[PD] 6 band eq

[Star Morin]

ahhh - never mind (except the "best practices" part - i'm still totally
interested in that ;)

i had a bad understanding of "q" (confusing "q" with bandwidth).  i was
set straight by this excellent guide: 
http://www.tonmeister.ca/main/textbook/electroacoustics/01.html

----
An inherent problem in this type of filter is commonly known of as
"ringing." This is "the tendency of a filter to resonate at its natural
frequency when excited by a sine wave pulse at that frequency." This
effect is present to some extent in all equalizers but is of a low
enough level to be masked by the remainder of the signal. It does,
however, become excessive with filters with a high Q. At Q=0.5 the
circuit does not ring and is said to be critically damped. Higher values
of Q, however, will result in ringing for more cycles as the bandwidth
becomes narrower.
----


On Wed, 2004-04-21 at 15:59, Star Morin wrote:
> 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!
> 
> 
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