At $599, the MPX 500 multi-effects processor costs twice as much as Lexicon's entry-level MPX 100. That may seem like quite a price vault, but keep in

At $599, the MPX 500 multi-effects processor costs twice as much as Lexicon's entry-level MPX 100. That may seem like quite a price vault, but keep in mind that this unit costs only half as much as the flagship MPX 1, making it attractive to those who yearn for more features and programmability yet hesitate to drop more than a grand on an effects processor. Despite its moderate price, the MPX 500 is powered by Lexicon's proprietary Lexichip (the same chip used in the costlier MPX- and PCM-series effects processors) and boasts 24-bit digital converters and 24-bit internal processing. Additionally, S/PDIF digital inputs and outputs let you connect the unit directly to digital mixers, hard disk recorders, and other digital devices, bypassing the converters altogether.

Rather than taking the every-effect-imaginable-and-then-some approach common to many multi-effects units, the MPX 500 offers a maximum of two simultaneous effects that are configurable in a variety of useful ways. It also provides fairly extensive program-editing capabilities, including four dedicated Edit knobs for near-instantaneous tweaking. The emphasis is clearly on usable presets, with 240 preset programs that need little or no tweaking and cover a wide variety of effects-an important feature when there are only 30 user-program memory locations.

OUTSIDE THE BOXThe MPX 500's user interface is a marvel of simplicity (see Fig. 1), consisting of six knobs, six buttons, and, in the center, a 150-by-32-pixel backlit LCD screen. To the left of the screen (left to right) are the Input Trim knob, buttons for accessing Edit Pages and entering System mode, and the four Edit knobs. To the right of the screen are the Load and Bypass buttons, the Program knob, and buttons for the Learn function (labeled Store and Tap/Cancel). All of the buttons have embedded LEDs that light up when engaged; especially snazzy is the LED on the Tap/Cancel button, which flashes in time to the current tempo. A Power on/off switch on the far right completes the front-panel controls.

On its rear panel, the MPX 500 sports a range of input and output options (see Fig. 2). Analog I/O includes stereo pairs of balanced 11/44-inch TRS and XLR connectors; the S/PDIF digital I/O uses coaxial connectors. A 11/44-inch TRS input allows you to hook up a dual footswitch to control the bypass and tap-tempo functions, as well as MIDI In and software-selectable Out/Thru connectors. The unit has a built-in power supply with a detachable IEC power cable.

DANDY INTERFACEImpressively, the unit's LCD screen presents a wealth of information in a clear and relatively uncluttered manner. Look for and you'll easily find the name, number, and bank location of the currently loaded program and its routing configuration (displayed as a small graphic). The current tempo in bpm, and whether it's global or program specific, shows up in bold relief, as do the names of up to four editable parameters. On the display you'll also notice a stepped bar-graph stereo input meter that indicates whether the input source is analog mono left or right, analog stereo, or digital (always stereo); if digital, it will tell you whether the sampling rate is 44.1 or 48 kHz. Finally, if you're not using the program AutoLoad feature (more on that later), the display communicates the number of the cued program. As a bonus, the LCD screen contrast is adjustable via a small pot on the unit's rear panel.

The MPX 500's programs are arranged in banks and selected by using the dedicated Program knob. Turn the knob and you'll march through the programs sequentially; press it and you'll jump to the next bank. Simultaneously pressing and turning the knob-which can be a little tricky until you get the hang of it-allows you to glide easily from one program to another that is hundreds of numbers away with a quick twist of the wrist.

When a program other than the currently loaded one is selected, the LED in the Load button lights up, and for four seconds the name of the selected program replaces the name of the loaded program in the display. You can then load the selected program immediately or anytime thereafter by pushing the Load button. If after four seconds you choose not to load the selected program, then its number (next to the word cued) will pop up under the name of the currently running program. An AutoLoad feature causes programs to load automatically 0.75 second after the Program knob stops turning.

Each program on the MPX 500 can have as many as 16 editable parameters, arranged four at a time on Edit pages that correspond directly to the four Edit knobs. Though the names of the first four editable parameters are visible within the basic program display, their values are not. As soon as one of the Edit knobs is adjusted, Edit page 1 appears, showing the names and values of the first four parameters. The name and value of the selected parameter are highlighted, making it easy to know exactly what you are doing. The pages can also be accessed by pushing the Edit Pages button, which steps you through each page sequentially. Once any parameter value has been changed, the LED in the Edit Pages button lights up as a reminder.

