In my Acer Aspire 5 notebook with an Intel processor, the internal laptop speakers work great, but when I connect larger speakers via audio jack
connect there's no sound and the loudspeakers rustle.
Can someone send me a solution, for example a Kext or something?
The jack output is intended for high-impedance loudspeakers such as headphones.
If you want to drive external speakers through it, you need a separate amplifier.
But when I got Windows on it, it worked
That can't have anything to do with the software.
What kind of speakers do you want to connect?