Cascading several parametric equalizers provide frequency shaping control of the input signal with three control settings: gain, center frequency, and bandwidth or Q-factor. Parametric equalizers control the tone and sound to flatten or match different input sources during mixing or provide particular effect to the input signal. Equalization usually compensates for the physical response of microphones or speakers, balances the tone of several instruments, or changes the timbre of an instrument since these filers provide very selective frequency adjustment during mixing or a specific range effect during recording. For example, small earbud headphones might not be able to reproduce low.