545SD
microphone
$149
Used market: $115*
Specifications
4 of 6 values have a recorded sourceExpert Audio Engineering Commentary
Tonal Profile
The Unidyne III cartridge the SM57 was built from, still sold in its own chrome body with a magnetic reed on/off switch. Same family of sound, no pneumatic shock mount, and a grille Shure lists as a shared part with the SM57.
Gain Staging Advice
Two published sensitivities, not one, because the microphone is dual-impedance: -58.0 dBV/Pa wired low (as shipped) and -35.0 dBV/Pa wired high. We store the low-impedance figure, which is the microphone as it leaves the box and the only wiring that belongs on a balanced input. The 23 dB between them is not free gain - the high-impedance setting is a step-up inside the connector, and it buys level at the cost of cable length and top end.
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.
«Impedance: Dual. Microphone rating impedance is 150 ohms (250 ohms actual) for connection to microphone inputs rated at 19 to 300 ohms and 'High' for connection to high-impedance microphone inputs.»
The 545SD user guide names three impedances for one microphone - a 150 ohm rating, 250 ohms actual, and an unnumbered 'High' - while the specification block on Shure's own product page (www.shure.com/en-US/products/microphones/545sd) for the same model carries a single figure of 100. No two of these agree, so we leave output impedance empty rather than pick one.
checked 8/5/2026* Estimated with the depreciation fallback (~77% retained value). · checked on 8/5/2026