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Yamaha Rev500

Reverb Processor By Hugh Robjohns
Published March 1997

The modest £399 price tag on Yamaha's latest dedicated reverb belies the quality and controllability the unit offers. Hugh Robjohns thinks it's up there with the best.

Many home studios have a Yamaha multi‑effects unit stashed away in a rack somewhere. On a strictly value‑for‑money basis, Yamaha's earliest efforts, like the classic SPX90, were unbeatable, although their reverb programs often attracted critisicm for their rather metallic qualities.

However, Yamaha showed that they could challenge the industry leaders in digital reverb with their professional products and inevitably, the technology and algorithms developed for these top‑end products filtered down to more affordable units like the SPX990. The latest addition to Yamaha's family of reverb machines is the all‑new REV500, which really takes the art of affordable digital reverb into the next generation.

This compact, 1U rackmounting machine comes with 100 factory programs, divided into four families (Hall, Room, Plate and Special) and there are a further 100 user memories for storing your own variants. The system's digital signal processing extends beyond 'mere' reverb to include such familiar effects as echo, tremolo, chorus, flanging, symphonic, dynamic filtering, resonator and gates.

One of the most interesting aspects of the REV500 is its new operational interface. The tedious push buttons used to locate and edit parameters, which became established with the SPX processors, have been replaced by a set of shaft encoders providing direct access to the fundamental reverb settings. The large LCD in the centre of the front panel normally displays details about the current program name and key parameters. However, when any of the four shaft encoders is adjusted, a symbolic graph of level against time is displayed to make the results of any adjustments very obvious indeed.

Plugging In

The REV500 features the same kind of interconnection flexibility that has already proved successful on earlier products. The rear of the unit carries a fixed mains lead on the left‑hand side (as viewed from behind), MIDI and remote control facilities in the centre, and audio inputs and outputs on the right.

The machine can be configured for a mono input (using the left channel socket) or a true stereo input. Connections are via a pair of XLRs or quarter‑inch jacks, both wired for balanced signals, although the jack sockets will happily accept unbalanced leads too. A slide switch adjacent to the connectors determines input sensitivity to accommodate professional levels at +4dBu or semi‑pro at ‑10dBu. The output side of the machine is similarly equipped with XLRs and jacks, again both balanced and with selectable output levels. There is no provision for digital interfacing.

Other connections include the obligatory pair of MIDI sockets, and a jack socket for an optional footswitch. The system may be configured such that the footswitch either recalls the next program memory or mutes the reverb output.

The internal analogue‑to‑digital conversion processes are carried out to an extremely high standard, with 64x‑oversampled 20‑bit A/Ds and 8x‑oversampled 20‑bit D/As (operating at 44.1kHz). As you might expect, these converters ensure that the REV500 is very quiet and the reverb tails descend smoothly to the point of silence.

The quoted specifications are all very respectable: frequency response flat between 20Hz‑20kHz (within 3dB); dynamic range of 96dB; and distortion less than 0.03%. The only thing that might cause concern is the quoted output impedance, which the handbook claims to be 150kΩ! I'm sure that this is a simple misprint and that the 'k' symbol was added by mistake — in any case, I certainly experienced none of the interfacing problems that would be expected with such a high source impedance.

The Controls

The front panel of the REV500 is very clear and well laid‑out. The left‑hand side starts with a single input level control for both channels, complete with stereo LED bargraph meter. This is a little crude, with only two columns of four lamps, labelled Clip, ‑6, ‑12 and ‑24, but it is sufficient to match the machine's input levels with the output from a mixer's auxiliary send.

The next control block to the right consists of a group of four buttons labelled Type, Preset/User, and Number '+' or '‑'. The functions of these buttons are self‑explanatory, with the Preset/User button selecting which bank of 100 memories is being used, the Type button cycling through the Hall, Room, Plate and Special categories, and the '+' and '‑' buttons navigating through the selected group.

The central LCD dominates the front panel and provides very clear information about the selected program type, program number, signal processing structure, key parameter values, program name, and mono or stereo input mode. Although there's a great deal of information shown on the display, it's not cluttered or confusing in any way.

The REV500 is an extremely good digital reverb which can hold its head up in any company. In the light of its price, however, it really is something special...

When one of the four parameter knobs is moved, the program name section of the LCD is instantly replaced with a representation of the current parameter values as a bar‑chart. The left‑hand side of the chart indicates the 'now time', and somewhere to the right is a column representing first reverb reflections. To the right of this are further columns illustrating the main body of reverb, gradually decreasing in amplitude. The display is quite intuitive and, although of no real practical use, is novel and fun to watch as the appropriate parameters are adjusted.

