Compression Driver

Developed by Bell Laboratories in the early 1930’s the compression driver is a special type of dynamic loudspeaker (meaning it works just like a dynamic microphone, but in the opposite direction) designed to fit onto the small end of a horn. The horn acts like an acoustic transformer, with the driver providing a high sound pressure level at throat of the horn, with the mouth of the horn providing a large area of low pressure to radiate the sound efficiently into the air. They work by attaching a voice coil to a diaphragm (much like any tweeter) whose surface radiates sound into the horn through a small opening known as the throat, which is where the compression occurs. There are many sophisticated design variables involved in producing a high quality compression driver.