Modulating hiss refers to noise levels that noticeably rise and fall with program level. For example, a common occurrence of modulating hiss can be heard when noise levels rise around each spoken word of dialogue in a soundtrack.
All recorded media are designed to play back at specific, stable rates of speed. If the record or playback speed fluctuates, random variations in the pitch of the program, called wow, will result. Wow is inherent in any mechanical transfer, though in an optimal transfer, it should be so minor as
Magnetic tape or film stores audio information via metal particles applied to one side of the tape or film. A record head applies a magnetic flux to those particles, which then orient themselves to represent the audio information. A playback head reads the magnetic flux stored on the tape to