Shure 545SD-LC Cardioid Dynamic Microphone - Classic Unidyne

Our review of the Shure 545SD-LC finds a rugged, no-nonsense instrument microphone aimed at musicians and live-sound technicians who want a proven tonal character and reliable operation. The single biggest reason to consider the 545SD is its exceptionally uniform cardioid pattern, which keeps close-miking focused and reduces feedback in live and loud stage situations. Shipped for low-impedance use and fitted with a silent magnetic reed on/off switch, this microphone is clearly built for instrument pickup, lectern work, and recording environments where dependability matters.

Key Features

• Cardioid pattern: The exceptionally uniform cardioid polar pattern keeps instrument and vocal pickup focused while minimizing stage feedback for live use.
• Dual-impedance operation: Selectable high or low Z lets the user match the mic to consoles and preamps for flexible use on stage or in the studio.
• Silent on/off switch: The magnetic reed switch offers quiet operation and a lock option so the mic can be muted without handling noise.
• Classic Unidyne design: As the predecessor to the SM57, the 545SD delivers the tonal characteristics favored for instrument recording and pickup.
• Built for durability: The microphone is constructed to withstand regular gigging and handling, making it a solid long-term choice for musicians.
• Included clip: Ships with the Shure A25D microphone clip for secure mounting on stands and instrument rigs.

Who It's For

The 545SD suits working musicians, live sound engineers, and small-studio recordists who need a reliable instrument mic with a classic Unidyne voice and robust build. It is especially appealing for guitar amps, snares, and lectern use where feedback rejection and focused pickup are priorities.

Those seeking modern condenser sensitivity, ultra-low self-noise for quiet vocal overdubs, or features like onboard EQ or digital connectivity should look elsewhere; the 545SD is a dynamic, rugged instrument microphone rather than a studio condenser for pristine vocal detail.

Pros & Cons

Pros

• Reliable, time-tested cardioid pattern that reduces feedback on stage.
• Selectable dual-impedance operation provides flexibility with different systems.
• Durable construction and an included A25D clip make it gig-ready out of the box.
• Silent magnetic on/off switch adds practical control without handling noise.

Cons

• Being a dynamic instrument mic, it has higher self-noise and less sensitivity than condensers for very quiet studio vocal work.
• Some users report mixed impressions of noise level depending on setup and gain staging.

Specifications

Model	545SD-LC
Type	Cardioid dynamic (Classic Unidyne)
Impedance	Selectable high or low Z (shipped low)
Switch	Silent magnetic reed on/off with lock option
Included accessory	Shure A25D microphone clip
Primary use	Instrument pickup, recording, lectern and public address

Our Verdict

The Shure 545SD-LC remains a practical, value-oriented choice for players and live engineers who want the classic Unidyne sound and robust, feedback-resistant cardioid pickup. It is a good investment for instrument miking and PA lectern work where durability and simplicity matter, offering clear value compared with modern specialty mics.

Frequently Asked Questions

Can this microphone be used for guitar cabinets?
Yes. The 545SD's cardioid pattern and tonal character make it well suited to close-miking guitar amps and other instruments.

Is the on/off switch noisy?
No. The microphone uses a magnetic reed switch designed for silent operation and it also offers a lock option to prevent accidental switching.

Does it require phantom power?
No. The 545SD is a dynamic microphone and does not need phantom power; it is shipped set for low-impedance operation.