Every once in awhile, a company comes along can stand the test of time in the ever changing music world. Lexicon is certainly one of those few. In 1971, Lexicon opened its doors and started manufacturing professional studio quality effects units and quickly building an enviable reputation. Today you would have to look very hard to find a professional studio or major touring rig that did not include Lexicon gear.

As Lexicon built a first-tier name for itself in the pro user world, the price points in these realms were such that Lexicon gear was out of reach for most home users. Fortunately, as with all things digital in the last 3 decades, as technology advanced the price points on studio quality gear began to recede. We now are in a revolutionary time when most home users are able to afford to equip their basement studios and small live rigs with equipment previously reserved for "studio rats". Included in this revolution is Lexicon quality and its world renowned rack-based reverb processors. For this review we will be taking a look at the MPX 550 dual channel reverb unit.

The MPX 550



Room ambience plays such an important role in the sound of any music playback situation. The natural acoustic properties (or lack thereof) in a particular space can make or break a gig or recording. Most people who play multiple venues probably encountered situations where the sound was dead or flat. Or even worse, when the sound was great at "sound in", but then went flat once people were added to the room. Echo effects are a great solution for these tough rooms. Lexicon’s MPX550 is designed around the popular echo effects such as reverb, chorus, rotary, and many others.

The MPX550 is a 24 bit, dual channel stereo effects processor that features Lexicon’s own proprietary "LexiChip" engine. It comes in a single space 19" rack mount chassis and weighs in at just 3 pounds. The MPX550 was designed to be easy to use. Unlike other units, you do not need to have an advanced degree in computer programming to operate the MPX550. While this is not an expensive unit (street price of about $400), it boasts many professional features that put it in a class of its own based on a quality to price ratio.

The MPX550 comes with 255 presets and 64 user programs. Programs can be accessed using the scroll wheel on the front panel, or you can push the scroll wheel in and scroll through various banks for faster access.

Each program is efficiently divided into several edit pages, each consisting of four adjustable parameters that appear on a large LCD screen. Corresponding to these four parameters are four convenient edit knobs on the front panel. Each of these knobs are assigned to one parameter appearing on the edit screen making editing functions intuitive, simple, and painless.

The "Cue Program" mode is great for live sound engineers or DJ’s who want to change the program between songs (or even within a song if you are fast!) with very little down time. While one program is running, you can scroll though the other programs until you find the one you want to use. Once you stop on that program, the "Load" button LED lights up to show you that the new program is cued. The screen will revert back to the working program after four seconds, but the "Load" light remains lit. When you are ready to switch to the new program, just hit the "Load" button and it will automatically load in the newly selected program so you can keep the music going without missing a beat. As another option, you can choose to override the "Cue" function so that when you scroll through programs it automatically load the program you stop on without waiting for you to press the button. If you are technically sophisticated you can also use the MPX550's robust MIDI support to cue different programs as well.

The "Tap Tempo" mode is a great feature for the times you want to set the delay time to match the tempo of the music. Just hit the tap tempo button twice at the tempo of the music and you are ready to go. When you need a new tempo setting, just hit the tap tempo button again twice at the tempo of the next song. This is a great feature for live bands and DJs that specialize in "on the fly" tempo changes to keep things fresh.

The MPX550 also includes a built in compressor on every program. You are able to set the parameters for ratio, threshold, attack, and release. This pro quality compressor sits in the wet mix before any of the other effects.

I have been barely able to scratch the surface of the important features loaded into the MPX550. As such, I have included the following feature list borrowed from Lexicon's MPX550 manual to give you a taste of the power this thing packs.

· Legendary Lexicon reverb from proprietary Lexichip
· 24-bit internal processing and A/D/A conversion
· Selectable 44.1 or 48Hz sampling rate
· 255 presets and 64 User programs, including a Compressor Bank.
· Dynamics algorithm with enhanced metering
· S/PDIF I/O (may be set to wet or dry)
· Balanced analog and digital outputs
· Independent processing of each input
· Dual programs that combine two independent effects in four routing configurations
· Multiple delay, modulation, and pitch effects
· Built in digital compressor with four adjustable parameters
· Tap Tempo
· Full MIDI control with software-selectable MIDI Out/Thru connector
· Large, graphic front panel display
· Four Edit knobs for quick parameter adjustment
· Cue Program Mode
· Global Mix, Tempo, and Compressor Modes
· Internal power supply

Test Applications

I tested the MPX550 in two different applications. First I evaluated it on a live sound setup. Second, I added it to a guitar rack system in a studio space. Here are my results from these application tests.

Sound System: For this test I used the Mackie Onyx 1220 mixer with two powered Mackie SRM300 Speakers. The first thing that I noticed was that the drums sounded full and punchy when the MPX550 programs were blended into their mix. The spatial quality of the guitars was excellent. They reserved their place in the mix and sounded immense and robust when run through the mixing board. Vocals were clear and I really liked how the added ambience options gave presence to these lines without making them sound too distant.


Guitar Rack: The MPX550 adds plenty of reverb options for the guitarist. I found that in this application many of the preset effects were a little too strong for the guitar resulting in a "tin can" sound. To remedy this I simply dialed back the effect parameters using front panel adjustment knobs as mentioned above.

These very simple adjustments made all the difference in the world. The adjusted programs made the electric guitar sound huge yet sit well in the overall mix. I especially liked the programs that incorporated a combination of chorus, flange, tremolo, and rotary.

Not limited to electric guitar, I found that acoustic guitars were also more vibrant using plate, hall, chamber, and ambience effects. These types of effects allow you to retain the coveted natural sound of an acoustic guitar, but make it sound like you playing in spatially different rooms, such as a concert hall or small theater.

For bass guitar I like to use compression liberally, but usually tone down on the rest of the effects. This way I get a heavy bottom end sound with great attack. I only use small amounts of reverb and echo on bass guitar because I find that using a lot of these effects tend to muddy the sound of the bass and take away some of the punch. I was quite pleased with the results of the MPX550 to achieve bass tones that meet these tough expectations.

Overall, the thing I like the most about the MPX550 is that you can choose an algorithm with the routing options you like, and just make simple adjustments to suit your needs. It is really just that simple. You do not need to start from scratch and build a confusing algorithm by yourself. All the guess work has been removed.

Final Thoughts

At home, in the studio, or on the stage, the MPX550 is a highly recommended processor, that can easily pull triple duty an all these areas. The versatility in routing options and features makes the investment in this piece of gear well worthwhile since you are unlikely to need more than this unit for all your reverb effects needs. It is designed to be easy for the beginner to use, yet flexible enough to grow with you as you learn its more more intricate workings. The MPX550 earns the "Rig Ready" award for 2005 from GuitarGearHeads.



Review by: Gary Allen

Copyright (c) 2005 Allen & Halberg Publishing, Inc.
All Rights Reserved
Guitar Gear heads is a Division of Allen & Halberg Publishing, Inc.

			Lexicon MPX 550
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