The Shure folks loaned Musictech College a pair of KSM141s, probably with the expectation that they would get them back in a reasonable period of time. Six months later, we're still "testing" them. This is Shure's blurb on the KSM141:
"Th e Shure KSM141 is an end-addressed condenser microphone with mechanically switching dual polar patterns (cardioid and omnidirectional)."
The list price on these little guys is about $1500 for a "matched pair." Street price is closer to $800 for a pair. Compared to many of the products in this price range and with these product features, the KSM141 is incredibly competitive. However, there aren't many microphones in this price bracket with comparable features.
The advantage of a mechanical polarity selection system should be obvious to anyone who has dealt with multi-pattern small element mics and their fine-threaded capsules. Even with years of experience, I lose a little piece of self-confidence every time I thread an omni/cardioid capsule on to a mic body. I haven't yet managed to cross-thread a capsule, but it will happen, eventually. The combination of fine threads and aluminum bodied microphones is an accident waiting to happen. My initial concern was that the mechanical polarity selection switch would be . . . delicate. Maybe too delicate for the heavy-handed tactics of music school students. Nick Wood, from Shure, assured me that wouldn't be a problem and was actually interested in seeing how his product held up under our less-than-ideal conditions. At the school, we've used these mics several dozen times in the past few months and every person who's held a KSM141 has had to hold the mic up to the light and watch the acoustic baffle open and close, at least a few times. The mechanism has had a workout and it's as solid feeling today as it was when I first used the mics. I'm no longer concerned with this aspect of this microphone's reliability. Shure's polarity pattern switching mechanism was designed to work over time and through abuse.
Shure sells the KSM141s in a "matched pair" set, including a case, shock mounts, storage bags, and miscellaneous hardware. However, "matching" is something the Shure engineers say is unnecessary with this product, since their quality control is tight enough that all of their high-end products could be called matched sets simply by model numbers. I found that these two mics, placed 4' from a grand piano and summed out-of-phase into a pair of Trident preamplifiers, matched each other at least as well as the two preamps with a single source. This is the 2nd Shure "matched set" that has performed this well, so I'm beginning to suspect that Shure's quality control is exceptionally tight.
The polar patterns are as predictable as you'd hope a small to mid-sized condenser element would provide. The cardioid pattern provides an excellent off-axis response curve and only becomes non-directional at very low frequencies. I couldn't detect any caving of the polar pattern at audible high frequencies. The omni pattern is equally predictable and is as smooth and flat as my calibration standard microphones.
I compared the KSM141's sound quality to AKG 451s, SM81s, Neumann KM184s, and the Studio Projects C4 small element condensers. While all of these instruments had identifying and worthwhile characteristics, I consistently found the KSM141 to be a highly accurate and warm condenser for the applications I normally mic with this type of instrument. The 141's discrete Class A amplification is probably a contributor to the transparency and low self-noise of the microphone. With a high-quality low noise preamplifier, the KSM141s are practically invisible in the signal chain.
The KSM141's flexibility is enhanced by the built in features, such as a 17Hz subsonic filter, a 3-position (0 dB, 15 dB, and 25 dB) pre-attenuator, and a 3-position high-pass filter. I used the 141s individually or in a pair for overhead drum kits, percussion instruments, a small horn section, acoustic guitars, violin, acoustic bass, snare drum (top and bottom side), and high hat. The worst I could say about the KSM141 is that it reproduced the acoustic environment in which I placed it accurately and without coloration. Sometimes, coloration is a good thing.