Sennheiser MKH-20
An omni condenser that shows up wherever a hall has to be captured without a forest of stands — including, per the trade press, hanging over a symphony.
Overview
The MKH-20 is the omni member of Sennheiser's MKH condenser family, and the documentation that survives it is almost entirely about how it was deployed rather than what it measured. DB-Magazine (January 1987, p.74) described the MKH 20 P48 as a transformerless omni-directional studio condenser built around the same symmetrical capsule design used across the range, and noted it was considered well suited to reproducing acoustic string and wind instruments. That is the short version of the mic's case: an omni with no transformer in the signal path, intended for natural capture of instruments that live or die on their timbre.
Where the MKH-20 actually earned its reputation was in classical and symphonic reinforcement, and the record of that is unusually specific. A Recording Engineer account of sound designer Joseph Magee's work at the Hollywood Bowl describes a system built deliberately around as few microphones as possible — typically fewer than a dozen Sennheiser, Coles and Schoeps mics for a performance that might put nearly 100 musicians on stage. Magee's primary stereo pair was two outer MKH-20 omnis spaced 20 feet apart and panned hard left and right, run about 6 dB hotter in the mix than a near-coincident pair of MKH-40 cardioids set center stage roughly 12 inches apart. The reasoning is the useful part for anyone trying to understand what an omni buys you in a big room: the widely spaced omnis carried the image and the sense of the hall, while the cardioids filled the center. Magee's stated priority was an exceptionally clean input path and the best possible signal-to-noise ratio, because without a very low-noise system the gain needed to present a well-defined soundfield is simply out of reach.
The same approach shows up in a very different production. A Recording Engineer account of the Electric Light Orchestra Part II tour with the Moscow Symphony describes a five-mic overhead ensemble system in which three MKH-20 omnis formed a center "tree" suspended about 10½ feet above the symphony risers, with an additional pair of outriggers spaced about 28 feet apart to catch brass, percussion and the string sections. The engineer's note on why the overheads mattered is blunt: a typical classical date has a live, reflective hall to work with, and this one did not, so the mic choice and placement had to do the work the room couldn't. For choral pickup in the Bowl system, three spaced MKH-20 omnis went up above the vocal risers, fitted with custom foam discs — Magee noted the foam on the backside of the mic cut wind noise and attenuated the off-axis high end, letting a large vocal group be captured with the fewest possible microphones.
The MKH-20 was also the reference point other microphones got measured against. A BE Radio account of a week-long microphone comparison at Minnesota Public Radio's Performance Today — pianist Jeremy Denk in residence, sessions with Pepe Romero and Quartetto Gelato — ran a set of Neumann M150 tube mics against a respected assemblage of contemporary and vintage condensers that included the Sennheiser MKH20 alongside Neumann KM63 and KM86 examples. Every mic in the comparison went through Millennia Media preamplifiers and a Studer 950-S digital board. The engineers kept all the mics up all week and compared them on every new instrument, player and style — the working assumption being that repertoire makes a difference and different styles call for different sounds. Being the Sennheiser in that lineup is its own kind of credential.
Studio-Sound (June 1987, p.74) noted in a three-microphone test that the mics shared a lightweight steel tube body flattened on two sides, ran transformerless outputs to eliminate transformers from the signal path entirely, and that the example under test was unusually tolerant of handling noise and quite good on wind noise and popping — with measured behavior in complete agreement with the manufacturer's published data. That last point matters more than it sounds: a mic whose bench performance matches its spec sheet is a mic you can specify blind. The same article places the MKH-20 within a family introduced to meet the demands of digital recording, with improved distortion and self-noise figures and higher SPL handling than what came before — Studio-Sound (April 1993, p.22) dates the current MKH condenser series to 1985, beginning with the MKH-40 cardioid, with the omni MKH-20 and figure-of-eight MKH-30 joining as the range filled out.
What the documentation does not settle is the mundane stuff a buyer wants: original list price, confirmed production start and end years, and any catalogued common failure modes are all absent from the available material. Collectors report that used examples circulate, but no reliable current market pricing or parts-availability information is present in the sources here, and none should be assumed. The honest way to read the MKH-20 is as a working omni that got specified by people who had to make a symphony sound right outdoors on the first take — the kind of gear that becomes a standard because it keeps being the safe answer, not because anyone wrote a glossy review of it.
Similar items on eBay
No exact Sennheiser MKH-20 listings are live right now — these searches show current Sennheiser and similar vintage audio gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.