Audio signal processing unit and audio transmission system, in particular a microphone system

An audio signal processing unit comprising:

• a first receiving unit configured to receive at least a pilot tone signal and a first audio signal from a first audio signal source comprising a wireless microphone;
• a second receiving unit configured to receive at least a second audio signal, which is different from the first audio signal, from an external second audio signal source by way of an audio signal input;
• a pilot tone signal unit configured to:
• obtain the pilot tone signal;
• output a control signal in a first state by way of an output of the audio signal processing unit if the pilot tone signal is received;
• and
• output the control signal in a second state by way of the output of the audio signal processing unit if the pilot tone signal is not received;
• and
• a processing unit configured to process the at least second audio signal depending on the state of the control signal, so that;
• when the control signal in the first state is outputted by the pilot tone signal unit, the processing unit amplifies or attenuates the at least second audio signal with a first level;
• and
• when the control signal in a second state is outputted by the pilot tone signal unit, the processing unit amplifies or attenuates the at least second audio signal with a second level that is different from the first level.

An audio signal processing method comprising:

• receiving at least a pilot tone signal and a first audio signal from a first audio signal source comprising a wireless microphone;
• receiving at least a second audio signal, which is different from the first audio signal, from an external second audio signal source;
• and
• processing the at least second audio signal depending on a state of a control signal, which indicates the presence or the absence of the pilot tone signal;
• wherein, when the pilot tone signal is present, the second audio signal is amplified or attenuated with a first level;
• and
• wherein, when the pilot tone signal is absent, the second audio signal is amplified or attenuated with a second level that is different from the first level.