Rane RE-27 Realtime Analyzer
A third-octave analyzer that used three LEDs per band instead of a wall of them, and saved broadcasters money doing it.
Overview
Most realtime analyzers of the early 1980s made their point with sheer LED count. Row after row of little lights ran across the front panel. Rane went the other way with the RE-27. Instead of the usual multiple-LED matrix per filter band, it used a simple, color-coded arrangement of three LEDs per band. Modern Recording (February 1983, p.56) singled out the design as easy to use and a genuine cost saver. The analyzer was a tool you calibrated a room with, not a light show you stared at.
The RE-27 is a 27-band third-octave equalizer/analyzer. Modern Recording (February 1983, p.55) confirmed that its filters maintain constant bandwidth at every setting of the slider controls. That matters because constant-Q behavior keeps a third-octave boost from smearing into the neighboring bands when you push it hard. The same review plotted the boost and cut characteristics of each of the 27 bands with a multiple sweep on a spectrum analyzer.
The green/amber/red logic is how owners actually used it. According to the period review, a red LED lights when response is too high in a given band, while green LEDs light when response falls within 3 dB or 1 dB, depending on how the unit is set. That gives you two targets. Work to a loose ±3 dB for a quick room flattening, then tighten to ±1 dB when you're chasing the last few nodes. It turns a spectrum display into a go/no-go alignment tool, which is handy for an engineer working at 2 a.m. before a session.
Signal handling is straightforward. An equalization level control at the left of the panel governs the volume of signal through the equalizer section and can be adjusted for up to +12 dB of gain, per Modern Recording (February 1983, p.55). The built-in pink noise generator puts out from 0 to 1.2 volts (+4 dBm) to match the input level requirements of whatever mixer, amplifier, or downstream equipment is being driven. That pink noise is pseudo-random rather than truly random, and it is CMOS digitally synthesized from a 30-bit word.
In the Field
The RE-27 earned its keep in broadcast facilities, and the record bears that out. A survey of the Museum of Television and Radio's New York studio lists an Electro-Voice RE-27 host microphone alongside a rack that included a Rane HC-6 headphone amp. Elsewhere, a Dallas Radio One facility's equipment list names the Electro-Voice RE27 among its microphones, and an AMFM Orlando studio buildout specified Electro-Voice RE-20, RE-27, or Shure SM7 microphones across its control rooms. Note the naming collision here. The "RE-27" in these broadcast inventories is the Electro-Voice microphone, not the Rane analyzer, and the two get confused constantly in listings and forum threads. The Rane RE-27 is the rackmount analyzer. The Electro-Voice RE-27 is a dynamic broadcast mic. A buyer searching "RE-27" needs to know which one is in the box.
That confusion affects how these units surface today. The analyzer was a niche professional tool, and it shows up in studio and broadcast clear-outs rather than in collector-focused sales. The constant-bandwidth filters and the +12 dB equalizer gain keep the unit useful for room tuning decades on, provided the sliders and LEDs are still healthy.
Buying and Maintaining
The RE-27 was built for installation rather than touring, so the usual failure points are the ones you'd expect in a rack unit of its age. Slider pots get dirty or scratchy after years of room-tuning sessions, and LEDs or driver circuitry in the display section age. Check the pink noise generator and the equalizer section first on any used example. Confirm the noise output actually reaches its rated +4 dBm ceiling and that each of the 27 bands still boosts and cuts cleanly. A unit with dead bands or a weak noise source is a parts donor.
Verify the model number carefully given the Electro-Voice name overlap. Ask sellers for a photo of the front panel with the unit powered up so the LED behavior can be assessed before purchase.
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