JPH0646839B2 - Speaker device - Google Patents

Description

The present invention relates generally to speaker systems, and more particularly to audio signals separated from reduced and high range sounds for high fidelity reproduction from transducers specially made for high fidelity. Related equipment. The high frequency acoustic transducer has a size, structure,
It is well known that even operating principles can be quite different from those of low frequency converters. Separately actuated transducers have long been available which are capable of faithfully reproducing sound within a given frequency band. Efforts to reproduce high fidelity sound in the human ear use how many frequency divisions and converters should be used to operate the transducer within its assigned frequency range when frequency division is required. Should,
The goal is to determine how the transducers should be structured and combined with each other, and perhaps need many other considerations, both wide and narrow.

It has been conventional to provide speaker systems in which the audible signal is split into upper and lower frequencies and distributed to a transducer specifically designed to best reproduce high and low frequency tones. Also, for various reasons, it was common to make a combination of two or more transducers in which the high frequency transducer was mounted coaxially with respect to the low frequency transducer in a single assembly.

Coaxial loudspeakers have used independent transducers in the past, but their interrelationship is almost entirely a matter of mechanical placement with some consideration for the acoustic effects that result from it. Generally, "coaxial" speaker systems use one or more high frequency drivers mounted on a low frequency device by post or bridge supports, often resulting in phase cancellation between the drivers and diffraction due to the support system. Has an irregular frequency response characteristic due to the effect.

It is also well known that there are at least two types of drive mechanisms in acoustic transducers, namely permanent magnets, moving coil types and piezoelectric types.

The speaker system of the present invention includes a low frequency dynamic radiator type transducer or woofer and one or more high frequency transducers or tweeters mounted in one assembly, but requires the elaborate and expensive mounting of the prior art. Not. The woofer unit is generally a permanent magnet, moving coil structure, and its dynamic radiator is a diaphragm. The tweeter comprises a small diameter diaphragm mounted in a space formed by the diaphragm and having a driver structure including a piezoelectric element or other driving element at its apex.

In this structure, the entire mechanism forming the tweeter moves in harmony with the low frequency diaphragm within the range of the piston and constitutes a part of the total momentum of the low frequency driver. This arrangement eliminates the commonly used mounting posts or brackets that support the high frequency unit and improves the overall frequency response, dispersion, time, and phase characteristics of the speaker system.

Accordingly, one object of the present invention is to provide an improved multi-driver speaker structure with improved overall frequency response, dispersion, time and phase characteristics.

Another object of the present invention is to provide an improved multi-driver loudspeaker structure which does not require a separate mounting device for the central or upper frequency drive unit.

These and other objects of the invention will be readily apparent to those of ordinary skill in the art upon reading the following detailed description of the accompanying drawings.

In the embodiment of the invention shown in FIG. 1, the low frequency converter or woofer is of the permanent magnet, moving coil type and includes a permanent magnet assembly to which a frame 12, which is generally somewhat conical in shape, is fixed. The frame 12 constitutes an opening 13 which together forms the front shape and area of the transducer.
The shape of the opening 13 formed by the frame may be, for example, an oval other than the circular shape. The diaphragm 14 of the woofer extends or protrudes outward in a conical shape as a whole, and its outer edge is fixed to the periphery of the frame 12 by a flexible hanger 16. Inside the diaphragm 14 is a voice coil 2 which surrounds the central pole 22 of the permanent magnet assembly 10.
It is fixed to a voice coil foam 18 with 0 in the lower part, which is a magnetic coil of conventional shape.
Placed in 4. Up to this point in the description, the structure of the transducer is quite conventional.

A high frequency converter or tweeter is a tweeter cone 30
, Whose central axis is generally aligned with the central axis of the woofer cone 14. Tweeter cone 30 has a slightly larger extent than woofer cone 14 and is considerably smaller in size. On the outer periphery of the cone 30, a foam compliance ring 34 may be placed between the cone 30 and the surface of the diaphragm 14. Damper or reinforcement 32 extending behind cone 30 along a portion of its surface
And 36 are provided to smooth the response and to insulate the leads if necessary. The driver element 38 is placed at the top of the cone 30. The driver element 38 includes a piezoelectric crystal, which is well known as a bimorph or multimorph. An electrical lead 40 is coupled to the crystal 38 and is conventionally mounted through the woofer cone 14 and attached to a portion of the frame 12 at an input terminal 44.
Go to. The lead 40 from the crystal 38 is the terminal 44
Is connected to the lead 43 connecting to the voice coil 20. Crystal 38 and voice coil 20 are thus electrically connected in parallel.

