Skywalker Sound's version of the 2-pop. This one is extremely rare and can only be heard on raw audio reels for movies that has the soundtrack designed by the company. Depending on the film, the 2-pop would change or have different variations, based on either period, reel, whether the sound was created from scratch based on every film, or due to it being overlapped by the film's audio of the next reel on some movies. There might be occasions where the 2-pop was used during a movie scene too.
Audio Samples
(Delayed echo variant, as heard in the 70mm reel of The Empire Strikes Back.)
(Fade in variant, as heard from the 1987 Pixar party video, presumably taken from the raw audio reel of Tin Toy, to which the tape begins with a clip of.)
(Harmony version, overlapped by reel 4's audio, heard at the end of reel 3 of the 70mm print of The Empire Strikes Back.)
(Harmony version, overlapped by reel 4's audio, followed by a quick low tone beep, heard at the end of reel 3 of the DTS theatrical CD-ROM of the Special Edition re-release of The Empire Strikes Back.)
(2000s version, as heard at the end of reel 1 on the DTS theatrical CD-ROM of Shrek 2.)
(2000s version, with an extremely inaudible reverb effect 1.5 seconds in, as heard at the start of reel 1 on the DTS theatrical CD-ROM of Transformers (2007).)
(2000s version, with leftover reverb effects for the start of reel 7, as heard at the end of reel 6 on the DTS theatrical CD-ROM of Transformers (2007).)