Thanks to the instructions by boomshop found on the Ubuntu Forums I finally have crystal clear sound on my Macbook:

If always had problems (since 7.04) with some static or distorted sound from the left speaker / left headphone on my book. I found serveral solutions on the internet like:

- options in /etc/modprobe.d/alsa-options: only worked out on 7.10, never in 7.04, 8.04, 8.10 for me
- reloading snd-hda-intel on boot with /etc/rc.local: dind’t work since alsa or pulse is already running at that time

…but reloading the module was a fix I found in several tests with different inits.

So a simple solution for me is reloading the module BEFORE anything else sound relevant is started. I’ve done this through rc-inits:

Code:

echo -e '#!/bin/bash\nrmmod snd-hda-intel\nmodprobe snd-hda-intel' | sudo tee /etc/init.d/soundrestart

This one adds a script to init.d wich is only removing and loading the snd-hda-intel module.

Code:

sudo chmod +x /etc/init.d/soundrestart

This line will make the script executable.

Code:

sudo update-rc.d soundrestart start 10 2 3 4 5 .

And the last one will add it to the different inits at a really early stage (10), before hal (24) pulse (25) or anything else is loaded.

Never had any static, distortion or noise in my left output anymore – neither after boot, nor after reboot, wakeup or something.