A system for increasing the privacy of telephone conversations carried out on board of a motor vehicle, comprising at least: - an electronic control unit suitable to be mounted on board of the motor vehicle; - a plurality of sound sources suitable to be mounted on board the motor vehicle in predefined positions and suitable for emitting sound waves inside the passenger compartment; wherein, when onboard the motor vehicle a telephone conversation is initiated with a remote interlocutor external to the motor vehicle, said electronic control unit is configured to: - select, from said plurality of sound sources, one or more sound sources chosen to emit, inside the passenger compartment, sound waves transmitting what is communicated by the remote interlocutor during the telephone conversation; and - drive the one or more sources selected so that the sound waves emitted by them and transmitting what is communicated by the remote interlocutor during the telephone conversation are directed towards at least one desired listening position within the passenger compartment of the motor vehicle; the system being characterized in that said electronic control unit is configured to generate in real time at least a first set of digital filters, said first set of digital filters being generated in real time based on: - a predefined acoustic model of the passenger compartment of the motor vehicle or a part thereof; and - the emissive characteristics of the one or more sound sources chosen and their position within the passenger compartment; and - a predefined acoustic pattern of a predetermined extension area outside the passenger compartment of the motor vehicle, wherein the electronic control unit is configured to drive the appropriately selected one or more sound sources by applying to them the real-time generated first set of digital filters so that the sound waves emitted by them and transmitting what is communicated by the remote interlocutor during the telephone conversation are selectively directed towards the at least one desired listening position. - an electronic control unit suitable to be mounted on board of the motor vehicle; - a plurality of sound sources suitable to be mounted on board the motor vehicle in predefined positions and suitable for emitting sound waves inside the passenger compartment; - select, from said plurality of sound sources, one or more sound sources chosen to emit, inside the passenger compartment, sound waves transmitting what is communicated by the remote interlocutor during the telephone conversation; and - drive the one or more sources selected so that the sound waves emitted by them and transmitting what is communicated by the remote interlocutor during the telephone conversation are directed towards at least one desired listening position within the passenger compartment of the motor vehicle; - a predefined acoustic model of the passenger compartment of the motor vehicle or a part thereof; and - the emissive characteristics of the one or more sound sources chosen and their position within the passenger compartment; and - a predefined acoustic pattern of a predetermined extension area outside the passenger compartment of the motor vehicle,