A method for diagnosing the operating state of a public address system comprising at least one loudspeaker (6, 8, 10) intended to be connected to an audio player and arranged in an at least partly closed space, this method including the following steps: - excitation of the or each loudspeaker (6, 8, 10) using a predetermined test signal (St(t)); - broadcast of acoustic waves representative of said test signal (St(t)) by the or each loudspeaker (6, 8, 10) in said space; - acquisition of a digital response signal (Sr(t)) representative of the acoustic waves broadcast by the or each loudspeaker (6, 8, 10) in said space, by at least one acoustic wave acquisition means; - processing (46, 48, 50) of the digital response signal (Sr(t)); - determination (52, 53, 54) of energy distribution coefficients (ayx, byx, cyx, afyx, bfyx, cfyx, dyx, dfyx) representative of the energy distribution of said digital response signal (Sr(t)), per frequency band; and - comparison (58, 60) of said energy distribution coefficients (ayx, byx, cyx, afyx, bfyx, cfyx, dyx, dfyx) with predefined threshold ranges in order to diagnose the operating state (S, MP, DE, OFF, DEPH) of each loudspeaker (6, 8, 10), characterized in that the test signal (St(t)) comprises a defined number (n) of sequences of a pseudorandom signal, and in that said processing step (46, 48, 50) includes the following steps: - time partitioning of the digital response signal (Sr(t)) into a number of sequences (Ss(t)) equal to the defined number (n) of sequences of the test signal (St(t)); - determination of an averaged sequence (Sm(t)) of the response signal by calculating the point-to-point average of said sequences (Ss(t)) of the partitioned digital response signal; and - determination of a sequence (Si(t)) of the impulse response signal from said averaged sequence (Sm(t)) of the response signal. - excitation of the or each loudspeaker (6, 8, 10) using a predetermined test signal (St(t)); - broadcast of acoustic waves representative of said test signal (St(t)) by the or each loudspeaker (6, 8, 10) in said space; - acquisition of a digital response signal (Sr(t)) representative of the acoustic waves broadcast by the or each loudspeaker (6, 8, 10) in said space, by at least one acoustic wave acquisition means; - processing (46, 48, 50) of the digital response signal (Sr(t)); - determination (52, 53, 54) of energy distribution coefficients (ayx, byx, cyx, afyx, bfyx, cfyx, dyx, dfyx) representative of the energy distribution of said digital response signal (Sr(t)), per frequency band; and - comparison (58, 60) of said energy distribution coefficients (ayx, byx, cyx, afyx, bfyx, cfyx, dyx, dfyx) with predefined threshold ranges in order to diagnose the operating state (S, MP, DE, OFF, DEPH) of each loudspeaker (6, 8, 10), - time partitioning of the digital response signal (Sr(t)) into a number of sequences (Ss(t)) equal to the defined number (n) of sequences of the test signal (St(t)); - determination of an averaged sequence (Sm(t)) of the response signal by calculating the point-to-point average of said sequences (Ss(t)) of the partitioned digital response signal; and - determination of a sequence (Si(t)) of the impulse response signal from said averaged sequence (Sm(t)) of the response signal.