MONO is how most listeners first heard Elvis in the 1950s and 1960s, when it was the predominant audio format. Until 1968, each Elvis album was given a unique MONO and STEREO mix, but Elvis always regarded the MONO mix as primary. This was also true for singles. Up until affordable home STEREO systems in the late 1960s, the record industry always regarded STEREO as secondary, going back to its debut in the late 1950s. MONO singles, EPs and LPs were the standard for retail and radio.
The recorded legacy of Elvis Presley continues to be discovered by new generations that never saw him or heard him perform live. It's hard to appreciate that he started so much of what we take for granted now in popular music. Until 1956, the teenagers of suburban America, and the rest of the world, had to endure ditties by Rosemary Clooney and Perry Como but everything was about to be tossed upside down. On January 28 on a cold night in New York, Elvis took America by storm as he appeared on CBS-TV's Stage Show hosted by Jimmy and Tommy Dorsey. On February 4 for his second appearance he sang a song that literally changed the world of popular music "Heartbreak Hotel". Its unique sound and style literally blew everything before it away while at the same time inducing the blueprint for everything that was to come; by April, it would be #1 on Billboard.
The new multi-part documentary Elvis Presley: The Searcher, directed by Thom Zimny and airing on HBO on April 14, pushes past the larger-than-life image of The King of Rock and Roll, portraying him instead as a man and an artist "who wanted to heal, to find that thing that was always felt to be missing, and to do it through the music."