Lexicon PCM80

It's not often that plug‑in cards merit the same attention as the equipment they plug into, but these add‑ons are capable of transforming Lexicon's PCM80 effects processor into a completely different beast, as Paul White discovers.

Lexicon's PCM80 multi‑effects unit is not yet two years old — we reviewed it back in SOS December '94 — but it has already made its name as a worthy '90s successor to Lexicon's classic PCM70. In its basic form, the PCM80 includes some fairly serious reverb algorithms, and although the number of simultaneous effects may seem limited on paper, the aural experience is never disappointing — and frequently stunning. If you own a PCM80, you can now expand its capabilites considerably, courtesy of the three new plug‑in cards under review here, two of which (the Dual FX and Pitch cards) offer new processing algorithms and presets, while the third just offers new presets.

Dual FX Algorithm Card

The Dual FX algorithm card (the blue card on the right of the main picture) extends the PCM80's flexibility by offering 25 brand‑new effect algorithms, which combine five completely new effects blocks with the five original reverb types. The algorithms must be loaded from the read‑only card whenever the machine is used — the easiest way to work is simply to switch on the machine with the card plugged in. Alternatively, you can plug the card in with the PCM80 already running, and instigate load proceedings. Once loaded, the card can be removed from the machine and the algorithms will remain available until the machine is next switched off, which means that a studio running more than one PCM80 could load them all up from a single card at the start of each day. Using the card doesn't increase the number of user presets, but it does provide five new banks of presets prefixed X.

The five available reverb blocks are exactly the same as in the basic PCM80: Concert Hall, Plate, Chamber, Inverse and Infinite. The first of the new effects blocks is Glide, comprising a stereo pair of 2‑tap gliding delays routed into four adjustable delay 'voices', each of which has its own feedback and pan parameters. The maximum delay time using a PCM80 with fully expanded RAM is a massive 42 seconds, and the pitch‑changing character of the gliding delays makes it possible to create dynamic flanging‑type effects or dramatic pitch‑shifting treatments, many of which defy simple description.

The Chorus block might seem mundane from its name, but this one sounds wonderful, and sports four separately adjustable voices, making it sound like four chorus units working at the same time. The chorus effect is crystal‑clear, with none of the noise or mushiness that afflicts many cheaper units.

Next up is M‑Band, another 4‑voice delay effect, but this time incorporating high‑ and low‑cut filters, enabling it to create repeat echoes that change in timbre as they decay. Though this isn't a new idea, it sounds exactly right, and you can get very close to setting up tape‑echo sounds or echoes that appear to fade into the far distance.

Resonant Chord Res 1 and Res 2 are derived from the classic PCM70 and PCM80 resonant effects, where precisely controlled short delays are combined with large amounts of feedback to create resonators that 'ring' at a specific musical pitch. Percussive sounds produce metallic, tuned percussion effects, whereas harmonically rich pad sounds can become quite eerie. It is possible to control the resonator pitches via MIDI, allowing percussive sounds to be processed via chordal filtering, and there are two different systems for pitch allocation, which create two distinctive effects. Res 1 assigns pitches to the four resonators chromatically — the resonators retain the pitch of the last four MIDI notes played. The result is a sustain‑like effect, as the resonators stay in their current state until a new note is played. Res 2 allocates the pitches diatonically harmonised with the scale, key and root note entered by the user. This allows a MIDI‑controlled sound to be processed in a way that creates a resonator harmony. Both versions include conventional delay, which can be up to 38 seconds for a fully‑expanded PCM80.

