GRUB_INIT_TUNE="1000 334 1 334 1 0 1 334 1 0 1 261 1 334 1 0 1 392 2 0 4 196 2"
GRUB_INIT_TUNE="600 988 1 1319 8"
GRUB_INIT_TUNE="1750 523 1 392 1 523 1 659 1 784 1 1047 1 784 1 415 1 523 1 622 1 831 1 622 1 831 1 1046 1 1244 1 1661 1 1244 1 466 1 587 1 698 1 932 1 1195 1 1397 1 1865 1 1397 1"
GRUB_INIT_TUNE="220 900 2 1000 2 800 2 400 2 600 3"
GRUB_INIT_TUNE="480 420 1 400 1 420 1 400 1 420 1 315 1 370 1 335 1 282 3 180 1 215 1 282 1 315 3 213 1 262 1 315 1 335 3 213 1 420 1 400 1 420 1 400 1 420 1 315 1 370 1 335 1 282 3 180 1 215 1 282 1 315 3 213 1 330 1 315 1 282 3"
GRUB_INIT_TUNE="480 440 4 440 4 440 4 349 3 523 1 440 4 349 3 523 1 440 8 659 4 659 4 659 4 698 3 523 1 415 4 349 3 523 1 440 8"
GRUB_INIT_TUNE="300 131 1 196 1 196 1 196 1 294 1 196 1 294 1 196 1 131 1"
GRUB_INIT_TUNE="180 440 1 554 1 659 1"
GRUB_INIT_TUNE="2400 587 18 554 4 587 8 659 12 587 16 0 10 587 4 659 4 740 8 587 4 784 12 740 8 659 8 587 4 740 20 587 40"
Based on the previous tune, I've done some variations that are shorter:
The beginning of the Duke Nukem 3D theme, lasting 5.3 seconds (essentially, the first half of the previous comment).
The first two parts of the Duke Nukem 3D theme, 12 notes, 2 seconds:
Only the first part of the Duke Nukem 3D theme, 6 notes, 1 second:
Shameless plug: I've curated some short tunes in a comment in the middle of this Gist. Why short tunes? Because playing these pc-speaker tunes blocks the boot process, and I don't want a computer taking considerably longer booting for this reason.