I have to admit to a little bias on my part. I would have bought an LXP1 when they first came out if it wasn't for the user interface: one major knob and no display to speak of (a single LED!?). The LXP5 which followed offered a different assortment of effects, but had the same appearance and interface. It must be said, however, that the low price and high sound quality of the two units more than makes up for the user interface, especially since the very full MIDI implementation facilitates use with a computer.

The LXP15 moves a step closer towards the more traditional Lexicon role: sophisticated and smooth multi-effects combined with very versatile control options. For about the price of an LXP1 and LXP5 together, it adds a backlit red LCD display with two lines of 40 characters, five 'soft' keys and a rotary parameter adjuster knob — all in a very deep (almost 14" from front to back!) 1U high 19" rack-mount box. Inside, a large PCB contains lots of hi-tech electronics, including two Z80 microprocessors, a special 84-pin custom 'Lexichip' DSP and a Burr-Brown PCM54 DAC, as well as a power supply — no mains adapter needed here!

Lexicon are famous for the quality of their effects, and the LXP15 lives up to the reputation. In these days where almost everything comes with built-in digital reverb, it comes as quite a surprise to hear 'real' reverb again. Instead of the mushy smearing of the ends of notes, some of the LXP15's 128 factory preset programs take me right back to the college circuit: impossibly square rooms with gloss painted concrete walls, floor and ceiling, huge support beams parallel to the stage and no attempt at acoustic treatment except the crowd. Playing in a venue like that is a physical experience — the sound comes back and hits you. The LXP15 has those echoes and early reflections exactly right, as well as a very nice line in reverberation proper, and more! The conversion resolution is 16-bit and the sample rate is 31.25kHz, giving an 85dB dynamic range and 20Hz to 15kHz frequency response for the wet signal: fine for all but the most exacting of 44.1 kHz enthusiasts.

There are five sophisticated algorithms, each combining several effects in a fixed architecture, so you can't string effects together yourself. But the algorithms seem to be designed for versatility; you begin to wonder if you actually need total flexibility in assembling your own delays, reverbs and pitch shifters... All of the algorithms have delay and pan sections, and all except the chorus have reverb, but this does not mean that you can't combine chorus and reverb-type effects because the overlap between the algorithms is quite wide — for example, you can use a slight pitch shift to create chorusing, and the reverb can be used with pitch shift. The stereo inputs are summed for initial processing, and the final panning provides the stereo outputs.

The five algorithms are: Delay/Reverb, Pitch/Delay, Gated Reverb, Plate Reverb and Chorus Delay. The first part of the name indicates the specialism that the algorithm is optimised for. Thus the Delay/Reverb algorithm has a real-time sweepable 'glide' delay which opens up all sorts of possibilities for the creative use of time modulation, whilst the Pitch/Delay's Pitch Shifter can be used to produce chorus, but by adding feedback from the associated delay elements you can create rising or falling repeats.

The Lexicon name is almost synonymous with the creative use of MIDI control. The LXP15 allows the use of all the MIDI Controllers, as well as Note events, Velocity, After Touch and Pitch Bend. You can patch any four of these to any of the effect parameters, which allows for interesting tricks like setting the pitch shift range using velocity, or varying LFO speed with the sustain pedal. More conventional user controllers like footpedals and footswitches provide five more options, whilst the internal LFO and Envelope Follower provide cyclic or dynamic modulation options. It is also possible to control one parameter globally, so you can assign a footpedal to a common parameter like output level or effect mix.

You also have a wide choice of parameters to modulate: for example, the Pitch/Delay algorithm has 22 separate parameters. Unlike most multi-effects units, the LXP15 solves the problem of editing lots of parameters by providing a rotary switch which can quickly select any of the five parameter 'pages', with up to five parameters per page. The soft keys under the parameters then select the value to be edited with the large 'adjust' rotary control knob (which sometimes needs rather too many turns to make any significant changes to values). This way of accessing parameters for editing works very well, since you can go to an edit page very quickly and tweak a parameter without any need for convoluted cursor or menu selections: 10/10!

The LXP15 is deceptive, since much of its power lies in its extensive modulation facilities, which let you make the most of the very flexible algorithms. The presets illustrate this very well by avoiding many of the standard effects cliches and substituting more off-the-wall treatments, such as a reverb which changes to a stereo echo as you increase the input level. This 'LXP5 with display and knobs' sounds wonderful, wonderfully real or even wonderfully weird if you want, and it repays investigative programming or wild experimentation by producing expressive personal effects. It reminds me very much of the way that Emu's Proteus hides a wealth of synthesis power behind a simple front panel; perhaps the LXP15 is the 'Proteus' of the effects world! The more I used it, the more I found I could do with it — and the more I wanted it!

Further information

£938.83 inc VAT.

Stirling Audio, (Contact Details).