The PCM60 is the latest in a long line of time-based digital audio processors from the American company, Lexicon. Their model 224 Digital Reverb is amongst the top three in its class and can be found alongside the likes of AMS and Quantec in most top class professional recording studios around the world.

The technology of the 224, having proven itself, has now been simplified and incorporated into a much more affordable reverb unit aimed at the smaller studio and live performer. The flexibility of features and degree of control of the reverberation effect have been sacrificed somewhat in order to produce a device that sells for around £1600, but rest assured that no compromises have been made in terms of the sound quality, which remains first class.

Presentation

The unit is presented in the now familiar 1U high, 19" rack-mounting metal case with controls mounted on the pleasant-looking mauve and black front panel. Control layout and function is simple to follow making operation an extremely easy task.

The PCM60 offers the user two basic reverberation programs - 'Room' and 'Plate' - each with four 'Size' and 'Reverb Time' variations. It must, however, be pointed out that the PCM60 is in no way programmable, the user being offered only a selection of preset reverberation effects. This may or may not be viewed as a limitation of the machine, depending on your requirements, for the preset reverberation treatments provided will certainly satisfy the needs of the majority of potential users. Don't forget, your spring reverb is non-programmable too!

Controls

The device can be operated at two levels: +4dB or —20dB, and a peak reading five segment headroom indicator and level control are provided for obtaining the optimum input signal levels. Sensitivity select pushbuttons located on the rear panel allow the choice of input/output operating levels to match as wide a range of equipment as possible. Overall output level is panel knob adjacent to the 'Mix' contro which varies between direct (dry) and treated (wet) signals. When the unit is connected to a mixer's effects loop, this control is best left set fully on 'wet'.

A bypass function is also provided which can be selected directly using the front panel pushbutton or remotely via a footswitch connected to the rear panel's bypass socket which overrides the front-panel control.

Selection of reverberation effects is from the row of 12 pushbuttons that take up the remainder of the front panel, and each one has a colour-coded LED statue indicator.

Of the two program modes, 'Plate' and 'Room', the densest effects are obtained on the Plate setting. With this button engaged you choose from the four 'Size' presets (ranging from 'small' to 'large'), and four 'Reverb Time' presets ('short' to 'long') to create the required reverberation treatment. Reverberation times of 0.3 to 3.8 seconds and 0.2 to 4.5 seconds are possible in the 'Room' and 'Plate' modes respectively, dependent upon the selected 'Size' button. This latter parameter corresponds to the pre-delay aspect of natural reverberation which is responsible for the apparent size of any acoustic environment, hence the control's name. In 'Room' mode, pre-delay times of 6, 9, 16 and 37 milliseconds are available, whilst 'Plate' mode offers variations of 1, 2, 7 and 46 ms.

Using a combination of the four 'Size' and four'Reverb Time' buttons, 16 preset reverb effects are possible in both program modes, giving a total of 32 different effects in all. These range from a very 'tight' sounding metallic box effect to a large 'open' concert hall, with all the more familiar acoustic environments in between.

To further aid the simulation of natural-sounding rooms, 'Bass' and 'Treble' frequency contouring controls are provided which are intended to give the user some means of varying the sound absorption qualities of the synthetic environments. For example, a room with very hard, reflective surfaces will create a much brighter sound than one whose surfaces are covered in soft, sound absorbent materials.

The 'Bass' control has the effect of increasing or decreasing the low frequency reverb time of signals below 800Hz, whilst the 'Treble' control increases or decreases the reverb time decay of signals above 800Hz and adds a gentle roll-off above 2kHz as well. The exact functioning of each contour control is dependent on the setting of the program mode controls, but they are an extremely useful inclusion and go a long way towards expanding the reverb variations possible on the Lexicon PCM60.

Connections

All input and output connections are made via standard ¼" jack sockets at the rear. Input is for balanced or unbalanced operation, whilst two unbalanced 600 ohm output sockets enable the PCM60 to be operated in stereo mode - by far the best way if you want to achieve the most realistic and effective reverb treatments.

The device can be patched into the effects send/return loop of a mixing desk, but the greatest flexibility is obtained by returning the left and right outputs to two separate input channels on the desk allowing further equalisation of the reverb signals. For live performance situations, the unit can be mated quite happily with a variety of guitar/keyboard amps placing it 'in-line' with instrument and amplifier.

The final connectors are the 'Effects Send' and 'Return' sockets. These tap off the input signal before it is processed by the reverb circuitry and allow it to be sent off to any external processor connected via these sockets for further modification. You could, for example, connect a digital delay in order to increase the amount of reverb pre-delay effect, which would help to vary the type of room environments that can be simulated on the unit.

In the same way, a graphic EQ would enable greater control to be made over the frequency content of the reverberated signals. A good facility which adds considerably to the versatility of the unit.

Sound Quality

With a reverberant signal frequency response of 20Hz to 10kHz and a dynamic range of 80dB the quality of effect is extremely high indeed. Subjectively, the effects obtained had a bright, up-front character to them in the studio. The only reservation is with the very low frequency signal reproduction. The digital drum machines used for testing purposes managed to elicit some distortion on accented snare and bass drum sounds, mostly on the larger 'Size' settings it appeared, but it was something you could easily live with.

The noise performance was highly commendable, the unit being almost transparent when patched into the system.

Impressions

The studio used to test this Lexicon device happened to own a Yamaha R1000 digital reverb, and A/B comparisons between the two were enough to justify the Lexicon's asking price in my mind. It is a true digital reverb that produces a totally 'realistic' end result that can enhance any recording it is used on. The Yamaha and Lexicon, on paper, share some common specifications, but these mean nothing in reality. You've only got to listen to the two to discover that!

In comparison with the MXR 01a unit (its nearest rival, I guess), this Lexicon reverb is rather limited. The maximum reverb time of 4.5 seconds reduces its creative applications somewhat if you're a fan of Trevor Horn-style productions; a 10 second or so decay would have been much better. I would also have liked a longer pre-delay setting than the maximum 46 milliseconds currently offered by the manufacturers.

When all is said and done, you're basically left with the same old question: preset or variable? Both approaches have their merits on a device such as this. There's a lot to be said, for example, for a unit that provides a very good selection of usable reverb effects which are instantly obtainable in the studio or on stage, as with the PCM60.

However, with the provision of user-programmable memories that can be called up just as quickly as any preset, you can retain flexibility without sacrificing anything. The choice is yours. If you're looking for a high quality, clean reverb sound suited to general recording applications, then the Lexicon PCM60 should provide all you need. If you want more, look elsewhere.

The Lexicon PCM60 retails for £1610 inc VAT.

Details from Scenic Sounds Equipment, (Contact Details).