by Steve Cunningham

Lexicon is to reverb as Xerox is to photocopies, and they’ve established themselves as the market leaders for quality reverb processors. The company produced the first commercial digital delay line (the Delta-T 101) back in 1971, and it has always been known for their high-end studio effects. Back when I was a degenerate rock musician, I drooled regularly over the Lexicon Prime Time delays and 224 reverbs we used in recording studios. I was fortunate to acquire a couple Lexicons in the mid-’80s at fire-sale prices — a used Model 200 reverb (circa 1983, list $5000) and a new PCM-70 (circa 1987, list $2500). I still have them both and they’re among my favorites, in some cases besting some fancy software plug-in reverbs.

So when the editor of RAP told me there was an MPX500 on its way to me for review, I was more than ready. What I was not ready for was how much Lexicon sound you can get today for a list price of $599.


The Lexicon MPX500 is a dual channel (and true stereo) effects processor, offering a range of routing configurations and two simultaneous effects. There are six reverb types as well as tremolo, rotary, chorus, flange, detune, pitch-shift and delay, arranged into 240 presets, with an additional 30 user locations.

The effects are generated by the same 24-bit “Lexichip” found in the earlier MPX1 and MPX100 units, but the MPX500 has 24-bit A-D and D-A converters that the others lack. In addition, the MPX500 has S/PDIF I/O for those who want to connect digital equipment.

The front panel is dominated by a backlit LCD screen that shows the current preset number, name, and editable parameters. Four stepped, continuous parameter knobs can be found to the left of the LCD screen, and they correspond to the four parameters that are displayed at any one time along the bottom of the screen. To change a particular value, you simply turn the appropriate knob. There are up to sixteen different editable parameters per program, and a Page button is provided to help you navigate through them in groups of four. The current page number is displayed in a “Page X of 4” format.

The LCD also handles the input stereo metering and output-level adjustment as well as showing patch name and location details. To the right of the display is a stepped rotary control that is used to move through the available programs, and the system setup page provides the option to have patches load automatically after just under a second when you stop turning the knob. Alternatively, you can opt for the more traditional Lexicon approach of using the Load button to load in the selected patch. The Load button has long been a standard feature of the Lexicon PCM series, and I’m just glad you can disable it here as on the PCM units. I find it annoying to have to press yet another button to get the program to load. I can see its usefulness in a live situation where you need to see the patch name before it changes, but for production, its clumsy.

Also to the right of the display are buttons to Bypass the effect, to Store an edited program to a User slot, and a combination Tap/Cancel that lets you establish the speed of a periodic effect by tapping the button in time.


The rear panel features analog audio connections that are balanced and are available on both XLR and TRS ¼-inch jacks, as well as the aforementioned S/PDIF connections on RCA jacks. The analog inputs and outputs use 24-bit converters, and Lexicon claims a dynamic range of 105dB. The AC power connector is a standard IEC socket rather than the external wall wart that is common on products at this price point. There are MIDI IN and MIDI OUT/THRU jacks, with the latter being software-selectable for OUT versus THRU use, that are used for patch dumping, real-time parameter control or tempo control.

The only other things on the back panel are a footswitch jack for activating bypass or tap functions, and the screen contrast knob. Mounting the contrast knob on the back is a serious design flaw in this reviewer’s opinion, since it makes it nearly impossible to adjust the contrast once the unit is mounted in a rack.