Crackle sound with external speakers

[dreamsINdigital]

I'm using external speakers on my MacBook. They're the Logitech Z-640 5.1 set, but I'm only using 2.1 with them. I noticed that if the computer isn't playing any sounds for awhile, for the lack of a better word, the speakers make this crackle sound as if the signal to them is turned off. When the computer is about to make a sound, such as when I start to play a song or a sound plays through Adium, it makes the crackle sound again before playing sound. It's as if the signal to the speakers is turned off when idling (no sounds are playing). I hope that makes sense. Does this happen to anyone else? It's kind of annoying. Is there a fix?

Thanks

 

[thebeephaha]

It's the soundcard chipset turning on and off [or just coming out of an idle state] to save power.

 

[dreamsINdigital]

So this is normal? Has anyone else noticed this?