The U.S. trademark registration for 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.[2]
Spectogram made using Spek
The Deep Note had originally been from a soft to a loudpitch. Over the years it has been remixeddigitally 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!"[3]
Furthermore,
The score consists of a C program of about 20,000 lines of code. The output of this program is not the sound itself, but is the sequence of parameters that drives the oscillators on the Audio Signal Processor (ASP). That 20,000 lines of code produce about 250,000 lines of statements of the form "set frequency of oscillator X to Y Hertz".[3]
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 & 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:
Iannis Xenakis' piece Metastasis (1955), which contains a very similar effect in the first minute that begins on a single tone and slowly spreads into a quarter tone cluster.
Styx's 1974 song "Krakatoa," which features the spread tone.
Yellow Magic Orchestra's 1981 track "Loom," with an upward slow glissando to crescendo at the beginning.
In popular culture
The perceived loudness of the Deep Note is frequently depicted as having actual destructive effects:
In movies and TV shows
The 1992 made-for-video feature Tiny Toon Adventures: How I Spent My Vacation shows a Deep Note–like trailer blasting a theatre, concluding with the text "THUD: The Audience Is Now Deaf."
In the 1994 Simpsons episode "Burns' Heir," a THX trailer plays before a movie, blowing the audience back, shattering eyeglasses, teeth, and even causing one person's head to explode; despite this, Grampa Simpson shouts, "Turn it up! Turn it up!" This segment was later turned into a THX theatrical trailer.
In the 2006 movie Over the Hedge, Deep Note is featured in a scene late in the movie, when the animals enter a house and the porcupines were trying to setup a camera with a television, but accidentally tune the TV to a movie starting with the sound. The shear force of the sound blows some porcupine quills off.
In the Boondocks episode "...Or Die Trying", Grandpa mimics the "Deep Note" when reassuring Jazmin that the theater they are going to is a quality theater.
In the very beginning of the 2006 movie Tenacious D and the Pick of Destiny, Deep Note is parodied in the beginning by Jack Black and Kyle Gass with cartoon versions of themselves flying via flatulence propulsion, and the words "THC: The Audience is now baked" appear on the screen.
Rapper Dr. Dre was sued in 2000 by Lucasfilm, then-owner of THX, for using an unauthorized cover of "Deep Note" on his album 2001. [4]
Australian grindcore band The Berzerker use the sound in their concerts before they perform the song "Mono Grind."
The "Mega Lo Mania Remix" of Mylène Farmer's song "California" begins with Deep Note.
Rock band Asia used Deep Note as the opening for the song "Countdown to Zero" from their 1985 album Astra.
Homage
A sound similar to Deep Note is included as an easter egg in the BitTorrent client µTorrent.
A sound similar to Deep Note is used in the logo for Tokuma Japan Communications, the home video division of Tokuma Shoten.
Radio host Tom Leykis used Deep Note to "take out" callers, "THX style," until he received a cease and desist notice. [source?]
The LucasArts adventure game The Curse of Monkey Island opens with a large 'CMI' logo with a Deep Note, accompanied with the caption "The Monkeys are Listening"
A parody of the THX logo was shown before Jane Bond: Your files is now mine on Mad TV, on FOX and Comedy Central. The Deep note is parodied, The THX logo is parodied as FHX. The Audience is Listening is parodied as, The Audience is Sneezing.
Tex, and the THX trailer that shares his name, are featured in an easter egg on Duck Dodgers Starring Daffy DuckNintendo 64 release. The trailer was made without the involvement of THX. In this parody, Tex awakes Daffy Duck, who was sleeping in a hammock. He is then chased around the frame, and was smashed before he can "repair" the trailer. Besides, the logo is shown entirely and a lower-pitched version of the "Deep Note" is heard.
