Having established a particularly convincing grip on the musical instrument and home recording markets, those nice chaps from Yamaha are now apparently looking to plant their vice-like mits about the world of professional digital studio processing. To this end they have launched a small but ever growing range of very high class, state-of-the-bank-balance, top-of-the-morning processors such as the YDD-2600 delay and the REV-1 digital reverb system costing a rather immodest £7,588.

At the other end of the Yamaha scale we find what is currently the cheapest digital reverb system on the market — the R1000 going out at £566. For the price the R1000 is very good, but it is limited to straight reverb, and effectively to two decay time settings. Very few people, and relatively few studios, will be able to afford the REV-1 but will want a little more sophistication than is offered by the R1000, thus we find ourselves presented with the new Yamaha REV-7 filling the gap at £1,199. Incidentally, this is a little less than the new Roland SRV 2000 digital reverb which comes out at £1,375, which you'll find under review elsewhere in this issue.

The REV-7 has two electronically balanced analogue inputs and outputs on both three-pole jacks and XLR connectors. A mix control on the front panel allows adjustment of the balance between the direct signal (straight through from the inputs) and the effected signal emerging from the depths of the processing circuitry. When used in the stereo mode, eg when connected between the stereo outputs of a mixing console and the crossover/power amp circuitry of a PA system, the direct signal from the left input goes to the right output and the left to the left in true stereo fashion. If you are working with a mono source, however, such as a mixer's echo send or a single output synth etc, a mono switch allows both the outputs to be fed by the direct signal from just the left input. There is only one channel of analogue to digital conversion, and so a stereo input signal is summed before being processed, and all 'stereo' effects are simulated as part of the process, before being sent to the stereo analogue converters. I mention this as a matter of information, because people often seem to get confused over the idea of stereo reverb; it's certainly not a criticism of the REV-7. Most digital reverberators actually only have but a single mono analogue input, and you have to get into the realms of the Lexicon 224X costing more than 10 times the price of the REV-7 before you get two completely separate channels, thus the REV-7 is better than most in that respect. In fact with a stereo EMT Gold Foil echo plate the separation between channels is only 6dB, and so there is a good degree of summing there also.

The REV-7 has 30 factory preset effects plus a bank of 60 'non-volatile' (ie the memory doesn't die when you turn the power off) user memories for storing your own presets. In anticipation of the fact that for much of the time people will simply want basic hall, echo plate or fastening effects, the first six factory presets offer two halls, two plates and two single reflections and each can be quickly recalled at the touch of its own dedicated button. Thus to use this box in its most basic mode, you need have virtually no knowledge of it or the nature of reverb at all.

The Numbers

The REV-7 uses 16-bit linear quantisation with a sampling rate of 31.25kHz (incidentally the MIDI Band rate) yielding a 12kHz audio bandwidth and a dynamic range of 78dB (reverb) and 84dB (delay only). It isn't limited to straight reverb, it can also produce chorus and flanging effects and stereo repeat echoes. In terms of reverb programmes the basic programmable parameters include:

Pre-Delay (0.1 to 100ms) — the time delay between the direct sound and the onset of reverb.

First reflection (delay 0 to 100ms, level 0 to 100%) — a single mono repeat echo after the direct sound, before the reverb. This repeat is available on other effects apart from reverb, such as flanging or chorus, and can always be used to give an ADT or doubling effect. A good example would be to fatten-up a snare using an ADT delay of 20ms with the reverb coming in 60ms later. It's jolly effective.

Reverb time (0 to 10 secs) — adjustable in two frequency bands to simulate different acoustic absorbency characteristics of a room.

Diffusion (0 to 10) — the complexity of the reverberant sound giving either fewer, more defined reflections, or a smoother more complex diffuse liveness.

Stereo Repeats — when producing repeats, it is possible to enter independently the delay times for the left and right outputs up to 450ms, effectively causing the repeats to jump to and fro across the stereo image.

Modulating That Time Domain

A built-in LFO (low frequency oscillator) makes possible the chorus and flanging effects. In these 'non-reverb' modes the same buttons that would adjust reverb time, pre-delay, etc for a reverb programme are used to adjust modulation speed and depth for both delay and amplitude, the feedback gain to deepen the churning and the delay between the left and right channels which also alters the overall effect.

Before the signal even gets sent to the digital processing section, it goes though a three-band sweepable equaliser allowing you to give it +/-15dB between 50Hz and 15kHz. This only acts upon the effects signal while the direct signal remains untouched. Bypass buttons are provided for both the eq and the complete system.

A huge bonus for live work is the MIDI facility which is becoming more or less standard on programmable effects equipment at this level. The REV-7 can be addressed on any one of the 16 MIDI channels in order to link the selection of another MIDI instrument's voice presets with the automatic selection of one of the REV-7's effect. There is also a small cabled remote control unit that allows any of the 30 factory presets to be called up plus the first seven of the userpresets.

The REV-7 offers a very high degree of control and is relatively simple to operate after a little practise. So what is it that the REV-1 has that the '7 doesn't? What will you find yourself lamenting the absence of once you really get into the thing? The REV-1 has generally superior technical spec with a sampling rate of 44.1 kHz, and 18kHz bandwidth, better noise figures and longer delay/reverb times. It also offers more detailed control of the effects parameters, both directly and from a very comprehensive remote control. It also has a direct digital audio interface to avoid unnecessary conversion plus an RS-232 serial computer interface for use with micro computers. The REV-1 is undoubtedly more powerful and offers generally better quality, but it does fall under the law of diminishing returns and for most home and studio users the REV-7 will be more than adequate and the difference won't warrant the huge extra financial outlay.

The REV-7 is a 2U (3½") 19" rack mounting unit and is in appearance closer to the REV-1 than to the R1000 with an air of quiet sophistication that would look good in any studio. A back-lit LCD display gives clear indication of the name of the programme or the parameter being adjusted, while a larger LED display shows the number of the current programme.

Conclusion

A great deal is offered here for a relatively small price tag. The quality of the reverb is smooth and clean, and the scope of the available effects is wide. Without having looked closely at the new Roland system it's hard to say whether the REV-7 has any competition at the price, because apart from the possibility of the Roland, it stands alone.

For: High quality, high degree of control; MIDI; good value.
Against: No facility to name user programmes; no tape dump for programme data.

YAMAHA REV-7 DIGITAL REVERBERATOR — RRP: £1,199