You are here

Lexicon MX400/400XL

Multi-Effects Processor By John Walden
Published November 2006

Lexicon MX400Photo: Mike Cameron

Lexicon's MX200 offered the innovative ability to integrate with a sequencer host just like an effects plug-in. The updated MX400 goes one better — it does all that, but with dual effects-processing engines too.

Regular SOS readers may recall Paul White's review of the Lexicon MX200 multi-effects processor from the November 2005 issue. This MX200 provides access to a range of excellent-quality Lexicon effects — including some very respectable versions of their famous reverb algorithms — at a very attractive price point. However, the key trick up the MX200's sleeve was its USB connectivity and, via the supplied MX-Edit software, its ability to integrate into a suitable sequencer host like an effects plug-in.

Lexicon now have two new models in the MX range; the MX400 and the MX400XL, the latter reviewed here. As with the MX200, the new units can use USB or standard MIDI I/O to send patch and control data to and from a suitable computer, while all the audio data must be passed via the analogue I/O or the included S/PDIF I/O (as Paul's review commented, it's a shame that the audio can't also be passed via USB, as this would have allowed a very neat cabling arrangement). However, the MX400 models can be thought of as the MX200's bigger siblings, as they offer four-channel operation. This can be configured in a number of ways, but the most obvious difference between the 400 and the 200 is that the 400 can operate as a surround processor (LR front and LR rear) or as two independent stereo processors (A and B). As with the MX200, each processor actually features two effects engines, so, for example, while Processor A might be dedicated to a high-quality reverb (using both effects engines), Processor B might be used to chain together a delay (engine one) and a chorus (engine two).

Aside from featuring different types of analogue connectors (the MX400 has balanced/unbalanced TRS jacks, while the MX400XL uses balanced XLRs), the two models offer identical processing options. Given that audio has to pass between the computer and the MX400s via analogue or S/PDIF, to get the most out of one of these units users will probably need an audio interface that features a six-in/six-out configuration. This would allow enough ins and outs to satisfy the MX400 and still allow stereo recording and stereo monitoring.

Effect Algorithms

  • Reverbs

Small Hall; Large Hall; Surround Hall; Small Plate; Large Plate; Room; Chamber; Gated Reverb; Reverse Reverb; Vocal Hall; Vocal Plate; Drum Hall; Drum Plate; Ambience; Studio; Arena; Spring

  • Delays

Studio Delay; Digital Delay; Tape Delay; Pong Delay; Mod Delay; Reverse Delay; 2-tap Delay

  • Dbx Dynamics

Compressor; De-esser

  • Other Effects

Chorus; Flanger; Phaser; Tremolo/Pan; Rotary; Vibrato; Pitch Shift; Detune

Leading From The Front

While the MX400 is most easily thought of as an 'MX200 x 2', the increased processing power and more flexible routing possibilities have required some changes to the front-panel layout. The left-hand side of the panel features input-level controls for input pairs A and B, and these include similar four-LED metering to the MX200. The layout of the right-hand side of the panel also mimics the MX200, featuring a two-digit, numbers-only display and a large rotary knob for program selection. The biggest difference is in the centre, which now features fewer dedicated controls but does include a clear four-line display for editing purposes. As with most multi-effects processors, the functions of the various controls vary depending upon what options are shown on the display. A little bit of page-scrolling is required to operate the MX400 from the front panel, but on the whole it's fairly easy to navigate.

Lexicon MX400Photo: Mike Cameron

As mentioned earlier, the key difference between the MX400 and the MX400XL is on the rear of the unit. The XL version (pictured) features eight balanced XLR connectors, while these are balanced/unbalanced quarter-inch TRS jacks on the standard model. Aside from this, the rear panels are identical, featuring a single USB port, a footswitch socket for remote control of the unit, standard MIDI I/O (for use in situations where USB is not appropriate) and two sets of S/PDIF I/O (one each for processors A and B). A-D and D-A conversion operate at 24-bit, and both 48kHz and 44.1kHz sampling rates are supported.

