to get exactly what you want.

Verdict

I EXPECTED THE Roland DEPS to be one thing and it turned out to be another. As a multi-effects unit, it doesn't offer as many obvious options as Yamaha's SPX90, and it doesn't have a pitch-shifter. However, it does have a respectable and flattering-sounding digital reverb which is easy to use and offers lots of options. There's a stereo chorus which may be used as a stereo flanger, and then there's the delay, which in itself offers more variety than you might at first think.

But it's the combination of reverb, chorus and EQ that yields the most unusual results. Most of these treatments work well given the right kind of input signal, and most sound spectacular when used with modern synthesisers; knowing Roland's position in the keyboard market, maybe this isn't really surprising.

Combining this machine with your keyboard gives you a totally new instrument, but you really do have to hear one in use to appreciate what it can do. In some ways, the DEP5 is an education in how various delay treatments interact when used simultaneously.

On paper, a reverb, delay, chorus and equaliser in one box no longer sounds a big deal. But once you plug the DEP5 in, it's somehow a lot more than that.

Price £675 including VAT

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