Barrier Miking is a method of placing a microphone parallel and very close to a reflective surface to ensure that the direct sound and reflected sound reach the microphone at the same time. This is to prevent phase cancellation issues that can occur when the direct sound arrives before the reflected sound. This technique may also be called boundary miking or pressure zone recording. Boundary microphones and PZMs (Pressure Zone Microphones) are constructed around the acoustic principle of barrier miking as devices that limit the amount of interference between direct sound and reflections. These microphones are sometimes favored for piano and drum recording.