Classic Unidyne instrument mic features selectable dual-impedance operation with a silent on/off switch.

from $122.00

Available Options

545SD-LC Cable not included

The predecessor to the SM57, the 545SD Classic Unidyne® Instrument Microphone is a dual-impedance, unidirectional, dynamic microphone.

Shipped connected for low-impedance operation, the 545SD features a silent magnetic reed on/off switch with lock-on option. A favorite for instrument pickup and recording, the 545SD can also be used on lecterns in public address systems.



Microphone Type


Simple, rugged diaphragm/coil. handles extreme volume levels without distortion.

Polar Pattern


Picks up the most sound in front of the microphone and some from the sides. Less susceptible to feedback in high volume environments.

Frequency Response


Smooth, extended response. Tuned to accentuate specific types of instruments or voices.

Form Factor


Model Line


The Unidyne Story (1939 to 2014) Brochure (PDF)
Classic Microphones Product Brochure (PDF)
545SD User Guide (PDF)
  • Exceptionally uniform cardioid pattern minimizes feedback
  • Selectable dual-impedance operation
  • Silent magnetic reed on/off switch with lock option
Frequency Response
50 to 15,000 Hz
Polar Pattern
Cardioid (unidirectional)--uniform with frequency, symmetrical about axis
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. Wired for low impedance as supplied.
Output Level
LOW @ 1,000 Hz: Open Circuit Voltage* -58.0 dB (1.3 mV); HIGH @ 1,000 Hz: Open Circuit Voltage* -35.0 dB (17.6 mV) *0 dB = 1 volt per Pascal (1 Pa = 94 dB SPL)

    A55HM Snap-in "Shock Stopper" Mount

    Shock Stopper Isolation Mount/Swivel Adapter, Half Mount, for SM57, SM58, Beta 57A, Beta 58A, Beta 87A, Beta 87C or any Shure tapered handle mic.

    from $45.00

    A26M Dual Microphone Mount

    Allows two Shure SM57, Beta 57A, or 545 Series microphones to be placed vertically on a standard microphone stand.

    from $83.00

    A25DM A25D Microphone Clip (10 pack)

    10 pack of A25D microphone clips

    from $5.00

    R45 Cartridge for 545 Series and PE54

    Direct replacement cartridge for Shure 545 Series and the PE54 series microphones.

    from $76.00

    S37A Desk Stand

    Desk stand, gray finish, for use with various Shure swivel adapters and shock mounts.

    from $29.00

    A2WS Locking Microphone Windscreen

    Locking Microphone Windscreen reduces unwanted breath and wind noise. For use with Shure SM57 and 545 Series microphones. Available in black and gray.

    from $18.00

    A55M Shock Mount Microphone Clip

    Isolation mount and swivel adapter securely attaches Shure models SM57, SM58, SM86, Beta57A, Beta58A, Beta87A, and Beta87C to standard microphone stands.

    from $25.00

    A25D Microphone Clip

    Break resistant microphone clip that securely mounts the SM58, SM57, SM87A, Beta 87A, Beta 87C and all other microphones with 3/4-inch and larger handles to a standard microphone stand.

    from $6.00