Sound was one of the first things that went into development after the screenplay was finished. Of the 3,200 sounds created for the film, only 4 were made completely electronically. Instead of using electronic sounds to emphasize the futuristic world of Dune, Villeneuve and the sound team wanted to immerse the audience by making the desert world of Arrakis feel "real" and as familiar as the deserts of Earth.
The sands of Arrakis are unlike the sands of Earth- laced with the hallucinogenic substance called Melange- more widely known as "spice." Spice is essential in the world of Dune as it is essential for space navigation. Spice is in everything on Arrakis; the air, the food, and even in the sand. To audibly differentiate the sands of Dune from our own, the sound team got creative. They would bury Rice Crispies in the sand before recording footsteps, giving the Arrakeen sands a subtle crunch to indicate the precious resource.
The Fremen (the native people of Arrakis) have adapted to the harsh conditions of the desert planet in survival tactics and tradition. The Fremen worship the sandworms, calling them Shai-Hulud which means "old man of the desert" or "the ancient one." Riding a sandworm is a coming-of-age ritual to the Fremen. To summon a worm, the Fremen use a device called a thumper that vibrates into the sand, which attracts the worms. To achieve this sound, the team buried a hydrophone mic (which are usually used underwater) and pounded the sand above it with a rubber mallet.
The Voice is a powerful tool used by the Bene Gesserit to essentially force people to do whatever a Bene Gesserit to do. The sound team aimed to give the Voice the power it deserves. The sound team hired voice actors with grittier, more authoritative-sounding voices. They knew the Voice would change the resonance in someone's voice, so they turned up the bass until the editing room began to rattle. They also used a trick called dub reggae which consists of recording a bass note then recording the playback of the bass note through a speaker. The effect worked to enhance the bass' resonance as well as allowing the audience to literally hear the room shake. The compiling of these elements result in a powerful, resounding effect to the Voice.