M3
microphone
$149
Used market: $115*
Specifications
6 of 8 values have a recorded sourceExpert Audio Engineering Commentary
Tonal Profile
Half-inch permanently polarised cardioid in a metal body, with a two-step pad (-10 / -20 dB) and an 80 Hz high-pass, both hidden under the lower body shell. Rated to 142 dB SPL.
Gain Staging Advice
The M3 runs from a 9 V battery as well as from P24 or P48, which is the reason to own one: it works on a mixer whose phantom rail is dead or absent. Sensitivity is where the sheet fights itself - see the published-specification note below - so budget an extra 4 dB of gain headroom rather than trusting the -40 dBV figure exactly. Self noise is 21 dBA, high enough that this is not the microphone for a quiet room tone.
What the datasheet actually says
Quoted verbatim from the manufacturer’s own page, with the date we checked it. We state what is printed, not what anyone intended by it.
«Sensitivity: -40.0dB re 1 Volt/Pascal (6.30mV @ 94 dB SPL) +/- 2 dB @ 1kHz»
The reference is named, which is more than most makers manage, but the two halves of the row are 4 dB apart: 6.30 mV/Pa is -44.0 dBV/Pa, not -40.0. The same pair appears on the product page and again in the M3 product manual, so it is a stable published figure rather than a typing slip on one document. We store the -40.0 that carries the stated reference and flag the 4 dB.
checked 8/5/2026«Maximum Output Level: 9.2mV (@ 1kHz, 1% THD into 1KOhm load)»
The M3 product manual gives the same row as 'Maximum Output: +9.22dBu (@ 1% THD into 1kOhm)'. +9.22 dBu is 2.24 V, roughly 47 dB above 9.2 mV. Taken literally, the web figure would mean the microphone clips below conversational level, which the 142 dB SPL rating on the same page contradicts.
checked 8/5/2026* Estimated with the depreciation fallback (~77% retained value). · checked on 8/5/2026