On my mixing board there states "Bandwidth" under the EQ section and i wanted to know if that was the same as Q which effects how much of the frequency spectrum your affecting, and if so. the numbers 3, 6, etc... what do the numbers correspond with, as it is usually Hz for the sound spectrum.
Bandwidth is not the same as "Q" but it is probably what the maker means. Bandwidth is expressed in a freq range e.g. 707 -- 1414 Hz (one octave with a center freq at 1 kHz), "Q" (quality) is expressed in a value. Q = 1.41 is equal to one octave but the bandwidth will depend on the center frequency since one octave in the lower bass region is only a couple of Hz (20 -- 40 Hz is one octave) compared to an octave in the treble region where it's thousands (8 kHz -- 16 kHz is one octave).
It would depend on how the term bandwidth is used by the manufacturer. Bandwidth can mean the entire frequency response of the mixer or just a small portion of that frequency response. As stated above "Q" usually refers to the "bell" of the alteration you will make. In a graphic EQ the frequencies around a center point that are affected are set by the manufacturer and you can only alter the amount (probably the 3-6- ...) of change. In a parametric EQ you can shift the center frequency, often how wide the bell will be and the amount of gain or cut.
I'm afraid your question doesn't give enough information to give better answers than what you have here.