Portable systems

Portable hi-fi systems operate from the sets of dry cells or rechargeable cells and can need anything from 1.5 V to 12 V. The well-known portable hi-fi set is the so-called headphone radio. There are several designs. Some include only an FM radio; some have AM/FM reception capability. Some have a small box with a cord which runs to the headset; others are totally contained within headset. There are portable CD players which allow private hi-fi listening by headsets. The sound quality from these systems can be excellent. The most significant factor is the quality of the headset.

Another form of portable hi-fi set is called as a boom box. It can produce several watts of audio output, and delivers sound to a pair of speakers built into box. A characteristic boom box is around 8 in high by 18 in wide by 6 in deep. It includes an AM/FM radio and a cassette tape player; some have CD players. The system gets its name from amazingly loud bass acoustic energy peaks its speakers can deliver.