A direct method that uses a random optimization process is proposed for the design of parametric IIR (infinite impulse response) filters for audio equalization. The method uses the loudspeaker response as starting point in order to obtain the desired electro-acoustical target. The algorithm uses a bank of parametric second order filters, known as peak filters in the audio field, to equalize and approximate the filtered response to the desired one. When the recursive process is finished, the parameters that define the filters (frequency, gain and Q) are obtained in correction order of importance; first the ones that provide deep correction in the response. This characteristic allows the implementation of scalable systems with different degrees of complexity and correction.