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Lexicon LXP1

There can be few effects devices around as prestigious and as desirable as those made by Lexicon. Now, with the release of the LXP1 16-bit processor, the classic Lexicon sound becomes truly affordable. David Hughes tastes the quality...

There can be few effects devices around as prestigious and as desirable as those made by Lexicon. Now, with the release of the LXP1 16-bit processor, the classic Lexicon sound becomes truly affordable. David Hughes tastes the quality...

The first fundamental axiom of the recording studio is that 'you can never have too many signal processors'. The second fundamental axiom of the recording studio is 'if at any given point in time you cannot afford a specific device, simply wait a few months and another will appear with comparable features at half the price'. It is upon these simple rules that the basic operation of the recording studio is founded.

It's true of most things in fact, from an old Ford Anglia to an XR3i. It's especially true of signal processors. Devices which were at one time the sole province of the larger commercial studios can now be obtained by just about anyone for only a modest capital outlay. The market for this type of gadget is being overrun by companies such as Alesis and Boss, who are offering processors which compare very favourably with larger, more expensive units but at a fraction of the cost.

Obviously, along with the fall in price there have to be compromises - short cuts have to be made. Typically, such devices often offer little or nothing in terms of programmability. Another avenue for cost-cutting is to use components of a lower quality, which means that an instrument may have a shorter lifetime than might be expected if components of a higher tolerance had been used.

Now, 'Lexicon' is a name which is synonymous with high quality digital audio processors. However, that elusive tag of 'quality' comes with a fairly heavy price tag. The Lexicon PCM70 has been an industry standard for about two years now, a standard which has often been beyond most smaller studios. That is, until the arrival of the Lexicon LXP1.

What's so special about the LXP1 ?

Essentially, it is a stereo preset/programmable 16-bit audio processor which offers 16 different types of effects and a state of the art MIDI specification. When you consider that the asking price for the PCM70 is around £2,000, it doesn't take a genius to realise that Lexicon must have made a few short cuts to seriously reduce the asking price of the LXP1 to a fraction under £400. The question is, where have they made them and do you, the end user, suffer for it?


Physically, the LXP1 box is 1U high and of half-rack width, and as such could easily be mistaken for one of the aforementioned Alesis units. The front panel does, at first, appear a trifle sparse. There are three rotary pots to the left of the unit and these control input level, output level and the ratio of processed to unprocessed sound at the input. There are also two LEDs which give an indication of the magnitude of the input signal, the green LED indicating the presence of a signal, the red indicating that you're overloading the unit.

In the centre of the front panel is the effects select switch and to the right of this are two parameter pots, labelled Decay and Delay, whose function is dependant upon which effects program you're using.

There is one last feature and that is a small pushbutton marked 'MIDI' which sits in the top right-hand corner of the unit. It is this switch which allows you to access the deeper, more complex functions of the unit - but I'll save them for later. To the rear of the unit are the stereo audio inputs and outputs (all ¼" jack connectors), MIDI In and MIDI Thru, a 'defeat' input socket for connection of an external footswitch, and finally a 9 volt power socket. Sadly, there is no On/Off switch - an obvious shortcut.


After quickly scanning through the user manual - which is excellent - my first impression was that the LXP1 is very flexible. It has three possible modes of operation: the first is simply as a stand-alone audio processor; the second as a real-time, performance orientated signal processor; and thirdly, as part of a larger, studio orientated audio processor. In the latter mode the LXP1 operates along similar lines to the Oberheim Matrix 1000 and Roland MT32, in that the ability to edit parameters from the front panel is very limited. However, in keeping with their PCM70, Lexicon have thoughtfully taken advantage of the delights of MIDI System Exclusive messages and provided a processor that can be controlled much more extensively via MIDI.

In its most basic mode, the LXP1 can be used simply as a preset device. It offers 16 effects types directly selectable from the front panel, and these divide themselves roughly into simple emulations of various sizes of auditoria - for example 'Small Room', 'Large Hall'; reverberation effects such as 'gated reverb; and finally, delay-type effects. In general, I found most of the presets immediately useful. The frequency response of the processor is very good and the processed sounds were always full of energy in the high frequency ranges. The 'Hall' type effects are convincing and add a healthy degree of colouration. The 'Small Rooms' are quite subtle and require careful listening to actually hear the techniques at work.

As you might expect, the Decay control sets the reverb decay time and the Delay pot sets the amount of pre-delay between the start of the signal and the onset of the first reverberations. The range of pre-delay is selectable between 0 and 246 milliseconds, though you may select only one of 16 available settings for this parameter. This range of values is quite acceptable in normal use, though at first I wasn't truly happy with this compromise.

The 'Plate' reverb effects are useful and are best applied to short, percussive voices. Two types of 'Plate' reverb are provided, 'dark' and 'bright'. The 'Delay' type effects are good fun and can add a lot to a tired mix. I managed to create a number of extreme flanging effects as well as a more subtle delays ranging from simple chorus sounds through to audible echoes. At this point I was quite impressed with the LXP1, although I would have liked to see some means of preserving simple edits at least. A finer resolution on the control pots would be an advantage, too. But I must say that, so far, the LXP1 gets the 'thumbs up'.


To operate the LXP1 in its second mode, you really need some kind of MIDI controller, such as a keyboard or MIDI-fied guitar. When you edit the presets from the front panel, each of the settings is lost if you select another preset or switch the power off. The solution Lexicon have adopted is to use MIDI Program Change messages to store and recall up to 128 user-definable programs.

