The audio cassette and compact disc have been with us for many years, and both are still used in many homes even after the proliferation of portable MP3 players. If you assume that CDs always produce higher-quality audio than cassettes, the truth may surprise you.
Cassettes are able to produce a much higher range of frequencies than CDs. While CDs are only able to reproduce frequencies up to about 22 kHz, a cassette can reproduce a dog whistle. Some believe this gives analogue recordings a "fuller" sound. Unfortunately, the hiss produced by low-quality cassette decks can outweigh the additional frequency response, leading many to prefer CDs. Additionally, CDs have a greater dynamic range, and are able to reproduce louder sounds.
To find the best-sounding version of an album, the original recording technology must be taken into account. There is little benefit to buying a cassette copy of an album that was recorded digitally, but a cassette copy of an album recorded on analogue tape may sound better to some.
When a CD is played, it is read by a laser; nothing touches it. Thus, a CD stored properly will not degrade over time. A cassette comes into direct contact with a magnetic playback head, which will eventually cause it to wear out.
When a CD is copied to another CD, the new recording is exactly the same. When a copy of any recording is made using a cassette, a hissing noise will be added and the audio signal on the copy will not be as strong as that of the original.
High-quality cassette players are expensive and must be maintained. The heads must be cleaned and demagnetised periodically or playback quality will suffer. CD players have a clear advantage here: an average CD player will sound nearly as good as a very good one when connected to the same pair of speakers, so many opt for less-expensive CD players. When they fail, they are simply thrown away.