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Lexicon LXP5 Multi-Effects Processor

Following the release of their acclaimed 'budget' LXP1 reverb, Lexicon have extended their presence in the affordable digital effects market with the LXP5 multi-effects unit. Dave Lockwood feels the quality.

The Lexicon LXP5 is a multi-effects companion to the highly regarded LXP1 reverb, expanding the Lexicon 'budget range' of high performance, easy to operate and affordable units. What might appear on the surface to be an entirely preset device, offering four basic families of effects, in fact proves to be a tool of enormous creative potential, with multi-level access to its inner workings, allowing the adventurous user sophisticated editing and realtime MIDI control. Like the LXP1, the LXP5 is housed in a half-rack case and runs from an external power adaptor. It has just six controls on the front panel, plus an intriguingly named 'Learn' switch. A variable input level permits use with the widest possible range of input signals, from instrument level right up to the full +4dBu 'pro' standard.

The rear panel provides four audio connections via unbalanced ¼" jacks, with the now common automatic switching arrangement which allows a single input to feed both channels. Also, if only one output jack is used, then the left and right output signals are summed to mono. A fifth jack allows connection of an optional footswitch, which can be either a latching on/off or the momentary push-on/push-off type, depending,on which aspect of the LXP5 you wish to control with it.

The rear panel also includes MIDI In, Out and Thru sockets, which are the key to much of the LXP5's power - the use of MIDI gives you a degree of control and programmability with the LXP5 that sets it apart from other budget units. Having said that, MIDI control is not essential - the LXP5 has an excellent two-tier operating system that allows an 'average' user to access the most basic functions at first sight, without recourse to a manual, but also provides very comprehensive control at a deeper level, as we shall see.


The LXP5 can produce up to five effects simultaneously, and a total of 186 effects programs can be selected from the front panel - 64 preset and 128 user programs. Programs are selected with two 16-position rotary switches. The Function switch selects a bank, and the Select switch then accesses one of the programs within that bank. The preset programs are divided into four banks (Pitch, Delay, Chorus and Multi) and there are eight user banks. Within each program, a third rotary switch - Adjust - can be used to modify the most important effect parameter, providing a very convenient and immediate means of controlling an effect in real time.

Obviously, when a program is first selected the physical position of the Adjust switch will not necessarily reflect the actual value of the parameter to which it is assigned. To warn you of this, the green LED adjacent to the Learn button flashes, and then shines steadily when the switch has been rotated to the correct position. If the switch is then further rotated to edit any parameter, the LED shows red. Naturally, this whole system is much easier to implement with a pot with discrete steps than it would be with a continuously variable control, hence the detents.

Scanning through the preset programs, one of the first things to strike me was that it wasn't always obvious which parameters were being controlled by Adjust, particularly on the pitch change effects. There were some where it set an LFO modulation rate, and others where it was obviously setting a semitone transposition interval, but on the weirder programs such as the Glissando and Tunnelling effects, it is hard to tell by ear just what it is doing.

Six out of the 16 preset pitch change programs are simply different preset semitone intervals, with two micro tune programs for creating detune effects. As with all budget pitch-shifters, the smaller degrees of shift sound fine, but anything more than about a major third up or down starts to get a bit wobbly. Critical listening to the pure shifted signal reveals the expected glitching rendered as a gentle and slightly eccentric vibrato, but with a pleasing absence of the usual nasal colouration. Frankly, this is a rather unfair test of what is after all a budget-priced unit - how many people do you know who use their pitch shifter in this up-front manner - and in the context of a mix I can say that the detune effects do sound distinctly classy. The audio bandwidth of the processed signal is a worthy 15kHz (dry signal 20kHz), but that is not spectacular by present day standards, so perhaps the perceived classiness is something to do with the legendary 'Lexicon Sound'.

The 16 preset Delay programs, many of them involving considerable stereo interest, are particularly clean and cover the full range from straightforward repeat, stereo slapback and imaging, to distinctly epic 'New Age' diffuse ambience. Many of the echo programs involve multiple delays, with separate repeats on either side of the stereo image; a superb effect which can create a massive sound on solo instruments, particularly guitar.

The third bank of preset programs is called Chorus, although it actually includes a wider range of effects than the name implies. In addition to standard chorusing and all its variants (including flanging), there are several 'imaging' and 'resonance' programs, some of which are very reminiscent of PCM70 effects. However, if you are seeking a thick, warm analogue-style 'churning' effect you will be disappointed, for these programs are characterised by a clean and transparent quality - which is, of course, an asset in all but this one application. A range of static notch-filtered effects and some rather subtle programs, whose principal impression is one of stereo animation, complete this bank.

The final bank of 16 presets is called Multi, although many of the programs in the other banks seem to include multiple elements too. The Multi programs range from the divine - some superb long reverbs, with all sorts of interesting stuff going on in the decay - to the simply daft, such as pitch shift plus feedback effects that simply spiral up or down uncontrollably.

