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LEM FX24 & FX22

Dual Multi-effects Processors By Paul White
Published March 2002

The latest dual effects processors from LEM sound better than their price might lead you to expect.

LEM MULTI-EFFECTS PROCESSORSThe LEM FX24 comes from the same stable as the GEM range of synthesizers, and is unusual as dual effects processors go in that, other than the shared front-panel controls, the two effects channels are processed quite separately and each has its own independent input and outputs. The signal path combines 40-bit processing with 20-bit input converters and 24-bit output converters. Each of the A and B effects channels has its own bank of 128 factory presets, plus 128 further user presets, and the effect types come as single, double or triple, referring to the number of simultaneous effects within the patch. The three effect categories are reverb, delay and modulation. For each effect within a preset, just three parameters are available for user editing, which means that, although the LEM FX24 may not be as flexible as some multi-effects processors, it's actually pretty easy to work with. Parameters are modified using a conventional data dial, with value read-outs on a three-digit LED display window. In normal operation, the display shows the patch number -- there's no facility for naming patches.

One nice feature of the FX24 is its internal mains power supply. On rear-panel unbalanced jacks are the single input and stereo outputs for each channel, and there's a full set of MIDI sockets. There's also a footswitch jack which could be useful in live performance.

The front panel looks a little unusual, but it's the key to the simple operation of the unit. Metering is limited to separate clip LEDs for inputs A and B, and there's a Bypass button that kills the wet portion of the signal leaving the dry portion as set via the mix parameter. A Global button gets into the global presets menu where, in addition to the patches relating to the individual channels, there are 64 more patches that store the data for pairs of channels (A and B) plus 64 more user patches. The Recall button is used to recall both regular and global presets as appropriate. Store also works for both regular and global presets.

LEM FX24 multi-effects rear panel.

The MIDI button gets the user into MIDI setup mode, where the MIDI channel can be set, as well as enabling or disabling the MIDI input and output from the unit. The SysEx capabilities of the machine can also be turned on or off here. Four status LEDs show which of the MIDI parameters are currently being addressed and pressing the MIDI button repeatedly steps through them.

The Mix button lets you set both the overall level and the wet/dry balance for either of the effects channels using the data wheel. The six Edit buttons relate to the three effects blocks within each channel, and access the edit mode for each individual effects block. The LEDs by these buttons also show which blocks are active in the current preset. A Parameter button then selects from the three variable effects parameters for that block, and the current parameter is shown by a 3 x 3 matrix of LEDs just to the left of the power switch.

As you can probably deduce from the control layout, moving from one parameter to the next often entails pressing the appropriate button several times until you get to the right one, and in the case of the Mix button, holding it down and keeping it down for a couple of seconds accesses the input level setting.

LEM FX22 Dual Multi-effects Processor

The diminutive adaptor-powered FX22 is a spin-off of the FX24 and uses the same DSP chip to provide its 40-bit effects processing, along with 20-bit input and 24-bit output converters. Again it is a dual effects unit, but this time sharing a common stereo output and with a gain trim knob by each of the two line inputs on the rear panel.

LEM FX22 multi-effects unit.

Operation is entirely preset, with 121 factory settings presented as 11 banks of 11 and accessed by means of two 11-way selector switches per channel. Other than the mixed stereo outputs, the two channels may be used quite independently or they may be cascaded to produce more complex effects using a front-panel slide switch. Each channel has Mix and Out level knobs, so operation is as simple as selecting a preset bank, choosing a variation within that bank, then setting the appropriate wet/dry mix. Peak LEDs on the front panel show if the input is overloading, otherwise its just plug and go.

The first half of the patches are reverbs and, like the LEM FX24, they're well chosen and musically satisfying. In fact, other than the lack of editability, I'd say they were of the same quality as the LEM FX24 and they cover everything from tiny rooms to cathedrals. The last couple of banks are dual effects, one reverb-plus-delay and one reverb-plus-chorus. In between is one bank of delays, a bank of chorus/flanger effects and a bank of phasers and rotary speakers. For a quick set-and-forget box, this one sounds really good, and to get two channels for this price is great, though having preset delay times is a bit of a limitation. Not only is this little box fine for demos and live work, it's also great for use with guitar preamps and could even be pressed into service for more serious recording.

The Effects

The main effect is arguably reverb, with a choice of Hall/Room and Vocal/Plate types. The adjustable parameters are reverb time, room size and pre-delay, with a maximum decay time of six seconds and a minimum of 0.6 seconds. However, depending on which reverb preset you start with, there are numerous different room styles, plus gated and reverse settings with different degrees of pre-delay. Delay is variable up to one second, with control over feedback and high-frequency filtering, while the Mod section can provide chorus, flanging, phasing, rotary speaker, tremolo or pitch-shifting (up to one octave up or down). The Mod effects have depth and rate controls, plus one other pertinent parameter depending on the effect type selected. The rotary speaker is a little different, with speed switch, acceleration rate and crossover-frequency settings.

