A Pop Filter is used with a microphone to eliminate particular sounds. When saying words with hard consonants, the mouth can cause a sudden air rush, similar to a popping sound. Saying the word 'Pop' out loud will demonstrate the effect. The first 'P' in 'Pop' can overload a microphone for a short duration. A Pop Filter prevents this effect. A Pop Filter can be constructed from many materials and set up in different configurations, but most studios use a round nylon or plastic frame with a mesh placed in front of the mike, between the mike and the singer.

                                X
                 ______         X
   +-------------      |        X             Singer
   |            |      |/_____  X /_________
   |            |      |\       X \  Sound
   +-------------______|        X 
                                X   
     Microphone                 X
                            Pop Filter

Normal sound passes through the mesh, and the sudden popping sounds are dispersed. Some folks mistakenly think the Pop Filter is a spit guard, but this is a secondary role for the device. Pop Filters should be cleaned regularly.