Edit knob 1 is referred to as the Adjust knob on Edit page 1. In many cases, rather than accessing a single parameter, this knob adjusts a combination of critical parameters simultaneously. For example, in many chamber and room programs this parameter is called Liveness, and adjusting it changes EQ, decay, and early-reflection parameters. The name of the Adjust parameter is always shown in parentheses, making it easy to locate; when you adjust it, a more detailed description of its function appears briefly along the bottom line of the display.

ALL SYSTEMS GOParameters that affect the MPX 500 globally (including MIDI settings, MIDI dumps, and reinitialization commands) are accessed by pushing the System button. Examples of System parameters include Output Level (0 dB/unity gain to -24 dB), Input Source, Clock Source (internal 44.1 or 48 kHz, or external S/PDIF), Mix mode (global or program), Bypass mode (dry/full mute/input mute), Tempo mode (global or program), and Program Load mode (which determines whether the dry signal continues or there is silence when you switch between programs).

Two of the more interesting System options are found under the Digital Output and Operating modes. By setting the Digital Output to Dry, you can use the A/D converter independently of the effects processor. The Operating modes include Normal; Demo, which continually loads one program after another; and Locked, which makes only the programs in the User Bank accessible, disables the Edit and Learn functions, and selects the AutoLoad feature. The Locked mode could be handy when you want to access only the user programs without navigating through the other functions. However, I could not get it to work properly at first. Lexicon looked into the problem and discovered an oversight in the user guide: you have to actually load a user program before engaging the Locked mode-a critical step that somehow got left out of the documentation. After learning the correct procedure, I was able to get the Locked mode to work just fine.

The MPX 500 operates on any of the first 16 MIDI channels and recognizes MIDI Program Change (100 to 127 or 101 to 128), Bank Select, Pitch Bend, Aftertouch, and continuous controller (1 to 31 or 33 to 119) messages, allowing it to be operated remotely from a MIDI sequencer or other MIDI device. You can easily assign any of the MPX 500's editable parameters to a continuous controller (and a controller range can be fixed) by using the Learn mode. The MPX 500 also recognizes MIDI Clock messages and applies a tempo of 40 to 400 bpm to any program featuring tap tempo. Tempo-controlled delay and modulation rates lock to tap or MIDI Clock, and tap tempos can be controlled by audio input, the front-panel Tap/Cancel button, a footswitch, an external MIDI controller, or a MIDI Program Change message.

BANK ON ITAs mentioned previously, the MPX 500 provides 240 preset programs, as well as memory locations for 30 user programs. The user programs cannot be "built from scratch" but instead are simply modified versions of presets. Changes made to presets cannot be saved to preset locations (that's why they're called presets), so even if you change only a single parameter ever so slightly, you'll have to save your new "user program" to one of the 30 memory locations. This could be a serious limitation if you need to have access to more than 30 edited programs at once. User programs can be backed up to a librarian program and recalled via MIDI, but that may not be a satisfactory solution for everyone. You can easily name the user programs using two of the unit's Edit knobs.

The MPX 500's programs are organized by type into 25 banks. For example, plate reverbs are located in bank 0, gated reverbs in bank 1, hall reverbs in bank 2, and so on. The first 104 preset programs use single-effect algorithms, whereas most of the remaining presets are dual-effect programs. The dual programs combine two effects algorithms in one of four different routing configurations (see Fig. 3): Dual Stereo or Parallel; Cascade or Series; Mono Split, which routes one side of a stereo input into each effect and combines their stereo outputs; and Dual Mono, which is the same as Mono Split except that each effect outputs discrete mono.

Banks 0 to 6 contain plate, gated, hall, room, chamber, and ambient reverbs. Digital reverb has been one of Lexicon's specialties for decades, and these complex yet transparent programs are fine examples of the Lexicon sound. Some of the reverb programs are nearly identical to those found in the MPX 1, and a few even have the same name.

The plate reverbs range from thin and metallic-sounding to big, full, and rich. (Oddly, Tape Slap, at both 7.5 and 15 inches per second, is included in the plate category.) The gated reverbs include a straight gate, several tap-predelay gates, and two inverse gates. You can choose to play in a small, midsize, large, or concert-size hall; in a small or large church; or in a special hall for jazz, dance, or synth music. The unusual and interesting Gothic Hall program has 418 milliseconds of predelay and 2.4 seconds of decay; the Adjust knob controls predelay, which can be extended out to more than a second, resulting in bizarre echo effects.

