The first magnetic tapes used to record audio emerged in the 1930s, and by the late ‘40s reel-to-reel machines were found in virtually all recording studios and many homes. The advantages of tape were many, but the large, clunky recording machines and reels of tape that had to be threaded by hand each time they were played were rather inconvenient, and the machines and media were expensive. In 1963 the Dutch company Royal Philips introduced the compact cassette; a miniature reel-to-reel system permanently housed in a sleek plastic shell. The first cassette machines were mono and mostly suitable for voice recordings, but soon the format was improved to allow high fidelity stereo recording and playback. By the early 1970s commercial albums were released on cassette and vinyl simultaneously.
Today, many millions of cassettes are still in existence, and people often take them out of storage only to discover that their old playback machines no longer work. This is not such a big deal for common commercial releases that also exist on CD and downloadable mp3 files; digital versions are already out there and can be obtained easily. But for more obscure custom recordings such as your high school chorus, or completely unique recordings such as a family member talking or singing, the precious audio needs to be rescued and digitized. This usually involves more than just playing the tape on a working machine. Cassettes, because of their small size (1/8” width) and slow playback speed (1.75” per second) are more prone to anomalies like azimuth misalignment, wow and flutter than their larger, more stable reel-to-reel relatives. There are also various types of noise reduction (Dolby B, Dolby C, dbx Type II) that must be identified and properly decoded. The tape path should be cleaned and lubricated often, the heads should be cleaned and demagnetized regularly, and the azimuth should be checked and adjusted for each tape. Cassette tape is also very thin and fragile, and can easily become broken, tangled and/or chewed due to a dirty playback machine or a warped or worn-out tape shell. The small felt pressure pads often come off after years of storage, and the leader tape frequently separates from the magnetic tape due to dried-up adhesive at the original splice, leaving the tape “stranded” in the shell.
Broken, damaged cassettes can usually be repaired, but because of their size and fragility it can be tedious work to untangle and splice them, and frequently the little tape reels (pancakes) must be removed from their original shell and installed in a new one. Once this has been done however, the tape can be played and the audio saved to a digital format where further enhancement is possible.
Throughout the 1980’s cassettes were also used for consumer-grade multitrack recording, offering 4-track and even 8-track capability. Proprietary machines such as the Tascam 234 and 424, the Yamaha MTX8 and the Fostex X18 (to name just a few) must be found in working condition in order to play these back properly.