Deep Note

Deep Note is a crescendo used for THX trailers. It was created by James A. Moorer in 1983, who was now an employee of the Lucasfilm Computer Division. The sound is used on trailers for THX-certified movie theatres and video releases. It was first used in the THX trailer shown before the 1983 premiere of "".
Description.
The U.S. trademark registration for the sound contains this description of it:
The Deep Note had originally been from a soft to a loud pitch. Over the years it has been remixed digitally which made the Deep Note with a more abridged sound. Beginning in 1988 the Deep Note became louder and abridged. In 1993 the Deep Note was cut short to save time for Laserdisc (1995 for VHS). Most recently, however, the Deep Note has been cut short to the single note (where both sounds stay in one pitch). This is in favor of other sound effects in certain THX logos.
The sound is perceived as louder than it actually is; sound designer Gary Rydstrom explains that, "from a technical standpoint, 'Deep Note' just feels loud because it has a spectrum of frequencies that grows from small to large."
James A. Moorer has been quoted as saying, "I like to say that the THX sound is the most widely-recognized piece of computer-generated music in the world. This may or may not be true, but it sounds cool!"
Furthermore,
Previous works.
Prior to the creation of Deep Note, several other works made use of similar techniques of frequency spread.
In their book "Analog Days", Trevor Pinch and Frank Trocco point to the track "Spaced", from the 1970 Beaver &amp; Krause album "In a Wild Sanctuary" as the source for Deep Note. They quote synthesizer builder Tom Oberheim as saying the original analog form is much richer than the "digital perfection" used in movie theatres.
Other similar predecessors include:
In popular culture.
The perceived loudness of the Deep Note is frequently depicted as having actual destructive effects: