i am new to pd . so plz help me to create a patch which analyse the audio from a microphone or audio playing with in the system and to send messages from pd to comport according to whether its beat , high , mid, low , etc in the audio ..

i know how to send messages to comport as i wanted.
but i want the control over them according to the audio ..
plz help..

The [fiddle~] object is used to do identify the pitch of an incoming source. It's nutoriously difficult to configure, with lots of variable and creation arguments, but read through the help file thoroughly and it should get you started. Maybe someone else here can give you more specific advice.

There's another object, [bonk~], which identifies attack, and therefore beats, in an incoming stream, without estimating pitch. I'm not sure whether [fiddle~] takes care of beat detection itself, or whether you have to use the two in conjunction.

Let us know your progress and post it up when it's finished--this would be a good project to have on record.

Actually Pd now has [sigmund~] which, if I'm not mistaken, is somewhat better than [fiddle~]. You should check that also.

@LiamG
thanks for the help
is there any ways to get the system audio output as the input to pd..???

@alexandros
i am not familiar to pd more than 4 days ... so please help me with an example patch as per my requirement .. please..???

Check the help patch of the object (right click on it in non-edit mode and click on "help" from the pop-up menu). In its help patch click on [pd sinusoidal-tracking] to see how [sigmund~] can do audio analysis (it gives you the sinusoidal components of its audio input).
Reading your original post, I guess in order to separate frequency bands, you can use Pd's user-friendly filters, [lop~] (for low pass), [bp~] (for band pass), and [hip~] (for high pass). Connect each filter to an [env~] and check its output. The louder the output of [env~] the more frequencies of your signal are present in that area.
Maybe this is an easier way to do what you want (if I got it right) than using [fiddle~] or [sigmund~].
As for how to route audio within your system, on Linux that's pretty easy using Jack. It should work on OS X too. Dunno about Windows.

@alexandros thanks