By definition, all commercial records pressed before the introduction of stereo LP records in 1957 were monaural (mono), which means they were only able to output one signal channel to speakers or headphones. The driving force behind these two-channel “stereophonic” LPs—a concept that had been tinkered with since the 1930s—was the idea that recorded music sounds better when each ear is presented with a different element of the overall...Continue Reading