A body dryer includes an airflow generator to generate a flow of air, an inlet to pass air from the surroundings to the airflow generator, an outlet to vent the air from the airflow generator, a body, and a movable bar, the bar supported by the body. A drive assembly is provided between the body and the bar, the bar movably driven relative to the body. A noise cancellation device is provided to cancel or reduce noise in at least one of the airflow generator and the drive assembly.

A method and system for noise cancellation is disclosed. In one embodiment, the method may include receiving, from a first sensor, a first signal indicative of a noise generated by an equipment. The first sensor may be configured to generate the first signal indicative of the noise generated by the equipment. The first sensor may be positioned in proximity to the equipment. The method may further include generating a noise cancellation signal based on the first signal and triggering a speaker to generate a sound corresponding to the noise cancellation signal, wherein the speaker is positioned in proximity to the equipment.

The present invention is in the field of an active sound-cancellation system, an open fluid-duct comprising such an active sound-cancellation system, such as an air duct, and an active sound-cancellation computer program comprising instructions for operating such an active sound-cancellation system. The active sound-cancellation system reduces noise significantly.

An apparatus for natural ventilation of a room, with a room delimited by walls, at least one door or one window installed in one of the room walls, a ventilation passage which is fitted to the door or the window and which communicates between the outside of the room and the inside of said room in such a way as to allow natural ventilation between the outside and inside of said room, the passage having a first end opening into the room and a second end opening to the outside of said room, and a noise absorber capable of attenuating sound waves propagating in the ventilation passage, the attenuation being realized by the generation of a counter-noise which is superimposed on said sound waves or by absorbing all or part of said sound waves.

A sound-modulating device used in a confined space is provided. The sound-modulating device includes an event detector and an audio module in communication with each other. The event detector detects an event and generates a trigger signal in response to the detected event. The audio module plays a music segment in response to the trigger signal. The frequencies of the music segment range from 20 Hz to 20000 Hz. The intensities of the music segment are smaller than or equal to 75 dB.

An indoor sound-modulating device is provided. The indoor sound-modulating device includes a low-frequency noise detector, an automatic actuator and an audio signal generator. The low-frequency noise detector detects low-frequency noise and generates a first modulating signal in response to the detected low-frequency noise. The automatic actuator issues a second modulating signal in response to a predetermined state. The audio signal generator generates a low-frequency audio signal for eliminating the low-frequency noise in response to the first modulating signal and generates a high-frequency repellent audio signal in response to the second modulating signal. The low-frequency audio signal has a frequency ranging from 20 Hz to 350 Hz, while the high-frequency repellent audio signal has a frequency not less than 8000 Hz.

An air conditioning apparatus includes a housing, a fan arranged in an inside of the housing, a suction-side flow path between a suction opening of the housing and a suction port of the fan, and a silencer with a tubular shape. The silencer has a propagation path through which a sound propagates. The silencer includes an opening that is open at one end of the propagation path and communicates with the suction-side flow path, and a blocking part that blocks an other end of the propagation path and reflects, toward the opening, the sound that has passed through the propagation path.

The present invention is in the field of an active sound-cancellation system, an open fluid-duct comprising such an active sound-cancellation system, such as an air duct, and an active sound-cancellation computer program comprising instructions for operating such an active sound-cancellation system. The active sound-cancellation system reduces noise significantly.