Beyerdynamic M 201

by Andrew Thompson

The Beyerdynamic M 201 is an end-addressed, “pencil”-style dynamic microphone with a relatively unusual (for its type) hypercardioid pattern and a broad published frequency response of 40Hz – 18kHz.

The body is constructed from brass and appears extremely robust. The microphone’s diaphragm is made from a proprietary material named Hostaphan, reportedly a polyester film similar to Mylar, and the physical shape of the end-address package suggests it is seated close to the microphone’s grille. Audio is carried via the standard XLR 3-pin connector, and new retail packages include a microphone clip and windshield. The microphone is a transformer-coupled design and features a hum-cancelling voice coil which is intended to reject electrical interference from nearby AC sources.

Response

The manufacturer claims a useful response to frequencies between 40Hz and 18kHz, an unusually wide range for a dynamic cardioid. The currently available model at the time of writing is called the M 201 TG (apparently the “Tour Group” model, incorporating minor physical changes, make the body more durable), which lists its sensitivity as being 1.2 mV/Pa (-58 dBV). Previously available models include the original M 201 N (N denoting the mic’s low 200ohm impedance; this model features a DIN connector instead of the XLR), M 201 N(C) (which first incorporated the XLR connector, here designated by the initial of its inventor James H. Cannon), and also the M 201 N(C).02 which also featured a switchable high-pass filter. Beyerdynamic maintains that apart from these differences the microphone has been manufactured essentially identically for many years – older spec sheets list the M 201 N(C) as enjoying a listed sensitivity of 2.0 mV/Pa ± 1.5 dB (-54 dBV), but any apparent discrepancy would be within the stated tolerance, and indeed the various models are seemingly identical in all other meaningful respects.

On-axis response is nominally neutral from 150Hz to 1kHz, becoming slightly boosted in the upper midrange – nearly +2dB between 2 and 5kHz, rising to a +4dB peak between 10 and 13kHz. High-frequency roll-off begins at 13kHz, crossing zero at about 18.5kHz. Sensitivity declines gently below 150Hz, reaching -8dB by 40Hz.

Like all pressure-gradient microphones the M 201 exhibits proximity effect; enhanced loudness of low frequencies in the microphone’s output when the microphone is within a certain distance from the source, increasing with proximity. Nominal free-field frequency response is plotted at 1m from the diaphragm. At 10cm an enhanced response of some +8dB is to be expected at below around 90Hz, and of up to +19dB at 2cm. Response becomes gradually more linear above 100Hz, converging around 1.2kHz.

The hypercardioid pattern is reasonably stable and consistent between 250Hz and 2kHz, being tightest at 1kHz with attenuation in the order of -10dB at 90 degrees off-axis and around -12dB at the rear, and showing well-defined null points at the expected 120 and 240 degrees off-axis. At 125Hz the pattern is still recognisably hypercardioid, though attenuation between 90 and 120 degrees is reduced to the extent of compromising the null points. Above 2kHz the rear lobe is reduced and the pattern tends toward a cardioid shape, in fact losing its null points altogether at 4kHz, though it maintains around -6dB attenuation at 90 degrees and even a distinct rear lobe at around 8kHz, which compares well with other microphones of its class.

Uses

The M 201 is intended primarily as an instrument microphone, and its frequency plot bears this out, providing full coverage of its claimed spectrum of frequencies while indicating no intent to flatter or enhance any particular area of it. As a dynamic microphone it should withstand very high sound pressure levels with no difficulty, and this in concert with the linearity of its response recommends it for a wide range of sources.

It’s fair to say that the range of hypercardioid and supercardioid dynamic microphones available on the market is comparatively limited, and this scarcity lends the M 201 a degree of inherent value, especially in situations involving competing sources of sound or noise. The M 201 also compares very favourably with much of its peer group in terms of both linearity and high-frequency response, which implies the prospect of an airier and more accurate sound than may be expected of many such microphones. On loud sources like drum kit and electric guitar, the M 201 may be very profitably employed in any number of configurations. In fact, many instruments in the tenor range should find the M 201 a suitable partner in a studio setting, provided the source is sufficiently energetic and the dynamic mic’s relatively sluggish transient response suits the application. The hum-bucking voice coil also makes the M 201 a useful option where the desired microphone location is close to sources of AC interference.

It should be borne in mind, however, that the microphone will exhibit considerable proximity effect even at distances of 10cm, so its utility in capturing near-field sources will naturally depend on the desirability of enhanced bass frequencies or on the user’s capacity to control or mitigate them. In live settings, where nearness to the source is more or less prescribed, a microphone less prone to proximity effect may (or may not) be preferred. That said, while the M 201’s sensitivity rating is well within industry norms for dynamic microphones, it will still require ample preamplifier gain to deliver useful signal levels on quiet or distant sources, the application of which may expose the signal chain to excessive background noise. Where a satisfying balance cannot be struck between these two limitations a different class of microphone may be deemed more appropriate.

The M 201 is a high-quality example of an unusual class of product, and as such it’s easy to recommend either when chosen for its sonic characteristics as an alternative to more familiar dynamic cardioids or for those of its polar pattern, as long as the limitations inherent to moving-coil technology are properly accounted for.

Andrew Thompson

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