posted 29 July 2002 08:42            

This buzzing sound is most prominent when you use a pull-down menu……and *always* goes away when you hold the button down on your mouse or track pad. With the capybara disconnected from my system the buzzing is still present until you reboot with out the capy connected.

I can't figure out where this buzzing is coming from (disk/lcd?)……but obviously has something to do with the firewire…..the strange part about his is that it goes away when you click and hold the track pad or mouse button….weird. (And no.....its not the fan....but the fan does kick on alot with Kyma!)

I have not observed this behavior with kyma on the icebooks……..

Question:

Would the computer resource ‘problem’ (kyma in the front when streaming) be improved with a SECOND firewire port directly on the capybara for a fast firewire disk or an internal hard drive inside the capybara? (Like the Richmond Sound Design Audiobox?) I also noticed that new Protools 002 thing has 2 firewire ports one for your computer and the other for your FIREWIRE disc.....cool!

posted 29 July 2002 09:33            

One possible explanation: The processor draws differing amounts of current depending upon what program is running. So the processor calls on the switching power supply to supply different amounts of current depending on what program is running. Inside the power supply is a transformer that is switching between electrical and magnetic fields at a rate that can depend on how much current you are drawing from it. When it is in the magnetic phase, it could attract the metal core and move it just a slight amount.
When the program is periodic (and most programs do have loops that run for long periods of time), this movement of the metal core will also be periodic and, depending on the length of the program loop, could repeat at a rate that is in the audible range.
When you hold down the mouse button or menu, the program goes into a very short loop (hence the frequency would go much higher and out of the audible range).
You could test this theory by putting an AM radio (tuned between stations) next to the computer and cranking the volume. You should hear similar changes in the frequency of the RF emmissions from the computer.

Theory number 2: The amplifier in the built-in speaker on the TiBook is demodulating the radio frequency emmissions from the switching power supply. You could test this theory by plugging something into the headphone jack to hear whether the sound goes away or not.

posted 31 July 2002 08:36            

Bingo! This is exactly what is going on. Broke out the Grundig SW and this is exactly what is going on......So I spent the next hour doing Morse Code with my trackpad and the radio

"... --- ... / ... --- ...".
"... --- ... / ... --- ...".
"... --- ... / ... --- ...".

Of course I couldn’t resist mic’ing it + processing it thru the cappy
Who needs sleep?

x0x
r

posted 01 August 2002 11:37            

Then I bought a new tiny 9 inch firewire cable and it went away.

I can't explain