A parade of rock 'n' roll lifers — including Billy Gibbons, Slash, and Lemmy, among many others — turned out to pay tribute to Marshall amps in the upcoming documentary Father of Loud.

The film, which shares its title with a 2003 biography of company founder Jim Marshall, has just posted its first trailer, which you can watch above. Some of the other satisfied customers who contributed include Joe Satriani, Slayer's Kerry King and Zakk Wylde.

Describing Father of Loud as a "full-length rockumentary," the filmmakers write, "The Marshall Amp is one of the most recognized amplifiers in the world. Known for the deep, 'crunch' sound. Together with great international guitar players, we try to figure out how Marshall changed their sound and their perspective on rock 'n' roll."

The film also promises to offer an overview of Jim Marshall's "true rags to riches" tale, which took its fateful turning point when he opened a drum shop in 1960. Quickly establishing himself as a reliable source of quality gear, Marshall caved to his clients' growing demands that he stock guitars and amps — and then, after watching their frustrated attempts to obtain a satisfactory sound, he set about building his own.

Father of Loud is still in production and targeted for a fall 2016 release date; in the meantime, directors Lennart Reijnders and Peter Visscher have set up a website offering news updates, photos and a growing assortment of teaser videos taken from interviews conducted for the film.

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