Frequency response is a specification used in amplifiers, pre-amplifiers, CD players, tape decks and other audio components to measure how uniformly it reproduces sounds from the lowest tones to the highest. An amplifier or other component should preserve the loudness relationship between various instruments and voices and should not over or under-emphasize any frequency or tone. This is known as flat frequency response.
How is it Expressed?
Frequency response is usually measured within the range of human hearing, from a low of 20Hz to a high of 20kHz, although some believe that frequencies above and below this range, known as wideband frequency response are equally important. Frequency response specifications indicate how well the device remains uniform. For example, a frequency response specification of 20Hz-20kHz +/- 3dB indicates that the maximum variation in level or volume from the lowest to the highest tone will not exceed three decibels. A range of three dB is common in frequency response specifications.
Why is it Important?
Uniform or flat frequency response is important because every instrument or voice should be heard as originally recorded. The delicate sound of a triangle should be heard as well as the crash of a cymbal. The amplifier or other device should not raise or lower the level of any sound from the original recording.