Music Philately- Headphones on Stamps
Headphones area pair of small loudspeakers, or less commonly a single speaker, with a way of holding them close to a user's ears and a means of connecting them to a signal source such as an audio amplifier, radio or CD player. They are also known as stereo phones, headsets or, colloquially cans. The in-ear versions are known as earphones or ear buds. In the context of telecommunication, the term headset is used to de scribe a combination of headphone and microphone used for two-way communication, for example with a telephone. The telephone earpiece was common around the beginning of the 20th century. Headphones developed from the earpiece. Sensitive headphones were the only way to listen to audio signals before amplifiers were developed. Very sensitive headphones such as those manufactured by Brandes around 1919 were commonly used for early radio work. These early headphones used moving iron drivers, either single ended or balanced armature. The requirement for high sensitivity m...