Gunnar, the term "matched pair" is certainly open to abuse, and it actually is abused sometimes, particularly by sellers of used equipment. But for a serious manufacturer such as Neumann it isn't a casual matter or just a slogan to be thrown around without any meaning. I think that we benefit greatly from the attitude which certain manufacturers take toward their work, and I like to see that appreciated. Companies such as Neumann are still operating in a professional manner even though many of their customers nowadays aren't professionals. And when they say "matched," they actually mean something by it.
As far as I can tell, pair matching wasn't an explicit concern before the late 1950s when stereo recording became common. Before then the issue was the more general one of consistency in production, i.e. if you've used one U 47, do you then know what you can expect from another one? As Neumann began to produce stereo microphones starting with the SM 2 in 1957, they began to select the capsules for those microphones, since the entire basis of coincident stereo recording is a very close match between the microphone channels. This practice continued with their later stereo and quadrophonic microphones.
With the introduction of the K 67 capsule in 1960, Neumann's capsules themselves were now being built from halves which required selection and matching so that the synthesized omnidirectional and figure-8 patterns would come out correctly. (That had always been a problem in the U 47 and particularly the U 48.) And the multi-pattern KM 66, and later the KM 76 and 86, were made with a pair of cardioid capsule heads enclosed within a larger, screened enclosure, and those two internal capsule heads were specially selected as matched pairs. If you sent Neumann one of those microphones for repair and one of the capsules was defective, they would replace them both, and they would charge extra for their selection as a matched pair.
Similarly, by this time Neumann would provide selected, matched pairs of any of their microphones for an additional fee (or sometimes, I suspect, simply as a favor to an important client). They didn't publicize this, however; they have long been one of the manufacturers that claim their microphones to be so consistent that specially matched pairs aren't required. But very small shifts in the balance of a stereo recording can have a significant influence on how the sound is perceived, and I think that if they could economically produce their microphones within even narrower tolerance limits, they would be glad to do so.
Anyway in the late 1990s Neumann began to introduce factory-matched "stereo sets" of some models; if a match could involve consecutively-numbered microphones, that was done. Then the U.S. branch began to sell their own "stereo sets" of additional models in which the microphones weren't selected as matched pairs (something which only the factory could do) but which had consecutive serial numbers. The success of that program persuaded the company as a whole to start selling "stereo sets" of further models--and with the factory now involved, it became possible to provide both matched capsules and (quite often) consecutive serial numbers. So that is how things stand today.
--best regards
Topic: microphone matching (Read 8381 times)