Music Thing: The THX Sound

Each week Tom Whitwell of Music Thing highlights the best of the new music gear that's coming out, as well as noteworthy vintage equipment:

All this week on Music Thing I've been running a series about those tiny bits of sound that everyone recognizes - like the Mac Startup sound and the 'Intel Inside' chimes. The best story of all is about the THX Sound (aka 'Deep Note'), that huge, weird, mess-with-your-head noise that was first played before the premiere of 'Return of the Jedi' in 1983.

It was created by Dr James ?Andy? Moorer (pictured at right), at LucasFilm?s DroidWorks research laboratories. He used a vast, one-off computer called the Audio Signal Processor (ASP), which he used as a digital synth.

The brief for the sound was ?Something that comes out of nowhere and gets really, really big!? To create it, Andy spent four days writing a 20,000 line C program. When that was run, it created 250,000 lines of commands which were fed into the ASP. Those commands controlled the machine?s 30 virtual oscillators and created the 30 second long sound.

Because his C program was full of random numbers, no two ?performances? were ever quite the same. When the original master tape was briefly lost, he tried - and failed - to recreate the sound, but it always sounded slightly different.

Andy believes that the sound is ?the most widely-recognized piece of computer-generated music in the world?, which is probably true. At one point, it was playing 4,000 times a day at cinemas all over the world. That?s once every 20 seconds.

Andy went on work with Steve Jobs at NeXT and consult for Adobe and other companies. Today, he spens his time repairing old tube radios and playing his customised banjo. LucasFilm?s ASP was decommissioned in 1986 and later sold for scrap.