Stereophonic system having power amplifiers and speakers in a bridge circuit with capacitor connecting junction of speakers to common terminal

Claim 1

In a stereo power amplifying system having a common terminal, first and second loudspeaker means for providing first and second sound signals representative of first and second audio input signals representative of first and second audio input signals and first and second power amplifying means for amplifying the first and second audio input signals respectively, the improvement comprising, means intercoupling said first and second loudspeaker means in series between said first and second power amplifying means, and capacitive means connected between said common terminal and the junction of said first and second loudspeaker means for blocking D.C. while allowing spectral components representative of said first and second audio input signals to pass through said capacitive means to said common terminal through said first and second loudspeaker means respectively above a predetermined crossover frequency determined by the value of said capacitive means and the impedance of said first and second loudspeaker means while preventing D. C. from flowing through said first and second loudspeaker means, said first and second loudspeaker means being intercoupled for radiating acoustical energy in phase of spectral components present in said first and second audio input signals in a frequency range below said crossover frequency in which frequency range the signals provided by said first and second power amplifying means are in phase opposition.