Boundary microphones are many a sound tech's secret weapon. Unlike standard condenser microphones, boundary microphones can be lain out flat or secured to a wall or ceiling for the acoustic benefits.
How Do Boundary Condenser Microphones Work?
Technically speaking, boundary microphones - also called pressure-zone microphones (PZM) - work just like any other condenser microphone. The difference has to do with the housing, which is flat in the case of boundary microphones so they can be placed on desks, tables and floors - no microphone stand needed. Besides a practical upside, there's an acoustic advantage as well: by placing the microphone on a table, any sound and echoes in the room reach the microphone at virtually the same time. As a result, unwanted reverb as well as 'comb-filtered' sound is countered. The comb-filter effect occurs when any direct sound is mixed with reflected sound arriving at the microphone a moment later. This leads to certain frequencies getting boosted while others are toned down, resulting in a hollow sound.
Miking Up a Piano or Grand Piano With a Boundary Microphone
Due to their humble dimensions and flat-bottomed design, boundary microphones are perfect for recording or amplifying a gr