To the right of the display, four knobs edit the main reverb parameters: Pre‑Delay, Decay Time, Hi‑ratio and ER Level. The roles of the first two are quite straightforward: Pre‑Delay can be set anywhere between 0 and 200ms, and Decay Time from 0.3 to 99 seconds. The Hi‑ratio control sets the reverb decay time for high‑frequency sounds as a proportion of the main decay time, a value of 1 meaning an equal decay and lower values simulating the absorbent effects of typical room furnishings. The ER control has nothing to do with the number of repeats of a certain medical soap opera shown on TV (sadly), but actually sets the relative amplitude of the early reflections generated by the reverb program, on a scale of 0 to 100.

The final operational controls are four more push buttons labelled Store, Audition, Eff Level and Utility. The Store function is used to initiate MIDI bulk data dumps, as well as to save an edited reverb program into a selected user memory. The Audition button is lots of fun, as it fires off an internal sound sample (selectable between snare drum or rim‑shot and with single or repeating triggers) so that a reverb program can be easily auditioned.

The Eff Level switch has an associated LED and, when pressed, the ER Level control may be used to adjust the overall output level from the machine (or the wet/dry mix if the machine is suitably configured). The front‑panel screening incorporates a graphic sensibly linking the control knob with the button.

The Utility button accesses all manner of internal parameters and system functions, in the usual Yamaha way. Pressing this button allows you to navigate the available menus, using the Pre‑Delay and Decay Time knobs, which provide left/right cursor and up/down functions respectively. Once again, the front‑panel graphics provide a clear link between the controls and the Utility button so that operation is very obvious.


The REV500 is set up through the Utility facility, which cycles through 12 functions. These are notionally grouped into Program Edit facilities, System Settings and MIDI Utilities.

The first step in the cycle of Program Edit functions accesses the internal parameters associated with the various reverb programs and the second allows the title of the Program to be altered before storing the effect in a user memory.

The System Settings determine mono or stereo input modes, Output mode (reverb effect only or wet/dry mix), Footswitch function (program increment or effect muting), and Audition sound sample (snare/rimshot and single/repeat triggers). The legend shown on the LCD during boot‑up can be customised here, too.

MIDI utilities include configuring the send and receive channel numbers, setting the MIDI Out socket to operate as a true Out or a merged Thru, assigning reverb memories to MIDI Program numbers, and setting up a bulk data dump.

The only slightly unclear aspect of the Utility section is how to exit from it, since repeated button pressing merely cycles through the available options. The answer is to simply press any of the four program selection keys on the left‑hand side of the unit.

Configuring the REV500 is actually very quick and easy, and the use of the shaft encoders to select and edit the appropriate settings works well. The LCD always provides such clear information about the current Utility mode, the selected parameter and its value that I never really needed to refer to the well‑written manual at all.

Program Parameters

Every reverb program on the REV500 provides the four basic parameters of Pre‑delay, Decay time, Hi‑ratio, and ER level — and each is controlled by its own dedicated knob on the front panel, as already discussed. These aspects of reverb are the ones which tend to be adjusted most often, of course, so it makes perfect sense to devote permanent controls to them. However, the reverb and effect algorithms employed in the REV500 feature many more sophisticated facilities for precise manipulation of the sound. These are called Internal Parameters, accessed via the Utility button. All reverb and effects parameters may also be adjusted in real time over MIDI.

All programs share four standard internal parameters: Lo‑ratio, Diffus, HPF and LPF. Lo‑ratio adjusts the duration of low‑frequency reverb relative to the overall Decay time value set on the front panel, in exactly the same way as the Hi‑ratio control. Diffus is an abrieviation of diffusion and simply controls the apparent spread and width of reverberant sounds, on a scale from 0 to 10. The high‑ and low‑pass filters allow effective tailoring of the sound: the HPF turnover is adjustable between 20Hz and 1kHz (with a bypass) and the LPF between 500Hz and 20kHz (again, with bypass).

In addition to the parameters already described, pure reverb algorithms also offer Density (of reverb tails), Liveness (of early reflections) and ER delay parameters. The latter allows the time gap between the last of the distinct early reflections and the start of the reverb tail to be adjusted (between 0 and 100ms).

In total, every reverb program allows the user to adjust 11 different parameters — impressive flexibility by any standards, and especially so when the parameter ranges allow a very wide variety of acoustic effects to be simulated with a high level of realism.

The various combination reverb/effects programs are just as well specified in terms of internal parameters. For example, the Gate programs allow threshold level, hold time, release time, and even the side‑chain signal source to be selected (input or reverb output). The Resonator provides controls for input sensitivity, feedback, fall‑back time and reverb/resonator output balance. Comprehensive collections of appropriate internal parameters are similarly available to all of the other effects processes, so that the user always has total control of the complete effect if required.

In practice, I think it unlikely that many users would find themselves rummaging about within the Internal Parameter menus, simply because of the variety and usefulness of the vast collection of factory programs. Virtually every conceivable situtation has been catered for with the preset algorithms, and once you had become familiar with them, I suspect there would be very little impetus for internal tweaking!

