The Heil PR77D is a professional quality dynamic microphone for use in commercial broadcast, podcasting, and studio or home recording. It is perfect for any application that requires a smooth, flat response over a wide frequency range, excellent transient response, great speech articulation, and low intermodulation distortion (IMD). The PR77D achieves its exceptional performance via a large, 1-inch, low-mass voice coil encompassed by a powerful magnet structure using a mixture of neodymium, iron, and boron. Special attention has been paid to the phasing plug assembly to provide exceptional 180-degree, off-axis rear rejection of over -40 dB. Simultaneously, the front pattern allows the user to move about freely in front of the element with no change in response. Unique to the PR77D is a two-position switch allowing the user to select optimal response frequency characteristics between Voice and Music applications. The Voice position rolls the audio off at 120Hz at -6 dB per octave, whereas the Music position removes the filter and uses the entire audio spectrum of 60Hz to 16kHz. The PR77D is designed to be used exclusively with booms or bases and has standard 5/8 inch. - 27 microphone stand threads.