I'm trying to split an audio signal into 5 channels, letting 5 different ranges through each filter (low, mids, highs, etc..). What I'm finding is that each bandpass filter has different levels of attenuation, which I don't understand.
I expect there to be some attenuation, but my "passed" frequencies for some of the filters are at best -6dB. This doesn't make sense to me because shouldnt the corner frequencies be defined as -3dB and they bandpass should allow signals through between these at an attenuation of less than -3dB.
I don't know much about filter design but I chose my capacitor value to be 0.1uF and used the following the following equations to solve for a resistor value to match the cutoff frequencies I want.
Wc1 = 1 / (2piRC)
Wc2 = 1 / (2piRC)
I did this for each bandpass filter diving the ranges of 20Hz - 20kHz into five regions. Perhaps the design I'm using itself is a flawed design? I've looked around a bit and see that a lot of designs include some sort of amplifier between the low pass and high pass portion of the bandpass, could this be the reason?