To do this, you simply connect the MIDI Out of any MIDI-equipped synthesizer to the MIDI In of the LXP1 using a standard MIDI cable, and then assign the LXP1 a MIDI channel number on your master controller. Then, while holding down the aforementioned MIDI button on the front of the LXP1, you need to transmit a complete MIDI message to the unit. This can be any message that has the channel number encoded in the status byte of the MIDI message - a MIDI Note-On/Note-Off sequence or a Program Change command, for instance. The LXP1 is now set up to respond only to information on the specified MIDI channel.

Having set the MIDI channel of the LXP1 to the required channel on your controller, you can perform something a little more constructive - such as saving edited data from the front panel. This is simplicity itself and involves selecting a suitable Program number from the 128 available, pushing the MIDI button on the LXP1 and, hey presto!, the effects data is saved. Things get a trifle more complicated if your MIDI controlling device doesn't address the 128 locations in a straightforward manner. For instance, attempting to do this from the front panel of my Yamaha DX5 - which addresses its patch data in eight blocks of eight - meant that I had to do a wee bit of quick arithmetic to select the correct Program location. Strangely, the positions of the Input, Mix and Output Level pots are not stored along with the program data, which I would have thought very important, particularly with respect to the Mix parameter.

One of the features of the PCM70 which made it so marketable was the inclusion of what Lexicon term 'Dynamic MIDI'. This is a performance feature which lets you map a MIDI controller (eg. Pitch Bend wheel, Sustain pedal, etc) on your master instrument to a parameter within the PCM70. The good news is that Lexicon have extended a limited version of this feature to the LXP1.

To create a Dynamic MIDI patch you must follow a fairly involved procedure, which the manual explains in quite some detail but which I felt was a little on the fiddly side to attempt during a live performance. However, the results are worth the effort and it is possible to produce some interesting effects. For instance, extending the decay curve of a reverberation effect with the Modulation wheel of a synth is quite a revelation.

Another plus is the Voice Defeat switch, which mutes the incoming audio signal leaving only the processed signal at the output. An effect which proved to be very effective - if you'll pardon the awful pun - when used with the reverb treatments. Furthermore, the muting appears to be done electronically. There was no audible 'thump' on the output as a result of pressing the footswitch, which is often a limiting factor in less expensive devices.

What makes the LXP1 really special is its MIDI implementation, which is comprehensive to say the least. There are a number of features that are not accessible from the front panel but are available via the MIDI interface. In fact, most of the limitations I have discussed above do not apply if you can access the relevant parameters via MIDI.

A large proportion of the user manual is given over to descriptions of the MIDI System Exclusive format, so we should be seeing software-based editor packages appearing for the LXP1 in the not too distant future. Lexicon will shortly be introducing an optional controller of their own -the MRC - which can be used to edit every parameter on the device (of which there are an awful lot) and, hopefully, provide a more musically useful user interface. The documentation also specifies that the MRC may be used to edit parameters on the PCM70 as well as any Yamaha 6 Operator FM synth, which is definitely not a bad thing!



Frequency Response 20Hz-15kHz (effect)
20Hz-20kHz (direct)
A/D Conversion 16-bits
Dynamic Range 85dB typical
Input Impedance 50Kohms (stereo)
25Kohms (mono)
Output Impedance 600 ohms
Power 9 volt AC adaptor
Connectors Stereo In/Out (jacks), Defeat footswitch, MIDI In, Thru
Programs 16 adjustable presets - Small, Medium, Large Rooms; Halls; Plates; Inverse Room; Gate; Chorus; Delays
Controls Program Select, Input Level, Output Level, Mix, Decay Time, Pre Delay Time, MIDI On/Off
MIDI Control Editing of parameters using System Exclusive commands; Program Change; Dynamic MIDI parameter control

To conclude then, the LXP1 appears to be a software solution to a hardware problem. The number of parameters that are available from the front panel is minimal, but that doesn't prevent the LXP1 from producing some great sounding effects. However, there are a number of features that devalue what I would otherwise regard as a really excellent unit. The lack of an On/Off switch, for example, which means that I have to play my 'favourite' pastime of 'hunt-the-power-pack' at the end of every session!

The audio side of the LXP1 is superb. The unit is very easy to use, although it must be said that as a preset-only device it is flawed. Even so, £399 will seem a small price to pay to some users for the classic Lexicon 'sound'.

If you want to take full advantage of this instrument then I think you must be prepared to reserve some of your funds for a software-based System Exclusive editor. The hardware controller which Lexicon intend releasing as an optional extra will be a good buy for those of you who don't already have a computer-based system - plus you get the added bonus of a Yamaha DX controller/editor thrown in for good measure! It would be wrong - as well as unfair - to say that the LXP1 is a cut-down version of the PCM70. Indeed, it is a first-rate instrument which I feel sure will be very, very popular.

Price £399 inc VAT.

Contact Stirling Audio Systems Ltd. (Contact Details)

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Previous Article in this issue

The Shape of Things to Come

Next article in this issue

Octapad II

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 - Oct 1988

Gear in this article:

Studio FX > Lexicon > LXP1

Gear Tags:

Digital FX

Review by David Hughes

Previous article in this issue:

> The Shape of Things to Come

Next article in this issue:

> Octapad II

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