[PD] 6 band eq

[Star Morin]

howdy - 

i'm working on a 6 band eq, and was wondering if folks have any
recommendations on a problem i'm having with it.

i use noise~ as the sound source, through 6 bp~'s (with frequency
ranging from 60hz to 12k) through 6 *~'s w/ a range of 0-2. all of the
"Q"s set to 20.

my problem is that 2 of my middle(ish) frequency bp~'s (800hz and 1k)
are creating a distinctly noted sound... why is this?  what would be
considered "best practices" in creating a multi-band equalizer (q and
frequency ranges, etc) in pd? 

thanks!