Okay, I'm playing it on Acer Aspire One 522 netbook - while it's not a gaming computer, it's ideal for many older games. The GOG version of GK2 installed and ran just fine, even the subtitles patch works, but I get stuttering sound. Not just music, everything.
Halp?

Try changing to these settings in dosboxGK2.conf.

[mixer]
nosound=false
rate=44100
blocksize=1024
prebuffer=50

[sblaster]
sbtype=sb16
sbbase=220
irq=7
dma=1
hdma=5
sbmixer=true
oplmode=auto
oplemu=default
oplrate=44100

Tried it, didn't help :( Thanks for the advice though

Go to the game folder and run "Graphics mode setup." Change the output to overlay or surface.

You can try the following modifications of the dosboxGK2.conf:

[cpu]
core=normal
cycles=max

I had the same problem as claven (same computer in fact), and the two suggestions solved the problem.

First I tried as Onkel_Donald said to switch "cycles" value to "max": there was much less stuttering. Then I added the part under [mixer] from Vagabond tip, and there is no stuttering at all now.

So, thank you guys! Problem solved.