The room programs emulate acoustic spaces ranging from Bedroom and an excellent Tiled Room to the immense Studio A and the dense Fat Space and Chunky Space programs. Chamber reverbs include a nice Basement and two good vocal chambers, along with a Brick Wall that's not particularly convincing and a great PCM60 Large Chamber. The ambient programs are versatile as well as relatively authentic, with Guitar Amb and Marble Foyer being my two favorites.

Bank 7 contains five tremolo programs, which are differentiated by the use of various modulation waveforms: sine, rectified sine, square, triangle, and sawtooth. You can control modulation speed using the Tap function, and the Adjust knob changes the phase relationship between the two sides of this stereo effect. These are some of the best-sounding tremolo effects I've heard anywhere, apart from old Fender tube amps. The rotating speaker programs in bank 8 were much less impressive but still proved to be passable versions of this effect, which is extremely difficult to emulate.

The five chorus and five flanger programs in banks 9 and 10, respectively, are quite good. The six-voice choruses are based on those found in the PCM80, and two of them add a little slap delay before the modulation. Three of the flangers are configured in a 180-degree phase relationship, with the Adjust knob controlling resonance. Bank 11 contains five detune programs, which are voiced similarly to the choruses but are more dramatic and exaggerated. The five stereo polyphonic-pitch programs in bank 12 provide pitch-shifting of two octaves down and one octave up, with adjustments in fine increments. The pitch algorithms sound really good (especially when combined with other effects in the dual-program banks), and I detected only negligible tracking errors.

Bank 13 contains 15 delay-and-echo programs, all of which sound exceptionally clean and crisp. Tap tempo sets the delay time, and the Adjust knob sets the amount of feedback on the first eight programs, whereas on the other seven the Adjust knob sets the delay time. Mono delays can be up to 5.5 seconds, and stereo delays can be half that length. The delay programs feature a very clever Master Delay parameter that scales all nontap delay times within a program by a specific percentage.

Bank 14, special effects, contains 15 intriguing programs employing a variety of configurations. Fans of the Infinite reverb program found in the discontinued LXP-1 will be pleased to find it here. It's basically a chamber with an infinite yet distant decay-think Paul Horn in the Taj Mahal. Infinite Delay links stereo delay times to tempo and loops back on itself with 100 percent feedback. Abyss and Dreamscape both run pitch into reverb; the former feeds a subtle detuning algorithm into a sizzling reverb with a long decay, and the latter generates cascading harmonies into a large reverb with medium decay. Jet Flange lives up to its name in every way, particularly with the resonance cranked up.

The remaining banks contain the dual programs, which combine reverb and delay with one of the other individual effects algorithms. In each of banks 15 to 21, the first six programs are configured as Dual Stereo, and the last four as Cascade. Banks 22 and 23 are configured as Mono Split, and bank 24 is configured as Dual Mono.

APPLY AS NEEDEDI had the opportunity to use the MPX 500 while tracking and mixing in my personal studio, and I found it to be quite useful in both applications. I achieved excellent results when connecting it to my Yamaha 03D digital mixer using the S/PDIF digital output, and it performed nearly as well using either set of analog outputs. In all cases the sound was sharp and clear, with practically no noise or digital artifacts.

I also used the MPX 500 in my guitar rig while performing live. Normally, I run a stereo guitar preamp into an MPX 1 and then connect the MPX 1 to a stereo power amp. When I hooked up the MPX 1 to the MPX 500 via the S/PDIF connectors, the two units worked together like a sort of superprocessor, allowing me to create ultracomplex effects combinations. For example, by using one of the MPX 500's pitch algorithms to process a harmonizer program in the MPX 1, I created massive chords with decidedly otherworldly overtones.

Being able to quickly access and adjust the main parameters of a multi-effects processor by simply turning a knob or two is a great advantage when working against the clock in a studio-but being able to do it while performing live is nothing short of fabulous. I work with an improvisational ensemble, so my ability to change sounds spontaneously at less than a moment's notice is critical. The MPX 500 gives me that flexibility.

SHORT AND SWEET OF ITThe MPX 500 delivers the latest digital technology, extensive I/O, and intelligently conceived and great-sounding programs at a reasonable price. It is ideal for users who need good working presets that can be tweaked to fit quickly and easily, but who don't necessarily require the capacity to store lots of user programs onboard.

Barry Cleveland is the editor of Mix Master Directory and The Recording Industry Sourcebook, and author of the "Pedal Board" column for Onstage. He also plays guitar in the improvisational quintet Cloud Chamber (www.mphase.com/cloud.htm) and operates a personal studio.