Heard in isolation, the reverbs didn't initially seem very special at all, but once the dry sound was added, the illusion of a real space was actually surprisingly good for such an inexpensive unit. There was a real difference between the halls, cathedrals and gymnasiums provided, but what I found a real bonus was that the smaller rooms worked quite nicely too. Though not described as ambience patches, that was exactly the effect some of the smaller rooms evoked -- there was a good deal of variety, from bright tiles to an absorbent room that actually seemed to suck the life out of whatever I fed into it.

The stereo width of the reverbs was also good and, mixed in with the original at a sensible level, they sounded far more expensive than they had any right to. There are also some gated and reverse patches available and some of the gated settings were good for adding life to distorted guitars without muddling the sound. Best of all, the factory presets seem to have been created to be usable, rather than to show off all the bells and whistles of the unit, so if you don't like programming you'll probably find something in there to suit the job in hand.

The delays are pretty basic, with mono, stereo and ping pong types, but, again, nothing to complain about. Similarly, the modulation effects don't stray far from standard territory, and the rotary speaker sounds more like a chorus/flanger running at the appropriate speed, but they are all musically useful. As usual, the exception is the pitch-shifter, which works fine for detune/chorusing, but at larger pitch-shifts it produces that familiar 'bedsprings in space' effect that conspires to make everything you feed into it sound out of tune!

In the double effects section, there are some effective pairings of delay and reverb to create more obviously reflective spaces and a few useful reverb plus modulation patches that can be used to warm up guitar or pad keyboard parts. The triple effects section starts out well, with quite a few fairly subtle combinations that you might actually consider using, after which the programmer starts to create weird effects to fill up the last few slots. You know the kind of thing -- fast, yodelling modulation combined with delay and reverb. On balance, though, the number of sensible and immediately useful patches is far higher than on most other budget multi-effects boxes I've tried. Importantly, I was never aware of any significant processing noise, even though setting the input level accurately is harder without proper meters, so the claimed 102dB dynamic range would appear to be born out in practice.

Using the LEM FX24 is as straightforward as I'd anticipated from reading the manual, but you do need to start from a triple-effect preset if you want three effects at once, as there's no way to add blocks to a single effect program. To get out of edit mode, hit the Recall button and you're back in patch selection territory. The two effect engines behave entirely independently unless you use global patch mode, in which case patches are saved and recalled in pairs. This could be useful for live performance and for some studio applications, but I found it easier to consider the unit as two separate effects boxes.

On the negative side, the lack of a proper input level control and level meter was irksome, as was the inability to name patches, but when you consider that you get two very useful effect boxes in a 1U package for under £200, these shortcomings seem less serious. LEM even provide you with a stick-on label that lists all the factory patches, and which would fit nicely on a 1U blanking panel.


You can pay more than the asking price of this unit for a reverb plug-in that doesn't perform as well, so in that light the FX24 has to be seen as a bit of a bargain. The strongest point is the effectiveness of the reverbs and the variety of convincing and musically relevant environments they can conjure up, though the other effects are fine in a 'bread and butter' kind of way. Getting two independent channels is good news for those who want both reverb and multi-effects available at the same time when mixing, and though the editing facilities are very limited, it helps to keep things simple -- in any event, there are enough adjustments to bend the presets into shape, which is what this style of editing is all about. This isn't the box you'd choose if you're into creating complex power-user effects, but if you want to get the job done and you need decent quality at a budget UK price, then the LEM FX24 is a very strong contender.


  • Two independent effects engines for not much cash.
  • Overall effects quality very good, especially the reverbs.
  • Useful degree of editing via easy-to-use parameter matrix.


  • No dedicated control for setting the input level, with input metering limited to Clip LEDs.


Affordable dual mono-in/stereo-out effects with good sound quality and some editing.


FX24 £199. Price includes VAT.

LEM FX22 £129


  • FX24-quality dual effects, but for less money.
  • One-knob-per-function operation makes the FX22 a doddle to use.


  • Small rear-panel input level knobs make setting up clumsy, with metering limited to Peak LEDs.
  • Wall-wart power supply.
  • No parameter editing.
  • Effects mixed to a single stereo output pair.


One of the cheapest ways to get hold of good-sounding dual preset multi-effects.


FX22 £129. Price includes VAT.

Published March 2002