The "misinformation" occured when DJL extended Alan's original remark to imply something very different.
For "drum overheads", where you're using close miking for the other drums, some small differences in frequency response between the overhead mics ain't gonna kill ya in terms of getting a good recording.
About the only place where it might be a bit of problem is in an x/y setup, but that's not how most people do their overheads. Even then, it would take some radical differences to be heard, since each mic is picking up different drums. For some songs, we purposely use different, non-matched, overhead mics to accentuate what we want.
DJL took Alan's "use the dots for overhead mic matching", and extended that remark to assume that the dots would insure a perfect set of matched mics from any two similar SP mics, with the same color dot.
Perhaps Alan was too ambiguous in assuming that people would simply take his remark as being exactly what it was (i.e., "use the dot's and you'll be close enough for that particular application, drum overheads").
Is it misleading? Yes, and no. The SP mics are pretty much made the same way from unit to unit. The peaks and dips will vary a bit from mic to mic, but will generally be in the same ball park. Same thing is also true for MXL, Rode, Neumann, AKG, and most other manufacturers you'd care to name. Those small frequency differences between identical mic models are really out of the control of the manufacturers and are due to slight variations in the materials used.
There are also differences (called "tolerances") in the resistors, capicitors, and FETs used in a mic. These will usually cause a difference in the output level of the mic. While "these" tolerances can be more tightly controlled, it's expensive and slow to hand sort and test each resistor, capacitor, and FET that goes into each mic. But you can easily measure the overall output of the mic, and put some indicator on the package.
So the dots help you get reasonably matched levels, and hopefully, the assembly of the capsules is consistant enough to get the same "general response" from mic to mic.
To exactly "match" the mics would require far more testing, consisting of taking the run for the day, and hand testing each mic, saying in essence, "OK, let's look for some that have almost identical responses" - a very slow and involved process. That's why manufacturers charge more for matched pairs.
For drum overheads, at this price point, the dots should do a "good enough" job. Not perfect, but good enough for the application. For more critical applications (like x/y miking a string quartet), you'd want a set of absolutely matched, high dollar mics. But, let's say you can't afford anything but cheap mics, and you still want to record a string quartet. If I were doing it, I'd use similar dots to find the highest output mics and match from there.
A lot of people get really anal about this stuff, but for most applications, there's a big difference in price, but NOT a big difference in sound between "great" and "good enough". Alan said it was "good enough" for drum overheads.
Around Sunday morning folks will be posting "PLEASE MAKE IT STOP!!!!!"
