Tape cartridges are electromechanical devices, and their build quality directly affects the available sound fidelity. In 1969, Olympus released their microcassette format, which features many of the same build specifications as a standard cassette tape, only miniaturized. Most significantly, microcassettes feature a traditional pinch roller to advance the tape inside of its cartridge, providing a stable pitch control mechanism which keeps the audio on the tape in true pitch and avoids fluttering recordings or playback. Microcassettes also feature controlled tape speed, providing clean and consistent recording.
Developed by Norelco, and later Philips, in 1967, the minicassette brought a lower price point to the miniaturized tape format market. These cassettes utilize fewer internal parts in their construction, and do not feature the same drive system as microcassettes. By driving the tape directly by the reels, the minicassette features minimal internal components. This keeps the cost per unit down, but can result in a more fluttering and lower quality audio recording.
Most microcassettes feature a long recording length at 30 to 45 minutes per side by utilizing a wide tape similar to standard cassettes, but with a thinner dimension. Though initially developed for monophonic, voice-only recordings in the dictation and data markets, microcassettes developed the ability to record in stereo for music production by the 1980s. Later advancements brought a "Type IV," or metal formula to the tape itself, providing a huge jump in sound quality and reliability.
Due to its simplified mechanisms and lower price point, minicassette tape systems were developed for voice recording only. To keep with this design philosophy, minicassettes feature a more narrow, thinner tape than microcassettes, which is more prone to wow and flutter, and poor playback performance. Minicassettes are available only in monophonic formats, and provide less audio quality than microcassettes for music and speech.