Abstract: A compact noise suppression circuit for a small speaker system and having a circuit board with a left signal input connection and a right signal input connection and a ground connection, and further having a left speaker supply connection and a left speaker return connection, and a right speaker supply connection and a right speaker return connection, and further having a left bifilar coil and a right bifilar coil, and left and right coil connections on the circuit board, and means securing said left and right bifilar coils to respective coil connections on the circuit board. Also disclosed is a compact portable audio player system incorporating such a noise suppression circuit, and a noise suppression circuit for a mon-aural signal system.

Abstract: An earbud sound system for a small speaker system having at least one earbud with a speaker and having, an earbud housing body defining a hollow interior a a circuit board within the housing body and having a signal input connection and a ground connection, and a speaker output connection and a speaker return connection; a bifilar coil unit having first and second coils wound in a bifilar manner, mounted on the circuit board within the housing body, and there being two first coil connections, and two second coil connections on the circuit board, for supporting the bifilar coil unit in a secure manner on the circuit board.

Abstract: An earbud sound system for a small speaker system having at least one earbud with a speaker and having, an earbud housing body defining a hollow interior a a circuit board within the housing body and having a signal input connection and a ground connection, and a speaker output connection and a speaker return connection; a bifilar coil unit having first and second coils wound in a bifilar manner, mounted on the circuit board within the housing body, and there being two first coil connections, and two second coil connections on the circuit board, for supporting the bifilar coil unit in a secure manner on the circuit board.

Abstract: A method of operating a single speaker driver circuit having, a low frequency input coil connected between an audio circuit output and the input of the speaker, a low frequency return coil, connected between the return of the speaker and the return of the audio signal, the low frequency return coil being bifilar wound with the low frequency input coil, and a higher frequency input coil connected between the audio circuit output and the return of the audio circuit, and a secondary coil connected between the input of the speaker, and ground, the higher frequency input coil and the secondary coil being bifilar wound with one another and acting as the primary and the secondary of a transformer so the higher frequency signals passing through the higher frequency input coil induce secondary signals in the secondary coil, and a method of operating an audio frequency reproduction system using such a driver circuit.