Click here to purchase the entire book in PDF format. Semi-parametric equalizer A less expensive variation on the true parametric equalizer is the semi-parametric equalizer or quasi-parametric equalizer. From the front panel, this device appears to be identical to its bigger cousin, however, there is a significant difference between the two. Whereas in a true parametric equalizer, the three parameters are independent, in a semi-parametric equalizer, they are not. As a result, changing the value of one parameter will cause at least one, if not both, of the other two parameters to change unexpectedly. As a result, although these devices are less expensive than a true parametric, they are less trustworthy and therefore less functional in real working situations.