Selectable impedance, constant efficiency electromagnetic transducer
OwnerEnrique Stiles, Richard Calderwoodinventors
Life of this patent
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Abstract
An electromagnetic transducer such as an audio speaker, having three or more voice coils disposed in one or more magnetic air gaps. The voice coils can be combined in any permutation of series/parallel connections, to select any one of a predetermined set of impedance values for the transducer. Optionally, the transducer is equipped with a set of different terminal connector plugs, each of which automatically performs the series/parallel connections for its designated impedance value. All voice coils may be selected as active, allowing for a constant maximum efficiency, regardless of which impedance option is selected.
Claims24
An electromagnetic transducer comprising:
- (a) a motor structure having at least one magnetic air gap;
- and
- (b) a diaphragm assembly coupled to the motor structure and including,
- (1) a diaphragm,
- (2) a bobbin coupled to the diaphragm,
- (3) at least three voice coils each disposed in at least one of the magnetic air gaps,
- wherein at least two of the voice coils are of different impedances, and
- (4) for each of the voice coils,
- (i) a + terminal connector, and
- (ii) a − terminal connector;
- whereby the voice coils can be connected in at least four series/parallel combinations to give the electromagnetic transducer at least three different impedance values.
An electromagnetic transducer for receiving an alternating current signal via + and − wires from an amplifier, the transducer comprising:
- a frame;
- a motor structure coupled to the frame and having at least one magnetic air gap;
- a diaphragm assembly coupled to the frame and including a first voice coil VC1, a second voice coil VC2, and a third voice coil VC3, each voice coil disposed in at least one of the magnetic air gaps, wherein at least two of the voice coils have impedances which differ by at least 10%;
- and
- a terminal block coupled to one of the frame and the motor structure and including,
- a VC 1+ terminal connector and a VC 1− terminal connector electrically connected to respective ends of the first voice coil,
- a VC2+ terminal connector and a VC2− terminal connector electrically connected to respective ends of the second voice coil,
- a VC3+ terminal connector and a VC3− terminal connector electrically connected to respective ends of the third voice coil,
- whereby the voice coils can be connected in any of the following series/parallel configurations by appropriate connections of the terminal connectors to each other and to the + and − wires,
- 1) VC1∥VC2∥ VC3
- 2) (VC1∥VC2)—VC3
- 3)(VC1∥VC3)—VC2
- 4) (VC2∥VC3)—VC1
- 5) VC1—VC2—VC3.
Dependencies are inferred from the claim text.