Shure KSM137 and KSM141: Fantastic Small-Diaphragm Condenser Microphones

Just wanted to pass along this tip about an amazing set of mics. If you need to record acoustic guitar, drums, piano, or entire acoustic bands/ensembles in stereo, you might be looking for the right pair of small-diaphragm condenser microphones. After trying them out on a friend’s acoustic guitar, I’m convinced that the Shure KSM137 matched pair has the greatest bang-for-buck in the industry. These punch well above their price class. Shure also offers the KSM141, which is almost the same thing, but provides both cardioid and omni polar patterns at a bit of a higher cost. The KSM137 only does cardioid.

If you are recording in a home studio, you probably prefer the more directional qualities of the cardioid pattern anyway so as to minimize picking up room reflections and bleed. So if the omnidirectional pattern isn’t important to you, just get the KSM137. If on the other hand you’ve got a larger, acoustically-pleasant recording space to work with, you’ve got to try a pair of true omnidirectional microphones (such as the KSM141) set up in an AB spaced pair for stereo recording. Unlike cardioid mics and most multi-pattern large-diaphragm mics that use dual cardioid capsules to produce an omni pattern, true omnis use a single omnidirectional capsule, and that gives you an almost ethereal transparency. It also has no proximity effect, meaning you can record incredibly close to the source without changing the timbre. It is something worth experiencing at least once if you’ve never heard it before. If you’re not sure what any of this means, here’s more info about microphone polar patterns, why they exist, and what they do.

If you ask a typical gearslut what to get, they’ll tell you that the Neumann KM184 pair is the king of all small-diaphragm mics. But a pair of those costs almost $1000 USD more than the Shure versions! To my ear, my friend’s pair of KSM137’s sounded exactly the same as a pair of KM184’s, if not slightly better. To prove this, here’s a video that compares the two.

A comparison between three microphones on an acoustic guitar, including the KSM137 and KM184.

Take that to the bank. They also sound noticeably more high-fidelity to me than a pair of the popular Rode NT5’s, but that’s to be expected given the NT5s’ low price. In my opinion, the true kings of small-diaphragm mics are companies like Schoeps and DPA, but their products are priced way too high for the average home studio musician while offering diminishing returns as the cost increases, so I won’t go into detail about them here.

Why do the Neumanns cost so much more? Are they that much better in some way? In my experience, the practical answer is no. Most of the extra cost is essentially to pay for the recognition of the Neumann name. On the inside, the design and circuitry are not appreciably different or superior in the Neumanns vs. the Shures. There’s no reason to pay Neumann prices these days (unless you value the Neumann brand recognition, or if you have clients who request Neumann gear).

You may be wondering about the difference between large-diaphragm and small-diaphragm mics. To summarize it, small-diaphragm mics pick up more transient details and are generally more accurate and true to the source than large-diaphragm mics, but this comes at the cost of slightly higher self-noise. Practically speaking, they are preferred on sources where capturing as much detail as possible matters. This could be acoustic guitars, drums, acoustic ensembles, etc. Large-diaphragm mics are preferred when capturing too much detail could work against you, such as in flutes/woodwinds and choirs, where they tend to de-emphasize undesired breath/air noise compared to small diaphragms. They also minimize finger/key clicks when miking acoustic instruments up close. It’s really a matter of taste.

I hope you’ve found this tip helpful. Save your money and enjoy making music!