Beyerdynamic MM1 Omnidirectional Measurement Microphone

Beyerdynamic MM1

The Beyerdynamic MM 1, also written MM1, is a measurement microphone: a precision tool for analysing rooms, loudspeakers and PA systems rather than for recording music. Its back-electret condenser capsule is omnidirectional and diffuse-field calibrated, each unit is checked by hand, and the slim tubular body is shaped to disturb the sound field as little as possible. Paired with an audio interface and analysis software, it turns guesswork about equalisation and speaker placement into measured data.

Key features

• Omnidirectional measurement capsule, diffuse-field calibrated
• Linear response: 20 Hz to 20,000 Hz, within 1.5 dB from 50 Hz to 16 kHz
• Calibrated sensitivity of 15 mV/Pa at 1 kHz
• Narrow 9 mm head diameter for minimal sound-field interference
• Each microphone individually measured and checked by hand
• Runs on 12 to 48 V phantom power via balanced XLR
• Made in Germany, 88 g slim metal body

Why measurement needs a different microphone

A recording microphone is voiced to flatter a source. A measurement microphone must do the opposite: report the sound field honestly. The MM 1 is equalised for a linear response in the diffuse field, which is the mixture of direct and reflected sound found in real rooms, and it is linear at 90 degrees incidence. That calibration is why system engineers use it with spectrum analysers and room-correction software to set loudspeaker EQ, align delays and verify sound pressure levels.

Precision you can repeat

Beyerdynamic manufactures the MM 1 to a narrow tolerance, with deviation held within plus or minus 1.5 dB between 50 Hz and 16 kHz, and specialists check the frequency response of every individual microphone by hand. Repeatability is the point of the instrument: measurements taken today, next month or after moving a loudspeaker can be compared directly, because the microphone itself is not the variable in the chain.

Slim body, honest capture

The housing narrows to a 9 mm head on a 133 mm body. A bulky microphone reflects and diffracts high frequencies around itself, which falsifies exactly the range being measured; the MM 1’s narrow tube avoids that pressure build-up, so the reading reflects the room and the loudspeaker rather than the microphone. Its low weight also keeps a microphone stand from oscillating or sagging during long measurement sessions.

Connection and limits

The MM 1 connects by 3-pin XLR, draws about 3.4 mA from a 12 to 48 V phantom supply, and presents a nominal impedance of around 160 ohms to loads of 1,000 ohms or more. Maximum sound pressure level is 122 dB at 1 kHz, comfortably above typical measurement levels, and the signal-to-noise ratio exceeds 57 dB. It is not a vocal microphone — its value is accuracy, not character.

For studio builders, live-sound engineers and installers who tune systems by ear and want to confirm the result with data, the MM 1 is the calibrated reference that makes those measurements trustworthy.