Lexicon PCM 90

Digital reverberator

Lexicon PCM 90 Digital reverberator

Review by George Shilling

Lexicon's top of the range 480L and its predecessor the 224X have for over ten years been held in the highest esteem. No high-end studio looks complete without the familiar LARC remote control on top of the mixer. Studio owners feel obliged to equip with one or more of these vastly expensive reverb units, which is perhaps due to prestige as much as sound quality. With these points in mind, it was very interesting to evaluate the PCM90. This unit, although significantly cheaper than the 480L, is Lexicon's latest dedicated reverb unit aimed at the higher end of the market.

Yamaha popularised assignable controls with their DX7 synth. (Eh? I thought this was a reverb unit review! <= editor's/reader's voice.). Ever since the DX7 took off, equipment manufacturers have not felt obliged to put more than one or two knobs on anything, from synth modules to reverb units. This is understandable, from a cost point of view, and also from a practical and technological standpoint. More and more features are added to each new model, which remains the same size or smaller than its predecessor. However, there comes a point where the user says "Enough!" This has already happened in the synth market, where Roland now market synths with lots of knobs, switches and sliders alongside their more "modern" units. This is also starting to happen in areas of the outboard effects market, such as the profusion of valve-based effects and other retro effects such as the Mutronics Mutator. However, reverb and multi-effects units have yet to veer away from their path along the road to assignability hell, and the Lexicon's PCM90 is possibly the worst offender I have encountered! There are two knobs on the front panel, labelled Select and Adjust, and nudge buttons for going up and down in the menus. These are what you use to do almost everything on this unit, and there is an awful lot you can do.

The operating system and layout of this unit closely resemble the PCM80, which I reviewed in a previous issue. Since I reviewed the PCM80, that particular unit has undergone some minor changes: the rear panel now sports XLR output connectors, and combined jack/XLR input connectors. The rear panel of the PCM90 is identical, and the only difference at the front is a slightly different paint job. This deep 1U box has a sturdy feel, and is truly feature-packed. A PCMCIA card slot on the front panel can be used to store edited effects if you run out of internal registers (which have 100 locations) or for new preset/algorithm cards issued by Lexicon. They have recently made available a card which features split programs and Dolby Pro Logic Surround effects. Cards issued for the PCM80 will not work.

Unlike the jack-(and master?)-of-all-trades PCM80, this box specialises in reverberation. Lots of it. There are, (like the PCM80), 250 presets across 5 program banks. These are logically divided into Halls, Rooms, Plates, Post and Splits. Each bank is then subdivided into groups of ten programs for different types of application, such as Live Sound, Vocal, Instrument and Spacial. In order to make finding suitable programs quicker, Lexicon has introduced a new feature on this unit which enables a "KeyWord" search. This appears after the last program bank. The default setting gives you an A to Z listing by program name. When you get to Z though, you cannot carry on through to A again but instead have to wind the knob all the way back. You can easily change this listing to one based on one of the KeyWords such as Acoustic, Bright, Keyboard, Large... There is a long list of keywords, and four spaces for user settings. Each preset is assigned up to four KeyWords for this purpose, and of course these are fully editable. Another feature not found on the '80 is the History of Effects Loaded which memorises the last ten effects loaded into the unit, useful for backtracking where you have been.

There are other small differences from the PCM80 operating system, such as the way the programs scroll through the different banks continuously instead of staying on the same bank. Also, the Adjust knob, (which has been assigned one main parameter of each program) shows a slightly more explanatory display when turned. There are still two edit modes: Go and Pro, with Go mode controls chosen to be the most useful for any given program. On the PCM90 some parameters are now customised with the new Custom Controls with cute graphical displays of their adjustments and amusing and helpful descriptions as they change. Ranges of adjustment can also be defined to give, say, five different filter frequencies. There is provision for four of these Custom Controls for each preset..

All of the effects are derived from one of four algorithms: Random Hall, Ambience, Rich Plate, Concert Hall, and Chamber/Room which provides two independent reverbs by virtue of the two Lexchip 2 processors. Lexicon's designers have worked hard to make these algorithms mimic the sound of the real space, and heard with a solo instrument in isolation they are very convincing indeed, with all the smoothness and lack of grain that you expect from a top-of-the-range reverb unit. Although all programs are primarily reverb-type effects, the algorithms include EQ, delay and modulation adjustments. The Concert Hall algorithm includes a digital compressor, where, oddly, you set a threshold level below which signals are boosted. You also have the full Output Width control of the PCM80 which gives you infinite adjustment of stereo image and phase. "Spinning Room" for example modulates this control, rapidly inducing nausea(!), but rather uselessly fading in and out when Mono'd. Not included on the PCM80 but featured here is a corresponding Input Width control which for example could be set to 90 to exclude any centre (mono) signal from the reverberator.

Extremely thorough Patching is implemented, which can give you many hours of amusement trying to make the reverb brighter when the left input level is higher, or somesuch thing. Does anyone ever do this? MIDI implementation is very thorough, with all controllers received and understood, and several SysEx options. Included are the Tempo features of the PCM80: you can tap tempo in, or set it to follow MIDI clock. The PCM90 will also generate MIDI clock. Like the PCM80, S/PDIF digital input and output are available on the back panel.

The unit comes with a shiny quick-reference card, and a handy fold-out list of programs. This is repeated in the manual with longer summaries which include a description of the Adjust Knob function and a list of associated KeyWords. The manual is very comprehensive, explaining every feature, although it can be hard to find something quickly with no alphabetical index.

One useful set of programs is of Outdoor effects, handy for dialogue dubbing for TV and film. Although the unit primarily provides proper "grown-up" reverberation, there are a few special effects including ring modulation and odd multiple delays. Included are Generic presets giving the user blank page versions of effect algorithms (with no Go mode softrow or Adjust knob assignments) for creating effects from scratch. It was a nice surprise to find a re-creation of the PCM60 Room, complete with choice of four decay settings! A recent re-acquaintance with the PCM60 provided a stark contrast to this feature-packed marvel of modern technology and assignability. There are many situations where when tracking or overdubbing I would prefer to have available the quick and simple '60 instead of this potentially time-consuming beast.

The PCM90 is truly a high-end machine. It provides unequalled refinement and flexibility. It is priced slightly higher than the PCM80, probably because of its higher processing power - two Lexchip 2 processors. Compared to the 480L it looks like exceptional value. However, at double the price of the MPX1, you really have to want the best. Embedded in a track, who is going to notice the difference in quality? The way things stand I wonder if I might prefer two PCM80s and a set of algorithm/preset cards, rather than one PCM80 and one PCM90. However, we will have to wait and see what benefits future expansion cards bring.

The PCM90 is a complex piece of equipment that demands some study to get the best out of it. It offers an alternative, and dare I suggest equal to the 480L in terms of sound quality and effects. It surpasses the 480L with many of its features. However, compared to the 480L it is fiddly to use, with such extensive menus that a novice may have trouble finding a particular setting. The Go Mode feature compensates to a certain extent, but you still have to guess where a particular parameter is, and of course the one you want might only be available in Pro mode. For me, the PCM90 needs more tactile control, a bigger display, and simpler menus. If you are going to cram in so much, it is frustrating having just one adjust knob and only one parameter visible at a time. People do not work that way. There are many features included that I know I would never use, or perhaps would not have time to explore in a time-is-money situation. It is a very impressive unit, but I hope in the future to see a Lexicon unit with more of a Fisher-Price approach to design instead of the DX7s they keep producing!

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