Deep Note

The Deep Note is THX's audio trademark, being a distinctive synthesized crescendo that glissandos from a low rumble to a high pitch. It was created by Dr. James A. Moorer, a former employee of Lucasfilm's Computer Division in late 1982. The sound is used on trailers for THX-certified movie theaters, home video, video games, and car infotainment systems.

The Deep Note debuted at the premiere of Return of the Jedi in Los Angeles. Since then, it has gone on to be a pop culture icon both in meme and cult nature, and had been redesigned and rerecorded for the 2015 "Eclipse" trailer.

The U.S. trademark registration for the first version of the sound contains this description of it:

The THX logo theme consists of 30 voices over seven measures, starting in a narrow range, 200 to 400 Hz, and slowly diverting to preselected pitches encompassing three octaves. The 30 voices begin at pitches between 200 Hz and 400 Hz and arrive at pre-selected pitches spanning three octaves by the fourth measure. The highest pitch is slightly detuned while there are double the number of voices of the lowest two pitches.

The first version of the Deep Note made its debut before the first THX trailer, Wings, that preceded the premiere showing of Return of the Jedi. Two different interpretations of the note ran concurrently with the 1983 version in both the Grand trailer and the mid-90s reorchestration of the Cimarron trailer. The Deep Note originally transitioned from a soft to loud intensity, and over the years has been remixed digitally, as new technology developed. In 1993, the Deep Note was cut short and pitched higher (ending in an E chord rather than a D), to save time for Laserdisc and again in 1995 for VHS. In 1996, with the debut of Tex, the Deep Note was low-pitched and cut short which is different than other versions. It was later used in the DVD version of the digitally mastered variant of the iconic Broadway trailer in 1997, then later with both the Ziegfeld and Tex Action trailers in 2006. In 2007, for the Amazing Life trailer, the Deep Note had been cut short to the single note (where both sounds stay in one pitch), in favor of other sound effects. However, in the last two trailers to use the 1983 note, both based on the famous Broadway trailer, the sound was played in full.

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