Before the dawn of the digital age, all recording and mastering was done on large analog recorders onto reels of magnetic tape. Home recording enthusiasts generally used 1/4-inch tape, while professional facilities used 1/2-inch, 1-inch, or 2-inch tape. In 1934, BASF produced the first magnetic recording tape, which used cellulose acetate base tapes coated with ferric oxide. Within a year, AEG had produced an “advanced Magnetophon recorder,” and the first recording of Mozart’s E-flat Symphony performed by the London Philharmonic made in 1936 – which still exists to this day.
The term “reel-to-reel” came from the recording process where a new, blank metal oxide reel of tape was placed on the left side of the recorder and threaded across the heads and between the capstan and then out onto an empty “take-up” reel — the tape moved from reel to reel. Professional recorders evolved to run at speeds up to 30 inches-per-second (ips), though home users typically used slower speeds of 7-1/2 or even 3-3/4 ips.