Why is it Important to Perform Frequency Analysis on Audio Signals?

Frequency analysis is performed on audio signals to determine how the signals respond at all of the various frequencies within a certain bandwidth, i.e., what gain these audio signals produce at all the various frequencies.

For example, frequency analysis may be performed on a microphone to determine how it responds to frequencies from 20Hz to 20KHz. A microphone doesn't produce the same levels of gain at all the different frequencies. At some frequencies, it may produce a higher gain. At other frequencies, it may produce lower gain. For example, a microphone may amplify low frequency sounds, bass, well, but not higher frequency sounds, treble. Therefore, it is necessary to do a frequency sweep on a microphone and then perform frequency analysis on the audio signal to see what gains the microphone produces at all the various frequencies.

Why is it important to know how a microphone responds to various frequencies? Because depending on the application that the microphone is used for, frequency response may be critical. If a microphone is being used primarily for voice communication, it's important that it amplfies bass with a high amount of gain, since voice mostly falls in the low frequencies of 180Hz-3400Hz, and less important that it amplifies treble well. However, if a microphone is going to be used for recording music, with a wide range of a variety of lows and highs, it must amplify all frequencies from bass to treble, with high gain.

The same is the case for speakers. Frequency sweeps are done on speakers and then frequency analysis is performed on their output signals to determine what level of gain they produce for sounds of the various frequencies of a bandwidth. Again, depending on the use and application of the speakers, its frequency response may be crucial. Some speakers, such as piezoelectric buzzers only play one frequency, usually a 1.5KHz signal, so it only has to amplify sound at that frequency with a fairly high amount of gain. Other speakers such as those that play out music must provide gain at all the various frequencies from 20Hz to 20KHz in order to play out both bass and treble well. Thus, this is why performing frequency analysis on audio signals is so crucial.