How to select the center frequency and filter type for 5-band digital audio equalizer? I have a small team project: use Matlab implement a Gui 5-band digital equalizer using FIR and IIR filters (2 cases) - The sample rate of all audio files is standard audio 44.1kHz. Coding is not my concern, however, I have 2 questions

(1) What are 5 center frequencies that I should choose ?
I saw a homework problems select 500Hz, 1.5Hz, 4Kz, 10kHZ, and 16KHz but I am not sure how the author came up with these number.

(2) Should I use 5 bandpass filters? Or should I use 1 lowpass, 3 bandpass, and 1 highpass filter?
The answer may depend on your application. I suggest you look at some commercial audio equipments with EQs to decide for those band frequencies. For example the old analog philips casette-type stereo system in my room has 5 band graph equalizers with the frequencies: [100-300-1000-4000-10000] Hz respectively. I use it as an amplifier for my laptop :)

If you design the first and last bands as Bass/treble shelve types, be careful to limit their cutoffs so that mid bands will have enough spectral intervals.