Dual Element Headphone

This invention relates to headphones for sound reproduction with high fidelity, and in particular to dual element headphones having one transducer for each ear directed to reproducing higher frequencies and one transducer for each ear directed to reproducing lower frequencies.

Designers of loudspeakers have long recognized the need for more than a single acoustic transducer to faithfully reproduce the entire audio spectrum. Quality loudspeakers may contain from two to five separate acoustic transducers, each designed to operate over a specific portion of the audio spectrum. Crossover networks are employed to distribute the plied audio signal to the proper acoustic transducer and these typically include circuits comprised of resistors, capacitors and inductors.

In the same vein, headphones having two transducer elements for each side are known in the art. Refer particularly, for instance, to Piribauer, U.S. Pat. No. 3,943,304, wherein there is disclosed a headphone speaker system which combines a dynamic transducer for lower frequencies with an electrostatic transducer for higher frequencies. Similarly, the disclosure of Mathis, U.S. Pat. No. 4,418,248, shows use of two transducers, in this case using a dynamic transducer for lower frequencies and a piezoelectric transducer for higher frequencies. And Andre et al, U.S. Pat. No. 4,965,836 discloses use of two dynamic transducers, a larger one for lower frequencies and a smaller one for higher frequencies. In each of the headphones disclosed in these patents, the transducers are oriented substantially coaxially, so that the sound from the two transducers emanates in almost entirely the same direction.

This invention relates to improvements to the headphone and loudspeaker apparatus set forth above and to solutions to some of the problems raised or not solved thereby.

The invention comprises a dual element headphone for use by a listener. According to this invention, a first acoustic transducer is mounted within a first housing so as to direct sound in a certain direction out of the first housing. The first housing is sized small enough so as to at least partially fit into the cavum concha of a listener's ear, and yet be larger in area than the entrance of the external acoustic meatus of the listener's ear. Means are provided for supporting the first acoustic transducer in the listener's ear so as to direct the sound generated by the transducer toward the entrance of the external acoustic meatus. A second acoustic transducer is mounted within a second housing. That second housing is substantially larger than the first housing, and connected to the supporting means so as to overlie at least a portion of the auricle of the listener's ear. Of course means are provided for dividing the electrical signals received by the headphone, and transmitting signals for higher frequencies to the first, smaller transducer and signals for lower frequencies to the second, larger transducer. The supporting means would normally include a headband and mounting plate, providing a set of these transducers for association with each ear. The first transducer may be flexibly mounted to the supporting means for improved comfort and sound fidelity.

Other objects and advantages of the invention will become apparent hereinafter.

FIG. 1 is a perspective view of a headphone constructed according to a preferred embodiment of the invention.

FIG. 2 is a side elevational view, partially in section, of the transducer assembly of the headphone shown in FIG. 1.

FIG. 3 is a front elevational view, partially in section, of the transducer assembly of the headphone shown in FIG. 1.

FIG. 4 is a top plan view, partially in section, of the smaller transducer, taken along line 4--4 of FIG. 2.

FIG. 5 is a side elevational view, partially cut away, of the transducer assembly of the headphone shown in FIG. 4 along line 5--5.

FIG. 6 is a cross sectional view, taken generally along line 6--6 of FIG. 3 .

Referring now to FIG. 1, there is shown a headphone apparatus 10 constructed according to a preferred embodiment of the invention. The headphone 10 includes a headband 12, generally fitted over the head of a listener. To each end of headband 12 is attached a transducer assembly 14, by means of an earcup assembly 16.

As shown in FIGS. 2, 3 and 6, according to the invention each transducer assembly 14 includes a large transducer 18, mounted by any suitable means to the earcup assembly 16. Generally such mounting means will include a mounting plate 20 to which large transducer 18 is attached. Since a portion of mounting plate 20 is positioned in front of transducer 18, the mounting plate is provided with slots 20a, to permit passage of sound therethrough. Large transducer 18 is of a size substantially larger than the cavum concha 22 of the listener's ear. Mounting plate 20 is connected to the headband so as to position itself and large transducer 18 substantially flat against the listener's auricle 24.

The invention also calls for another, smaller transducer 26 affixed within a housing 28. This housing 28 is associated with large transducer 18 so that sound emanates from the smaller transducer 26 in a direction transverse to the direction of the sound emanating from the large transducer. In the embodiment shown in the drawing FIGURES, the housing 28 is attached to the mounting plate 20 and projects outwardly therefrom. As shown in FIGS. 3 and 6, housing 28 projects substantially perpendicular to the mounting plate 20, and is sized so as to at least partially fit into the cavum concha 22 of the listener's ear. Housing 28 is larger in area, however, than the entrance of the external acoustic meatus 30 of the listener's ear. When in use by the listener, then, housing 28 projects into the cavum concha 22 and aligns the smaller transducer 26 generally with the entrance to the external acoustic meatus 30. With smaller transducer 26 thus positioned, the sound emanating therefrom is transmitted almost directly to the tympanum 32 of the listener's ear.

The invention also provides for conventional crossover filter means 34 (FIG. 4) for dividing the electrical signal into a lower frequency component and higher frequency component. By this means 34 the lower frequency component is transmitted to the larger transducer 18 while the higher frequency component is transmitted to the smaller transducer 26. Since the smaller transducer 26 is positioned almost directly facing the tympanum 32, the higher frequencies are transmitted to the tympanum with great fidelity. Correspondingly, since the larger transducer 18 is positioned further away from the tympanum 32, the relatively larger amplitudes of the lower frequencies are prevented from uncomfortably over-exercising the tympanum.

For greater comfort in using and wearing the headphone 10, it is known to provide padding material, such as foam pads 36, to cover the large transducer 18 and mounting plate 20. In the present invention, in order to further improve comfort in use, the mounting of the housing 28 to the mounting plate 20 may be a flexible mounting 38. This flexible mounting 38 includes a boot 40 attached to the plate 20, the other end of the boot easily carrying the relatively lightweight housing 28. The signals to the smaller transducer 26 should then be carried by some flexible means such as flexible wires 42 (FIG. 5) rather than some other means such as solid traces.

While the apparatus hereinbefore described is effectively adapted to fulfill the aforesaid objects, it is to be understood that the invention is not intended to be limited to the specific preferred embodiment of dual element headphone set forth above. Rather, it is to be taken as including all reasonable equivalents within the scope of the following claims.