Adjustable sidetone and active noise cancellation in headphones and similar devices

A headphone system comprising:

• active noise cancelling means (ANC) having a feedback (FB) signal path, a feed forward (FF) signal path, and a sidetone signal path;
• and
• a control member that can be displaced or rotated between opposite positions,
• wherein the control member is configured to control a gain of the FF signal path and a gain of the sidetone signal path,
• wherein,
• when the control member is at a first extreme position, the gain of the FF signal path is at a maximum level and the gain of the sidetone signal path is at a minimum level,
• wherein, when the control member is at a second, opposite extreme position,
• the gain of the FF signal path is at a minimum level and the gain of the sidetone signal path is at a maximum level,
• wherein, when the control member is rotated or displaced from a middle position in a first direction, the gain of the sidetone signal path increases gradually from said minimum level to said maximum level and the gain of the FF signal path remains at said minimum level, and
• wherein, when the control member is rotated or displaced from the middle position in a second direction opposite the first direction, the gain of the FF signal path increases gradually from said minimum level to said maximum level and the gain of the sidetone signal path remains at said minimum level.