An audio system , comprising: a headset , comprising: a housing configured for forming a cavity (CAV) along with an external auditory canal (CAN) of an ear (RE, LE) when the headset being mounted on the ear (RE, LE); a speaker disposed in the housing ; and a microphone disposed in the housing ; and a control device , coupled to the headset , wherein the control device is operable to: provide (S302) a reference audio signal to the speaker to be broadcasted toward the cavity (CAV); receive (S304) a sampled sound signal through the microphone from the cavity (CAV) corresponding to a reflection of the reference audio signal; calculate (S306) an acoustic intensity distribution curve over frequencies from the sampled sound signal; and determine whether the cavity (CAV) has a leakage outlet according to the acoustic intensity distribution curve over frequencies; wherein the reference audio signal has a consistent level of acoustic intensity over frequencies; characterized in that the control device is further operable to: extract (S308) a portion of the acoustic intensity distribution curve under a reference frequency; map (S310) the portion of the acoustic intensity distribution curve to an approximate quadratic curve; and determine (S312) whether the cavity (CAV) has the leakage outlet based on at least one coefficient of the approximate quadratic curve. a headset , comprising: a housing configured for forming a cavity (CAV) along with an external auditory canal (CAN) of an ear (RE, LE) when the headset being mounted on the ear (RE, LE); a speaker disposed in the housing ; and a microphone disposed in the housing ; and a housing configured for forming a cavity (CAV) along with an external auditory canal (CAN) of an ear (RE, LE) when the headset being mounted on the ear (RE, LE); a speaker disposed in the housing ; and a microphone disposed in the housing ; and a control device , coupled to the headset , wherein the control device is operable to: provide (S302) a reference audio signal to the speaker to be broadcasted toward the cavity (CAV); receive (S304) a sampled sound signal through the microphone from the cavity (CAV) corresponding to a reflection of the reference audio signal; calculate (S306) an acoustic intensity distribution curve over frequencies from the sampled sound signal; and determine whether the cavity (CAV) has a leakage outlet according to the acoustic intensity distribution curve over frequencies; provide (S302) a reference audio signal to the speaker to be broadcasted toward the cavity (CAV); receive (S304) a sampled sound signal through the microphone from the cavity (CAV) corresponding to a reflection of the reference audio signal; calculate (S306) an acoustic intensity distribution curve over frequencies from the sampled sound signal; and determine whether the cavity (CAV) has a leakage outlet according to the acoustic intensity distribution curve over frequencies; wherein the reference audio signal has a consistent level of acoustic intensity over frequencies; characterized in that the control device is further operable to: extract (S308) a portion of the acoustic intensity distribution curve under a reference frequency; map (S310) the portion of the acoustic intensity distribution curve to an approximate quadratic curve; and determine (S312) whether the cavity (CAV) has the leakage outlet based on at least one coefficient of the approximate quadratic curve. extract (S308) a portion of the acoustic intensity distribution curve under a reference frequency; map (S310) the portion of the acoustic intensity distribution curve to an approximate quadratic curve; and determine (S312) whether the cavity (CAV) has the leakage outlet based on at least one coefficient of the approximate quadratic curve. <EOS>