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Lexicon LXP15 II

Multi-effects By Paul White
Published May 1995

Paul White looks at the latest incarnation of the LXP15 and finds that it neatly bridges the gap between Lexicon's budget products and their top‑of‑the‑range pro reverb units.

It seems ironic that it took over six million years of evolution for man to do with technology what nature managed to do perfectly well with just a few large rocks! Reverberation is simply the result of sound bouncing back and forth between reflective surfaces, but trying to duplicate the effect, substituting thin slices of silicon for big chunks of stone, is no simple task. Though Lexicon would be the first to admit that even they haven't quite caught up with nature, they're still the undisputed big name in artificial reverberation, and the LXP15 II is their latest product.

The new unit appears to be based on the original LXP15, but with the addition of new effect algorithms, so though the hardware may be familiar, when it comes to sound, much of what you hear is brand new. The LXP15 II is a multi‑effects processor but its processing power is directed towards quality rather than quantity, so don't expect to be able to string a dozen or more effects together in one patch. As you might expect, the main aim of the unit is to provide high‑quality, versatile reverb treatments, and a high proportion of the 128 factory presets are studio reverb settings. The remaining patches rely mainly on modulated or unmodulated delays and pitch shifting, often in combination with reverb. Extensive real‑time MIDI and footpedal/switch control is offered over various effects parameters, and some of the algorithms allow parameters to be linked to the envelope of the incoming signal to provide effects such as ducked reverb.

Some multi‑effects units can be quite challenging if you want to use them to their fullest extent, Lexicon's own PCM80 being just one example, but the LXP15 II is designed to be very straightforward to use. There are hidden depths to explore, especially if you want to make the most of the MIDI facilities, but in the main, you can get just about anything you want out of this unit after just a few minutes' exploration.

I love the vocal reverbs, which have that amazing quality of being able to totally transform a sound without ever seeming to get in the way.

All the effects are based on algorithms, an algorithm in this case being a preset combination of effect types and parameters. To create a new effect, it's easiest to use a factory preset as a starting point, and after the necessary parameter changes have been made, the edited version can be stored away in one of the 128 user memories, or 'Registers', as Lexicon prefer to call them. You can still change algorithms while editing an effect, but this method may not be quite so intuitive.

Physically, the LXP15 II has a very straightforward front panel based around an LCD window that shows up to five parameters at one time. Rather than using cursors to navigate around the page, Lexicon have arranged five 'soft' buttons beneath the window so that parameters can be selected directly. Value changes are made with the large 'Adjust' rotary encoder, and the various display pages are selected via the 'Page' 16‑way switch. Separate input and output level controls are provided, along with a simple four‑section input level meter; dual‑function controls are noticeably absent.

The rear panel of this extremely deep unit features a full complement of MIDI In, Out and Thru sockets, along with two pairs of signal inputs and outputs on standard, unbalanced jacks. Stereo inputs are provided so that the dry part of the signal can be kept in stereo, but for studio use where the unit is to be fed from an Aux send, either input may be used as a mono feed. Similarly, you can plug in only one output jack and get the effects in mono, but it's my opinion that anyone doing so should be locked up for their own safety! The remaining five jacks are reserved for foot controllers which may either be passive pedals (nominally 50kohms) or switches. How you use five foot controller at the same time is not explained in the manual — perhaps you need a friend and a one‑legged roadie to help?

The Tour

The best place to start when first using the LXP15 II is with the factory presets. With the Page knob turned to Setup, you can either opt to scroll through the preset names and then load one using the Load button (actually, the soft button below the word Load), or you can have a preset load as soon as you select it. As loading takes half a second or so, it is usually easier to use the Pre scan mode and then hit load when you find the patch name you want.

To help make the presets easier to navigate, they are divided into studio effects and stage effects. The first 64 of the presets are designated as studio effects and contain a large number of specific reverb types, while the remaining stage effects tend to be a little more flashy. However, the descriptions 'stage' and 'studio' are somewhat nominal, and all the effects could really be used in either context.

Reverberation is simply the result of sound bouncing back and forth between reflective surfaces, but trying to duplicate the effect, substituting thin slices of silicon for big chunks of stone, is no simple task.

Once a preset has been loaded, it may easily be modified by turning the page knob to the name of the effects type (Delay, Pitch/EQ, Reverb, Level, Mod or Alg) that you want to edit. For example, if you select Reverb, you'll get the option to adjust the Decay, Treble, Bass Multiply (relative bass decay time), Size, and Diffusion. Other pages allow the patch to be named, the user patch destination to be selected, and also access global functions such as MIDI receive channel, memory protect status, display contrast, and so on.

The effects themselves are based on just five algorithms: Delay Reverb, Pitch/Delay, Gate, Plate and Chorus Delay. Using the delay algorithms, it is possible to set up Glide delays, which start with the delay either sharp or flat and then glide back to the correct pitch. Modulated delays produce all the conventional chorus, flange, phase and vibrato effects, and some algorithms, such as Delay/Reverb, include two blocks of delay — one for the Glide effect and one to provide reverb pre‑delay. The maximum delay time available is just over one second.

