Just heard way back when Harry was still on board that they plan to
use some instruments already used in Alien soundtrack... so this
is just my assumption
Now, everything is changed
Let me remind you, Shankh , didgeridoo, serpent, Waterphone, all
of these instruments were used in Alien!
Here you can read how Jerry used all these instruments:
QuoteThe score for Alien has some very unusual instrumentation and effects, most of which were
designed to evoke either the alien planet, or the alien "Xenomorph" itself:
-Conch shell: Usually low blowing sound, like a contrabass flute, evoking alien winds and used for outdoor scenes on the alien planet.
-Didgeridoo: Used for when the alien Xenomorph appears.
-Serpent: A wood horn with a brass mouthpiece, used for when the alien Xenomorph appears.
Alien "rattle": First appears about 5 seconds into Hanging On (track 9), I think this is from didgeridoo, but with effects. Sounds like someone blowing their nose sometimes. Also used for when the alien Xenomorph appears.
Echoplex (delay): Echo effect used on strummed violins and basses for scenes inside the derelict alien ship.
Pitch-shifting: Electronic effect used on strummed muted harp and violin for the egg chamber scene, but mostly not heard in the film (probably just too weird).
Aleatoric violins: basically "randomly" playing the highest notes possible on the violin, creating a kind of hissing noise, often bouncing the bow on the string as well.