The Electro-Voice Dynamic Cardiline RE45N/D is a professional moving-coil dynamic microphone distinguished by its unique dual-cardioid polar pattern and its specific design for noise-canceling applications. This microphone was engineered to excel in environments with high ambient noise, such as sports fields, industrial settings, press conferences, and outdoor broadcasting, where isolating a primary sound source is critical. The "Cardiline" name refers to its patented transducer technology, which utilizes two diaphragms and voice coils acoustically coupled but electrically out-of-phase. This design creates a polar pattern with a tight, well-defined front pickup lobe for the desired sound and a sharp, deep null at the sides and rear, providing exceptional rejection of off-axis noise and feedback.

The microphone's performance is characterized by its ability to capture clear, intelligible speech from a moderate distance, even in acoustically challenging conditions. Its frequency response is tailored to emphasize the presence range for vocal clarity while rolling off excessive low frequencies that often contain ambient rumble. The dual-diaphragm design also contributes to its high handling noise rejection, making it less susceptible to vibrations transmitted through its stand or mount. The microphone requires no external power, operating as a standard passive dynamic microphone, and it outputs a balanced, low-impedance signal via a standard three-pin XLR connector for compatibility with all professional audio equipment.

Physically, the RE45N/D is built to be rugged and durable, featuring a robust metal grille and housing to protect its internal components. Its design often includes an integrated windscreen to mitigate breath pops and light wind noise. While it can be handheld, it is most commonly used on a stand or boom due to its size and optimized performance as a fixed-position microphone. The Electro-Voice RE45N/D stands as a specialized tool in the audio engineer's arsenal, offering a technologically distinct solution for achieving superior source isolation and noise rejection in situations where conventional cardioid microphones would struggle, making it a historical reference in broadcast and industrial audio.