i'm all new to pure data(allready in love and hooked), read some manuals en tutorials for about a week now and this is probably my fourth patch, so maybe i'm doing something really stupid and obvious(hope so).

i'm expiriencing these pops&clicks with everything that changes in the patch. it's hard to discribe for me in english but in this case(but happens with everything) a phasor~ melody is gong into a bpf~ wich centre frequency is randomly changed every 100ms/200 ms(it doesn't matter) now every time the center frequency is changed there is a click or pop coming thru my speakers. some louder than other.
try'd lowering the output volume wit *~ 0.5 for instance but this didn't work.

my delay time is set to 50 ms but even changing it to 500 ms doesn't change a thing.
this happens as well when using my internal soundcard as using my fasttrack pro.
im using pd40.3 extended on a 2.4ghz 2gb ram macbook pro.

patch:
http://www.filefactory.com/file/d63db3/n/random_tone_bp_noise_bpm_pd

Try replacing the instances of [bp~] with [vcf~]. The difference is that [vcf~] takes signals as the center frequency input, as opposed to messages, and is thus more suited to filters with constantly changing values. The tradeoff is that it's a little more CPU-expensive, but you'll be fine. To convert the center frequency values going into [vcf~] to signals, you can use [sig~], but you'll probably be better off using a [line~] to ramp from one value to the next. Between the number box and the [line~] you'll need a message box with "$1 5" or "$1 20" or whatever millisecond ramp length works for you. Like so:

(number)
|
[$1 20(
|
[line~]
|
[vcf~]

thanks alot. changing the [bpf~] to[ vcf~] did the job!
but now i have a total different question (i'm a newbie): the [line~] object is to make smooth linear lines from one to another value right? but what does the message {$1 20( mean? (or [$1 5( or whatever)?

$1 in a message box is a variable, so that makes [line~] ramp to whatever number that the number box puts out. Check out hardoff's extensive explanation here.

And the second value in the message box is the amount of time you want the ramp to take.

Although, now that I read a bit closer, that thread has a lot more information than you need just to understand $ variables in message boxes... I think your question can pretty much be answered in the help files for message boxes and for line~.