The first 64 user slots hold duplicates of the main presets, with locations 64 to 128 offering an entirely new set of effects. Apart from some totally off-the-wall stuff, I think it is these programs that show the LXP5 at its best, with some adventurous programming producing some truly stunning and surprising treatments.

Many of these higher numbered programs are also notable for being controllable in real time via MIDI, with various parameters reacting to both Controller and Note information. Some also respond to MIDI clocks, synchronising delay time to tempo for instance. These programs display the true power of the LXP5, and hint at the potential for producing spectacular or very precisely tailored effects through editing. So just how do you go about editing or creating a program of your own on a unit that doesn't have an LCD display?


This is where the 'Learn' function comes into play. After selecting the program you wish to edit (Function switch, then Select), you must press and hold the Learn button whilst switching the Function selector to Edit A, Edit B or Edit C, according to which parameters you wish to have access to, and then release it. The Select switch now becomes a parameter selector, and Adjust becomes a data entry dial.

How do you know which parameter you are altering? With great difficulty, as there is no visual feedback on this aspect of the LXP5's operation. Unless you have a phenomenal memory, and can remember where to find all the parameters, you will spend most of your editing time with your nose stuck in the manual - I certainly did. All the information you need is there, and it's well laid out in clear tables, but I won't pretend it is fun. However, you can at least get at every function from the front panel, including the choice of basic algorithm on which the effects are based.

The LXP5 bases its effects programs on either of two configurations: Pitch/Delay, which includes delay, pitch shifter, EQ and ambience; or Delay/Reverb, which incorporates delay, EQ and reverb. It is important to know which algorithm the effect you are creating or editing is built on in order to avoid trying to edit a parameter that is not available.

Delay time is variable via both Coarse and Fine parameters, offering very precise control. The maximum time for the mono delay option (Delay 1) is 1040ms (just over a second), and bandwidth remains independent of delay time. The more complex stereo delays (Delay 2 and Delay 3) will extend up to 325ms each. Maximum pitch shift is from two octaves down to one octave up, variable in semitone steps in Coarse adjust mode, and in steps of a few cents in Fine adjust mode. In practice, I found the steps in Fine resolution just a little too large to control the most subtle detuning effects.


The degree of variation in the reverb effect depends on which algorithm is chosen. Reverb decay time can be varied from 0.5s to 12s in the Pitch/Delay algorithm, and from 0.5s to infinity in the Delay/Reverb algorithm. High Frequency and Low Frequency decay times can be set independently, along with a Size parameter - variable from 8 to 53.5 metres, and representing the cubic dimension of the hypothetical reverb space - to determine the fundamental reverb characteristics. Diffusion, expressed as a percentage value, seems to control the degree to which sounds retain their attack in the reverb field; high diffusion gives a softer, smoother quality, with no clearly defined early reflection set.

The LXP5's EQ section consists of one high pass and one low pass filter. The cutoff frequency of the low pass filter is variable from full range down to 320Hz, and the high pass from full range up to 1.35kHz. On the whole, these equalisation facilities are hardly remarkable, but are fine for the intended purpose of rolling off high frequencies from successive delays, taking the 'mud' out of long reverbs, and all those other useful little tasks that would tie up an external EQ device if the facility were not built in.

Overall input, output and mix levels are set with three dedicated front panel knobs, but you can also set level parameters within a program, to control the internal balance of effects, and also their panning.

The final aspect of an effects program that you might like to look at before storing it is that of assigning a parameter to the Adjust control. You will recall that when a preset is dialled up, you are able to vary one of the parameters immediately with the Adjust control, without going through any edit modes, and it is this facility more than anything that gives the LXP5 its simplicity and immediacy of operation.


Although you can access all the functions of the LXP5 from its front panel, you can also control it via MIDI, either from a keyboard or from a dedicated control device such as Lexicon's own MRC MIDI Remote Controller.

To take advantage of the MIDI functions you must first define the receiving channel of the LXP5. This can be very simply accomplished by sending it any complete MIDI message, except a Program Change, whilst holding down the Learn switch. On releasing Learn, the receiving channel is matched to that of the sending device, and effects programs can then be recalled simply by sending Program Change messages on the appropriate MIDI channel. However, any subsequent use of the Adjust control seems to cause the unit to revert to the program selected on the front panel. This is a little confusing, and I'm not really sure if it's supposed to happen or not - if it is, then I don't think it should be! You can also use MIDI Program Change messages to select memory locations for storing an edit, by sending the message whilst Learn is activated.

