Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to passband bandwidth or baseband bandwidth. Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. Baseband bandwidth applies to a low-pass filter or baseband signal; the bandwidth is equal to its upper cutoff frequency. Uses — In sound recording, equalization is used to modify an instrument's a recording studio in addition to its use in live sound reinforcement for a narrow bandwidth (high Q), most other frequency components will not be affected. The original music is passed through a particular filter to alter its frequency .