Pitch shifting effects are available from within the Pitch/Delay algorithm, which has a range of plus one octave to minus two octaves. This algorithm also includes EQ and delay modulation and the pre‑delay block can be switched so that it will continually loop the stored sound for the creation of special effects. Separate delay blocks are provided for the left and right channels, with the left delay being fed back to the input of the pitch shifter for spiralling pitch effects. This is actually a very versatile algorithm capable of anything from a subtle chorus to a sci‑fi cacophony of sound.


Lexicon go in for control in a big way, and the creative use of control can significantly enhance the artistic effect of signal processing. Any sensible effects parameter can be assigned to either MIDI or pedal control, and pedals can be customised and their settings stored. Up to 78 possible control sources can be used, including MIDI velocity, MIDI clock (for tempo‑related effects), MIDI channel pressure, and even the last note played. These are in addition to the more usual continuous controllers such as bend, breath control, MIDI volume, and so on. Using these features, it is also possible to control the pitch of the pitch shifter directly from a MIDI keyboard.

The unit can be set up so that MIDI program changes access either the Presets, the user Registers or a patch map of selected patches created by the user.

The Effects

After recently using the PCM80, I found the effects produced by the LXP15 II more 'straight ahead', but that's not to imply that they are in any way uninspiring. You don't get the PCM80's resonant chord programs and there aren't quite so many opportunities for audio pyrotechnics, but what you do get is a good selection of classic Lexicon reverb sounds, ranging from bright, aggressive percussion treatments to smooth, natural hall simulations. Amongst my favourites are 'Tiled Room' and 'Splattered', both of which are great on bright, percussive sounds, though I also love the Vocal reverbs, which have that amazing quality of being able to totally transform a sound without ever seeming to get in the way.

The delay and chorus effects are first rate — very clean, plenty of movement, smooth and richly warm. Even the pitch‑shifter works better than most mid‑market offerings, though it still isn't quite as smooth as a top‑end, dedicated pitch shifter. Nevertheless, knowing how difficult seamless pitch shifting is, especially when the hardware budget is limited, what you get is useful with the proviso that it is always mixed in with something else and not left completely exposed.

Other effects worthy of note are the excellent ducking delays and reverbs, which provide lots of excitement in the spaces without ever making the mix sound too busy. 'Delay Cloud' is a good example of this. I also like the neat pan and MIDI tempo delay effects, as well as 'LFO Guitar', where the LFO controls the amount of chorus and the input level modulates the LFO speed. A nice one for fretless bass.


One of the problems when reviewing Lexicon products is that you know you can never mention all the details, because their MIDI implementation alone could be the subject of a complete article in its own right. The LXP15 II falls into the middle of the Lexicon range, coming above the Reflex and Alex, but a little below the PCM80, and significantly below the more costly flagship reverb units. It's described as a multi‑effects unit, but I feel that most users will buy it on the strength of the reverb sounds, as that's what still sets Lexicon apart from the competition. Technically, the reverbs are not quite as clean or as dense as on the flagship models, but the overall character is similar and the subjective difference isn't usually that great in the context of a mix. In other words, your ears will still tell you that you're hearing a Lexicon. In fact the reverbs are simply superb, and with enough variety to cover everything from rock and pop to flowing classical or New Age sounds. The multi‑effects are also designed to be musically useful rather than being to overtly gimmicky, and though you only get two or three effects at once, that doesn't in any way detract from the richness of the sound.

The operating system is a doddle, and for most routine applications you won't even need to open the manual. Even so, it's worth reading it through at least once, so that you'll know what the device is capable of. For example, the tempo‑related (MIDI clock) delays can be very useful in the context of a piece of music with tempo changes, but if you don't read the book, you may never discover them.

So, who needs a Lexicon LXP15 II? In the larger studio, the LXP15 II makes a great second or third reverb unit, and the fact that it can handle all the nice chorus and delay treatments really adds to its versatility. In the project studio, it would make a wonderful main reverb for those whose budgets don't run to a PCM80, but for whom the Alex and Reflex don't offer quite enough variety. In all, this is a very well conceived product that combines excellent sound quality, ease of use and affordability in just about the right proportions.

LXP15 & LXP15 II: What's The Difference?

  • All 128 presets are new.
  • The reverb algorithms have been redesigned to sound smoother and more natural.
  • The presets have been separated into Sudio and Live patches. The Studio patches are designed to be used with an aux send/return system (no dry sound) while the Live patches feature appropriate wet/dry mix settings.
  • MIDI Mapping has been added to the MIDI implementation.
  • The user interface has been improved to give more intuitive knob control and now includes an envelope follower.
  • The programs load much faster than before.

Note: Existing LXP15 owners can have their machines upgraded to the LXP15 II. Contact your dealer or call Stirling for details.


  • Great Lexicon reverb sound.
  • Versatile delay and pitch shifting effects.
  • Lots of real‑time control options.
  • Very easy to use.
  • Pro quality at a semi‑pro price.


  • Unbalanced inputs and outputs may not suit some pro users.


All the classic Lexicon reverb sounds with a useful range of multi‑effects programs thrown in.