All pretty basic stuff so far, but the real power of MIDI control lies in the potential for real-time manipulation of program parameters with MIDI controllers - what Lexicon have referred to since PCM70 days as 'Dynamic MIDI'. Any controller can be assigned, or 'patched' in LXP5 terminology, to any parameter - in fact, you can have up to four parameters at once allocated to the same controller. There are three types of patching available: General Purpose Patches, where a controller is assigned to a parameter within a particular program; Adjust Knob Patches, where parameters are assigned for front panel control, as described; Global Patches, where controller assignments to a particular parameter apply irrespective of program selection.

Up to four General Purpose Patches can be stored as part of an effects program. Due to the LXP5's lack of display, programming these assignments involves a good deal of poring over the manual, but fortunately a short cut to creating the patches exists, in the form of the MIDI Learn method. This involves first putting the LXP5 in edit mode, and making sure that the required real-time control parameter is already assigned within the program to the Adjust knob. Then, whilst activating Learn mode, simply send a controller message from the controller you wish to assign, and it is automatically patched in. If you want a Mod Wheel assignment, say, just move the Mod Wheel slightly - it's as simple as that. Although this method limits you to one General Purpose Patch at a time, I was quite happy to settle for that in most instances for the sake of speed and relative simplicity.

Two further parameters are available to determine how the incoming control data is mapped to the value of the parameter to which it is assigned: Scale Factor and Threshold value. These interact to create an offset from the transmitted value of the control source, thus determining the sensitivity and range of control available. Threshold lets you define which part of the available range you wish to work with, whilst Scale Factor sets how large a parameter change you get for a given controller movement. A high Scale Factor enables a limited range controller to access the full range of possible values, whilst a low Scale Factor will give very fine control over a limited range.

You are not limited to using only 'normal' controllers as sources, such as Pitch Bend, Mod Wheel, Foot Controller, Data Entry etc - Last Note, Highest Note, Lowest Note, MIDI Clock, Channel Pressure, and all Continuous Controllers can be used to control patches. Where switch controllers are used, as opposed to the continuous variety, they can be employed to switch between two preset values (giving perhaps two different delay times, or reverb balances) rather than just on or off.


Talking of switches, the LXP5's rear panel footswitch jack is assignable to control one of four different functions: Bypass; Defeat Input, which allows effects to decay naturally; Defeat Output, which shuts down the 'wet' output immediately; Program Select. This fourth option allows you to step through the effects programs sequentially - first the User registers, then the Presets, Bypass, the Edit Buffer, then back round to the start of the User set again. Unfortunately, this stepping only goes one way, and with so many memory locations to step through, you wouldn't catch me using this as my effects program selection method on stage!

I mentioned the Lexicon MRC earlier, as a source of MIDI control for the LXP5, and indeed one was supplied along with the review unit. The potential of the MRC has been more than adequately covered by Martin Russ's article in the March 1989 issue of Sound On Sound, and therefore I hardly need to say what a transformation the presence of this device makes to programming the LXP5 (or the LXP1 or PCM70 for that matter). The MRC's decent sized LCD window, four simultaneously active, assignable data entry sliders, and numeric keypad remove all the uncertainty and manual-scouring from the editing process and actually encourage experimentation. They also make it much more fun! However, I do think Lexicon should have made it possible to load programs back from the LXP5 into the MRC for further editing. This is what one at first assumes to be one of the MRC's main functions, yet there is seemingly no way it can be done; programs can only be created in the MRC and downloaded to the receiving devices.


The beauty of the LXP5 is that you can work with it at any level you choose. If you want nothing more than a simple preset machine which responds to MIDI Program Changes, but which nevertheless offers high quality effects, then it is ideal. If you want to exploit the power of Dynamic MIDI for real-time control and expressive performance effects, then those facilities are available too. If you are a System Exclusive genius, then the sky's the limit.

It is easy to forget that the LXP5 costs under £450, and common sense dictates that there must have been some compromises made somewhere, but in the final analysis it is sound quality that counts, and this unit will win plenty of admirers on that score. Individually the effects all stand up to scrutiny, but it is in combination that they really shine. Bearing in mind the price, one could consider reserving an LXP5 for really special or unusual treatments rather than employing it for basic effects that can be covered by other units.

This is a cleverly conceived product, in that it is both a highly effective device in its own right and a building block in an expanding system. I will forgo the usual eulogies about the famous 'Lexicon Sound' - I am not sure that they are all that relevant to non-reverb effects - but will conclude by stating that, on a power-for-price basis, it is difficult to see a serious competitor for the LXP5, and indeed that the combined power of an LXP1, LXP5 and MRC system would be hard to beat at any price.


LXP5 £438.15; MRC £357.65; LXP1 £438.15 inc VAT.

Stirling Audio, (Contact Details).

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Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Dec 1989

Donated & scanned by: Mike Gorman

Gear in this article:

Studio FX > Lexicon > LXP5

Gear Tags:

Digital FX

Review by Dave Lockwood

Previous article in this issue:

> Recording Techniques

Next article in this issue:

> Korg T2

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