Hardware As Software

Of course, the great attraction of the MX400 — as with the MX200 — is the ability to integrate it into the software environment of your studio computer. Installation of the drivers and the stand-alone and plug-in versions of MX-Edit proved very straightforward on my test PC system. As shown in the screenshot on the left, the software front-end is almost identical to that supplied with the MX200, the only exception being in Dual Stereo mode, where Tabs are provided for toggling between the A and B processors. While it obviously involves mouse control rather than 'hands-on hardware', the software does provide dedicated sets of controls for both effects engines within each processor, and this clearly makes it easier to do detailed editing work in the software environment.

When you're using the VST versions of MX-Edit, four different plug-ins are provided, each dealing with a different audio routing configuration. Interestingly, selecting one of the plug-ins automatically resets the hardware's System Configuration setting, whereas with the stand-alone MX-Edit this has to be adjusted via the MX400's front-panel System button. At first, I couldn't get any of the plug-ins to load inside Cubase SX. However, a quick trawl of the Lexicon web site soon revealed an FAQ about disabling the MX200's MIDI I/O within SX, in order to overcome this problem, and the same solution worked with the MX400. After this, the communication between SX and the MX400 worked a treat and (the mass of audio cables aside) using the MX400 via the plug-ins was straightforward. 

When used as a plug-in, the MX-Edit software comes in four types, including the Surround configuration shown running here inside Cubase SX.When used as a plug-in, the MX-Edit software comes in four types, including the Surround configuration shown running here inside Cubase SX.Photo: Mike Cameron

This initial problem I encountered is obviously something that has been around since the MX200 was introduced. While it was very easy to solve, it would be useful if Lexicon could add some PDF documentation to the install CD that details the configuration of the MX400 hardware/software combination with some of the more mainstream sequencers, just to ensure that new users get off to a trouble-free start.

The Real Deal

Paul White's positive comments about the processing abilities of the MX200 apply equally here — except that you get double the options to play with. As with the MX200, the MX400 provides much of that Lexicon reverb magic (plus some other top-notch effects) for a very reasonable price. Unless they're fortunate enough to be working in a high-quality audio environment, I'd be surprised if most users would really feel the need to spend the extra £1000 required to buy into the upper end of the Lexicon range.

I suspect that most users would predominantly employ the MX400 in Dual Stereo mode and, therefore, have two independent Lexicon multi-effects processors available for tracking and mixing duties, from a single rack unit. However, the MX400's Surround mode is more than just a routing gimmick, and while it might only provide four output channels rather than five (or six for 5.1), the various factory presets demonstrate that the unit is more than capable of providing some very convincing surround reverbs.

Many of us are buying into the whole plug-in world, but dedicated hardware still has a tremendous amount to offer — and reverb is perhaps one of the key areas where many might feel hardware still has the edge. Almost anything processed by the MX400 sounds great (OK — except for my singing!) and it adds a dash of sonic class to almost any mix. The plug-in option and USB editing work very well, although I agree with Paul that it would be great if users had the additional option of using the USB connection to pass audio to/from their computers. This would, of course, entail a very different design strategy, and as it stands the MX400 is equally at home in a studio or live context. While those wanting the Lexicon sound on the tightest of budgets will perhaps find that the MX200 fits their needs, for the slightly more well-heeled the additional flexibility and surround capability provided by the MX400 are well worth the additional cost. 


  • Easy to use — with or without a computer.
  • Extremely flexible processing options, including surround support.
  • Most of the Lexicon magic at a competitive price.


  • Not really any, aside from number of audio cables required.


The MX400 provides an excellent combination of flexibility, processing power and good price, with four-channel output providing surround support for those who need it.


MX400 £499.99; MX400XL £549.99. Prices include VAT.

Harman Pro UK +44 (0)1707 668181.

+44 (0)1707 668010.