SoundOn! prevents PowerBook G4's (and other Mac models' too) speakers from turning off when you use battery power. In fact, to save energy, Mac OS X turns PB G4's speakers off after a while if no sound is played and you're using battery power.

The negative side of this is that when the computer plays a sound you see the spinning rainbow cursor and have to wait for two or three seconds (while the computer waits for the speakers to be turned on) before you can continue using the computer.

SoundOn! plays a "silence" sound every twenty seconds, so that your PowerBook's speakers will be never turned off and will be ready to play when needed: so you'll stop waiting at every damn sound! :-)

You may say that this will lower the duration of the battery and probably it does, but I can say that battery performance decrease is not noticeable. Another thing... SoundOn! is not needed on Mac OS 9 since this OS doesn't seem to turn off speakers.

Apple posted a kbase article about this issue.The affected models are:

-iBook (Dual USB)
-iBook (Late 2001)
-iBook (14.1 LCD)
-PowerBook G4 (Gigabit Ethernet)
-Power Mac G4 (QuickSilver 2002)
-iMac (Flat Panel)

What's New in This Release:

· The application automatically quits if it is launched under Mac OS X 10.1.1 or lower.
· The silence sound is executed every 20 seconds instead of 10, so that SoundOn uses even less processor time than version 1.0.