In Use

Operationally the REV500 is a joy to use. The factory presets are easy to access (although a data wheel would have made life slightly easier) and offer such well‑chosen and wide‑ranging reverbs that parameter editing almost becomes an option rather than an essential stage in setting the machine up. Recalling reverb programs took longer than I expected, but will not cause problems in normal studio use.

I recall being very impressed with the improvement in reverb quality offered by the SPX990 over its older siblings (like the first‑ and second‑generation SPX90s) and although I was unable to make direct comparisons between the REV500 and the SPX990 on this occasion, I believe the new machine represents a further worthwhile enhancement of Yamaha's reverb algorithms. Virtually all the factory programs offer reverb settings which I could easily find myself using in conjunction with, or in place of, more expensive reverbs, and most without any significant tweaking of primary or internal parameters at all. The distinctive, metallic and almost aggressive sounds of the old SPX90s have long since been banished from Yamaha's range of reverbs, and the base algorithms in the REV500 have continued the trend in the direction of smooth, rich and, above all, realistic reverbs.


The REV500 is an extremely good digital reverb which can hold its head up confidently in any company. In light of its price, however, it really is something special and certainly worthy of an audition. It may not represent the ultimate in reverb simulations, but it's not very far off, and certainly offers an affordable and worthwhile upgrade from its ancestors.

The user interface is superbly intuitive and very quick to use. The four rotary controls are well designed, allowing fast and accurate parameter adjustment. On the rare occasions that I felt the need to explore the Internal Parameters, through the Utility button, the operational convenience of the four primary controls was very welcome.

The graphical reverb display is little more than a gimmick, really, and I found it rather distracting on several occasions, especially when the Hi‑ratio is set to a high value, because the reverb tail no longer appears to die away! However, the numerical readouts of the four primary parameters are very clear and informative. The built‑in snare drum sample was very handy and it acted as a reliable reference sound with which to to audition and compare different programs, establish the raw character of each preset, or to check on the effectiveness of parameter edits.

Lexicon might still be regarded by many as building the best reverb units currently available, but it seems to me that with the REV500, Yamaha are snapping at their heels! Overall then, 10 out of 10 (...and can I keep this one please?).

Room Service

Assessing the quality and suitability of a reverb unit is tricky because of the aesthetics involved — everyone has their own particular likes and dislikes, and no two sound engineers are ever going to agree on the 'perfect' reverb sound. I'm giving my personal opinions here, and you should always hear a unit such as this in action before buying, if at all possible.

The first collection of factory presets are grouped under the heading of Hall, with 17 true reverb programs, three gated reverbs, three chorus or flanged reverbs, one echo routine, and one setting which mixes the reverb with a chorused version of the direct signal. The majority of program titles give a good idea of their acoustic simulations, and where there are multiple versions of the same title (for example, Medium Hall 1 and Medium Hall 2), the first is bright and clear, while the second is softer and darker — in all but the two Church simulations which, for some bizarre reason, are the other way around!

These reverb programs replicate large acoustic spaces very well, with natural, airy qualities and a good sense of space. Some of the halls have a lovely warmth, others seem to shimmer with excited reflections, and all have interesting and recognisable characters which add a real three‑dimensional aspect to any sound source when carefully balanced.

The second collection of factory programs come under the heading of Rooms, with 22 straight reverbs, one chorus/reverb mix program, one gate, and one dynamically filtered routine. Once again, many of these programs are superb — I particularly enjoyed using the 'Wood Room' and 'Room Ambience' presets, both of which worked well to add a natural acoustic to re‑voiced dialogue in a television post‑production session.

The next set of programs go under the generic title of Plate, with 20 reverb routines, a chorus/reverb mix program, an echo setting, one gated reverb and two symphonic/flanged reverbs. Having been fortunate enough to have used genuine plate reverbs on many occasions, I was very interested to see how close these replications would be and was pleased to find that many are very good indeed. The closest to my recollections of the real thing is somewhere between the 'Basic Plate' and the 'Beauty Plate'. All the Plate programs are eminently useable, and the wide variety of presets allows the perfect match to be made between source material and reverb, often without having to delve into the inner parameters at all — a tweak of the pre‑delay, decay time and hi‑ratio was all that was usually needed to extract excellent results.

The fourth set of factory programs is gathered under the title Special, all but one of which are combination effects. Limited time prevented me from a detailed exploration of these programs, but I was left with the impresson that some could be very useful in the right situations. One in particular captured my interest — the 'Pan Feedback' program. This algorithm applies reverb to the output of an echo process, but the intriguing thing is that the feedback has been arranged to increase for sources closer to the edges of the stereo image, giving a very interesting effect indeed.


  • Affordable.
  • Easy to use.
  • Sounds the business.


  • None at this price.


Well‑designed machine with excellent ergonomics and superb sound quality. Reverbs are believable, rich and detailed, with wide scope for fine‑tuning.