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

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

Still no luck.

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.