Microphone matching is on the mind of this inSync reader. “I am wondering what the real benefits are of having a matched pair of mics over just having two of the same mic.”
There seems to be a lot of mystique around the concept of matched microphones, matched tubes, or matched anything audio for that matter. Also like many things in audio the exact definition of what constitutes matching differs from manufacturer to manufacturer as well. Opinions about this topic are highly varied. The whole concept of matching arises out of a need to have things be matched.
Back in the old days when most things audio, including microphones, were hand made the variances from one unit to another could be significant. Even the raw components had very wide tolerances in some cases. It was possible to pick up two “identical” microphones from the same assembly line and have them sound noticeably different. Once people recognized a need to have consistency between two microphones manufacturers began matching up like mics and making pairs. Matching was basically just a series of steps where the characteristics of each mic off the line were tested and their measurable sonic/electrical characteristics recorded. This data could be used to find microphones that were “alike” within some more or less arbitrary tolerance level as specified by the company. In some cases matched microphones were then subjected to listening tests to ensure the matching. Groove tubes made a business of this with their tubes. They don’t make tubes. They buy the same tubes everyone else does, but they put them into matched sets and charge a premium for them. And given the wide tolerance of some tubes matched sets can be a good thing.
The benefits of matched microphones are that a pair would perform exactly alike, thus making a stereo pair behave in a way that makes a very accurate stereo recording (that’s just one example). If the microphones acted differently your left and right channels would not sound exactly the same, which could result in timbre anomalies between them and a smearing of the stereo image. The sad thing about many of the old matched microphones is that even though they were matched at the factory they would still drift away from each other over time. It’s just the nature of the beast.
Nowadays with modern manufacturing techniques products, including microphones, can roll off an assembly line for hours and all of them will be as closely matched as the “matched” pairs of yesteryear, and they stay that way. Most manufacturers do not even offer “matched” pairs of mics anymore because of this. Some that do use it as a marketing tool, but it is arguably unnecessary. Matching is only needed when the tolerances are so wide in the first place that there are noticeable differences from one unit to another, which just isn’t the case with most modern designs.