Audio Cassette Facts

The popularity of audiocassettes may be on the decline, but they can still be found in over 90% of US homes. Here are some key facts:

A) There are four categories of audiocassettes:

Type I Normal Bias (Ferric Oxide)

Type II High Bias (High Position, CR02, Chrome)

Type III Ferric/Chrome (discontinued)

Type IV Metal (recently discontinued)

B) There are three thicknesses of tape, to accommodate different recording times:

Cassettes from 1 minute to about 74 minutes contain tape that is 18 microns in thickness.

Cassettes from 74 minutes to 110 minutes contain tape that is 12 microns in thickness

Cassettes from 111 minutes to 120 minutes contain tape that is 10 microns in thickness

C) The total time of a cassette is measured by the recording time on both sides. A C-90, for example, is 45 minutes per side; C-60, 30 minutes per side; and so on.

D) No audiocassettes record over 120 minutes in length (60 minutes per side).

E) The longer the recording time (see "A" above), the thinner the ribbon of tape inside the shell, thus the less durable and more susceptible to damage.

F) The shell, by itself, is called a C-0 (C-0 means "zero" amount of record time).

G) The plastic case (box) containing the cassette is often called a "Norelco Box."

F) The paper card inside the Norelco Box is called a J-Card (deriving its name from the "J" shape in which it’s folded to fit in the box).

G) A bulk audiocassette does not contain a Norelco Box or J-Card, just the cassette itself (sometimes called "CN" for "Completely Naked")