Level 4-1 is the song from Super Noah's Ark 3D. The song is the same for both the DOS and SNES releases, but the different audio hardware plays them each with a distinct sound.
Super Noah's Ark 3D (SNES)
You will hear Level 4-1 song as soon as you start the first floor of the fourth level (see the screenshot), but overall you can hear it on Level 4-1, Level 5-3 and Level 6-5.
The song is output to S-SMP chip.
Super Noah's Ark 3D (DOS)
In the DOS version, Level 4-1 plays in the same stages as in the Nintendo (E4M1, E5M3, and E6M5)