These five effects blocks are combined in all possible combinations with the five reverb types, hence the total of 25 different algorithms. The best way to describe the result is to pick out some of the more memorable preset types. As you'd expect, the chorus, modulation and delay effects are very clean, but what amazes me is just how much effect you can pile onto a sound without smothering it. There are rotary speaker simulations, lots of nice variations on standard treatments, and some wonderful emulations of tape flanging and tape ADT. As the basic PCM80 has a lot of nice reverbs built in, the card tends towards the less obvious, and there are many acoustic spaces well suited to post‑production work as well as to music. For example, there's a fabulous underpass/subway tunnel just crying out for a busking solo sax, and there are some frighteningly realistic rooms, which include simulations of combined close and distant miking. You also get a car park, various chambers and a symphonic string hall, which combines phasing with reverb in a very creative way.

There are numerous drum reverbs which make use of filtering combined with reverberation, a few really good plate simulations with tape pre‑delay, and various bouncing echoes. To me, the simulation of space is the most impressive factor — there are patches that create an absolutely convincing sense of distance. With some, you can even move the sound source away from you in real time! You get TV sound, telephone sound, ducking delays, composite modulation effects and a useful range of dual effects, which allow the unit to produce two quite different mono or stereo effects fed from two different aux sends. In all cases, the extensive real‑time parameter control of the PCM80 can be exploited to create patches which either respond to the sound being processed or changes sent over MIDI.

For anyone who already has a PCM80, or who is thinking of buying one, the modest cost of this card is a small price to pay when you consider the number of brand‑new, truly useful effects to which it gives you access. Not buying this card verges on the tragic!

Pitch FX Card

As it stands, the PCM80 has no conventional pitch‑shifting capability, but the Pitch card (not shown in the picture, but identical to the others in all but colour — it's mauve) changes all that, providing access to five very advanced pitch manipulation algorithms. What's most impressive is the amount of shift that can be used before the side effects of the process become significant — there's a bare minimum of that irritating modulation that makes lesser units sound permanently 'out of tune'.

First off the card is the 'Quad Hall' algorithm, which combines Hall reverb with a powerful 4‑voice pitch‑shifter. Delay times of up to 1.25 seconds per voice may be included, and each voice has variable feedback. For more shifting flexibility, the 'Dual‑Chmb' algorithm brings together the chamber reverb and a dual shifter with a vast +/‑ 3‑octave range and a precision of 1 cent. Again up to 1.25 seconds of delay may be added per voice.

As an alternative, there's 'Dual‑Plt', which substitutes a plate reverb, or 'Dual‑Inv', which uses a reverse reverb algorithm. The 'Stereo‑Chmb' option is optimised for processing stereo material, and again, the range is +/‑ 3 octaves. Finally, 'VS‑Chmb' provides on‑the‑fly, high‑quality pitch‑shifting for real‑time pitch correction or varispeed compensation. The range is limited to +55% down to ‑35.48%, with a resolution of 0.01%. MIDI control over shift is applied to some programs, and each effects block incorporates a sophisticated submixer which lets you decide how to combine the reverb and effects blocks. Facilities include stereo width, output level and filtering, as well as dry/effect balance.

The card comes with 100 factory presets organised into two banks, and within the banks, the effects are arranged into logical groups. For example, Bank X0 starts out with vocal and vocal harmony patches, before moving into guitar and instrument territory. Bank X1 strays further into X Files territory, but includes some fantastic pads and drones, pitch sequences and combination effects, as well as a set of 'clean slate' algorithms for the creation of new patches. All the patches are impressive, but some are simply stunning. I was particularly impressed by the clarity of some of the vocal thickening treatments, while other patches created spatial effects as powerful as anything I've heard from dedicated 3D sound systems. In all, you get a wide selection of presets ranging from patches that let you hand‑tune a dodgy vocal line to completely outrageous sci‑fi effects that challenge one's powers of description, and though the pitch‑shifting starts to show up side effects when you dial in huge shifts, you can move a vocal a few semitones either way without it warbling unduly. However, there is no attempt at formant correction, so the 'chipmunk on helium/Darth Vader with bronchitis' effect still rears its head if the degree of shift is excessive.

Again, this is a must‑have card for anyone into anything vaguely ambient; it's also great for everyday vocal thickening and fixing. If you have a PCM80, you just have to have it.