The Soundworks Collection has released a mini-documentary about how the epic sound of The Hobbit: An Unexpected Journey was created. From begininning to end, Peter Jackson's team used more advanced tech than on the original Lord of the Rings Trilogy.
Despite having three films worth of Middle Earth sound to draw on, basically everything for the new films was re-recorded on location in New Zealand. That means all of those cave sounds you hear throughout the film were actually painstakingly recorded in caves. The problem is that existing library from The Lord of the Rings Trilogy was all recorded at 16-bit/44.1 kHz, and the sound designers wanted to capture everything in high-definition, 24-bit/48 kHz.
Beyond entirely new source material, The Hobbit's mixers had access to Dolby Atmos this time around. The new theatrical sound system allows designers to plot sound elements to individual speakers around and above the theater. Compared to a simpler 5.1 surround sound design, Atmos allows designers to create more immersive sounds. So when Peter Jackson wants a battle to sound like a nightmare—it does. [Soundworks Collection]