Rane MPE-47
Four channels of one-octave EQ under MIDI control - Rane's "four-channel fantasy machine," priced at $799 and built to be reprogrammed mid-set.
Overview
Rane announced the MPE-47 alongside two siblings - the MPE 28 (a 28-band, 1/3-octave unit) and the MPE 14 (a two-channel, 14-band, 2/3-octave design) - as a "new generation of tonal controllers." The company's own advertising was blunt about what separated the line from ordinary equalizers. It pitched these boxes as "flexible instruments" rather than static tone-shaping tools, and billed the MPE-47 as the "four-channel fantasy machine." That's advertising, but the architecture behind it was real.
The core of the MPE-47 is four channels of seven-band, one-octave equalization. Recording-Engineer (April 1989, p.51) laid out the family at the Rane booth: the MPE 47 carried four channels of 7-band, 1-octave EQ, and across all three models each band offered equalization from +12dB to -15dB. Collectors tend to notice that asymmetry first. It gives 12dB of boost against 15dB of cut, so the box is happier subtracting than adding.
The memory and MIDI layer is what set the MPE series apart from other equalizers. Recording-Engineer (April 1989, p.51) reported internal memory for 128 curves, accessible via MIDI program change commands, with editing handled through MIDI system-exclusive messages. The speed at which curves change is user-definable, and two curves can be combined to form a new one. For a live engineer, the combining feature is the interesting one. It lets you build complex response shapes instead of just stepping through a bank of presets.
Stepping through presets is still the use Rane's own copy sold. The advertising imagined a guitarist whose tone "screams with sizzling brilliance" on a lead, then "instantly switches back to a gutsy punch" for rhythm, all automatic through MIDI sequencer control. It imagined a synth's aftertouch command building "an earthshaking rumble" into a sustained note, then a patch change snapping the same voice to something "crystalline with presence." And it imagined a club engineer dialing in a perfect PA, punching the settings into memory, then recalling them instantly at the next venue. It's marketing copy, but the 128-curve memory and MIDI recall did make that workflow possible.
A Midi Quest v8.0 support listing from the period names the MPE14, MPE28, and MPE47 among the hundreds of devices the software could edit. Third-party editor support suggests owners were programming these units that way.
Mix-Magazine (October 1989, p.285) listed the MPE 28 at $749 and both the MPE 14 and MPE 47 at $799. The units measure 1.75"H x 19"W x 8"D, a single rackspace each.
The MPE-47 splits into an analog filter side and a digital control side. Rane leaned hard on "proven leading-edge filter technology" in the advertising, and the filters are the analog part. The microprocessor control and "exclusive built-in software package" handle memory, MIDI, and curve manipulation. The same MIDI system-exclusive editing that made the MPE-47 powerful in 1989 is also the part most dependent on period software and documentation. Without a manual or an editor on hand, deep programming gets tedious fast.
Reliability and service history for the MPE-47 are not well documented in available sources, and collectors should treat claims about long-term durability with appropriate caution. What is documented is the design intent: a four-channel, seven-band, one-octave programmable equalizer with ±12/-15dB range per band, 128 memory locations, MIDI program change recall, and sysex editing — all in a single rackspace at a $799 list. That combination was uncommon enough in 1989 that Rane could plausibly call it a fantasy machine without blushing.
For anyone chasing one today, the practical questions are the usual ones for late-'80s MIDI-era outboard. Has the memory battery (if any) survived? Is the MIDI implementation intact? Did any period editor software or documentation come with the unit? The filters are the least of the worries, since Rane built its reputation on them.
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