The MacBook 2,1 has a 2.1 audio speakers (Left & Right speakers, and a Base).
By default the speakers are not setup properly, so the audio unbalanced. This guide will help setup a new audio profile for the speakers so the audio will sound properly.

Edit ALSA cofig file and add the new profile

sudo gedit /usr/share/pulseaudio/alsa-mixer/profile-sets/extra-hdmi.conf

Find the following code in the config file

[Mapping analog-stereo]

device-strings = front:%f hw:%f

<omitted code>

priority = 10

Add the following section after the code above

[Mapping analog-surround-21]

device-strings = surround40:%f

channel-map = front-left,front-right,lfe,lfe

paths-output = analog-output analog-output-speaker analog-output-desktop-speaker

priority = 7

direction = output

Restart the audio (the first part kills pulseaudio, the second reloads ALSA)

pulseaudio -k && sudo alsa force-reload

Next you need to switch to the 2.1 audio profile, you can do this by clicking on the audio indicator in the top right, then “Sound Settings...”. In the new window look for “Mode:” setting and click on the dropdown, then click on “Analog Surround 2.1 Output”.