I just want to add, and I hope it's not too much information: One of my frustrations with published frequency response curves for microphones is that no one (to my knowledge) follows the DIN/IEC standard, which specifies that the measurement should be made (in effect) so that proximity effect isn't in the picture at all. Instead, most manufacturers of professional studio microphones make their measurements and then adjust the curves to reflect what the response would be like at a 1-meter distance. This basically means that all published curves for directional microphones are artificially boosted to some extent at low frequencies.
The degree of this boost depends largely on the directional pattern. It is greatest for figure-8s, less for hyper- and supercardioids, less than that for cardioids, and almost negligible for patterns between cardioid and omni, such as "wide cardioid". In other words, it is greatest just where the actual low-frequency response tends to be weakest, and least where the actual low-frequency response tends to be strongest. Thus it conceals some of the effect that one's choice of pattern has on low-frequency response for more distant recording.
Manufacturers are essentially forced to do this because everyone else has been doing it for so long. I don't see any prospect of the cycle being broken any time soon. Instead, I've seen something like the reverse occurring: In recent years, some manufacturers have decided to use even closer (smaller) measurement differences, which makes the effect even more severe.
I break this down into two general cases. One is speech/communications microphones, on the theory that their published graphs should show the frequency response that would be obtained at miking distances typically used in that application. There would be real justification for this practice, in my opinion, IF such graphs were clearly labeled and especially if the more typical one-meter curve were also shown.
- I fear that many people on this forum, who have bought small directional microphone capsules designed for speech and other communications applications, may have fallen into a trap--with wishful thinking being another powerful motivating factor. I always caution people to read the manufacturer's product descriptions carefully. I've been involved in writing those descriptions myself for over 40 years; it is done very carefully by the better manufacturers. If the manufacturer says that their directional microphone or capsule is intended for speech or communications applications (as the very large majority of all microphones in the entire world are--music recording represents only a small sliver of the market), that generally means that their response has been tailored for use at distances such as maybe six inches from the sound source, where proximity effect is strong. Such a microphone or capsule cannot have full-range response when it is used for more distant recording, unless it's a pressure transducer (i.e. a pure single-diaphragm omni).
More regrettably in my opinion, some manufacturers measure their directional microphones (or "correct" the curves of measurements originally made at greater distances) so that they show the response at, say, 30 cm (about one foot) instead of the usual one meter--but in this case purely for marketing reasons, because it makes the low-frequency response look better for all-purpose recording,
not because close speech pickup is the primary application. To me that seems ethically questionable, but at least two of the companies that I know for sure have been doing it are otherwise very fine manufacturers. It muddies the waters, and people should keep it in mind when comparing graphs--but you may have to write and ask the manufacturer what the measurement distance was. I've done it, and I hope that the more people do it, the more open the companies will eventually be about the practices that they're following.
--best regards
Topic: What Microphone Is This? (Read 3432 times)