constant directory horn (loudspeaker) (CD)

A Constant Directory Horn(CD) is a horn loudspeaker in which the sound pressure is the same in the vertical and horizontal directions.

Generally speaking, traditional horn speakers experience a sound pressure drop of about 6 dB/ octave at higher frequencies. This drop starts in the frequency range between 2 kHz and 4 kHz. Equalizers can be used to compensate for this level drop. It is different with the Constant Directory Horn, which uses a special construction with a double horn design.