Both drivers 3 without using crossover network
A pair of input leads may be connected to 8 and 20 because the crystal driver 38 acts as a high pass filter and tweeter driver, and also with the thickness of the crystal, the coupling coefficient and diameter, and the diameter of the cone 30. This is because the effective crossover frequency is supplied anywhere within the range of 1 to 10 KHz due to its shape or the like. External filter networks can be used if desired.

Damping rings 32 and 36 made of fiberglass insulating material suppress unwanted vibration modes as shown, while foam compliance ring 34 provides mechanical coupling between the woofer and woofer cones 14, 30 in the response crossover region. Give a means to control. Thus, the desired acoustic response can be achieved by appropriate selection of tweeter mechanism materials, dimensions, symmetries, and positions, as well as variations in decoupling ring 34 and damping rings 32 and 36. Tweeter Cone 30
Can be hung in front of the woofer cone in several ways. The perimeter of tweeter cone 30 can be attached directly to the woofer cone or via a flexible member. The tweeter cone 30 supports the tweeter cone 30 from its crystal driver 38 and attaches the crystal driver 38 to the woofer's voice coil form 18 or directly to the apex of the woofer cone to provide structural support between the cones. It can be hung in front of the woofer cone without making contact. Tweeter cone 30 may also be attached to any suitable portion of the body of woofer cone 14 for wide angle dispersion.

When actuated in response to a low frequency electrical signal, the transducer assembly looks like just one piston. Actuation in response to signals at frequencies above the crossover frequency is essentially independent of the fact that the high frequency cone 30 is actually mounted on a support that exhibits little or no movement at these high frequencies. Join the movement as you would. The decoupling device placed between the woofer cone 14 and tweeter cone 30 provides a way to control the degree of movement and phase between the two cones in the mid-zone and upper-zone response regions, thus providing correlation. As explained by the principle, it provides a means for controlling electromechanical feedback to the tweeter drive element. This gives a smooth frequency response characteristic in the response region of the middle band and the upper band. This attachment between the diaphragms 14, 30 leads to improved frequency response and dispersion of the overall system and also to improved time phase coherence over the desired frequency range. From a mechanical standpoint, the device of the present invention eliminates the need for auxiliary mounting brackets often used in other coaxial devices to support high frequency drivers.

In another embodiment of the present invention shown in FIGS. 2 and 3, the permanent magnet assembly 110 comprises a 6 in.times.9 in (15.24 cm.times.).
22.86 cm) and is fixed to a frame 112 having a generally oval or oval front opening. The woofer diaphragm 114 projects outward in a conical shape as a whole. The outer rim of the diaphragm 114 is fixed to the oval front opening of the frame 112 by a flexible hanger 116.
The interior of diaphragm 114 is fixed to a voice coil foam 118 which is attached to a woofer voice coil 120 which is placed in a magnetic air gap 124 in a bullet-like manner.

The tweeter of this embodiment has a tweeter cone 130 whose central axis is about 45 ° away from the axis of the woofer cone 114 as best shown in FIG. Junction area 1
31 is provided on the outer circumference of the cone 130. This junction area 1
The 31 is glued or otherwise attached to the outer peripheral edge 135 of the opening 133 provided in the woofer cone 114, with or without a compliant member.
A piezoelectric bimorph crystal driver element 138 is placed at the apex of cone 130. Electrical lead 140 is connected to crystal 138 and extends to terminal 145 provided on the outer surface of woofer cone 114. The lead 140 from the crystal 138 is connected by a lead 142 to an input terminal 144 provided on the support frame 112. Lead 142 also connects terminal 144 to woofer voice coil 120. Woofer voice
Coil 120 and tweeter driver 138 are thus connected in parallel.

Again, a pair of input leads 142 should be connected to both drivers 1 without the use of a divider or crossover network.
It can be connected to 38 and 120 because the crystal driver 138 acts as a high pass filter.

In another embodiment of the invention shown in FIG. 4, a permanent magnet assembly (not shown) is fixed to a frame 212 having a generally circular front opening. Tweeter
Shape the cone 230 into the woofer cone body 214,
The peripheral portion of the woofer cone 214 can be an extension of the tweeter cone body. The woofer diaphragm 214 spreads outward in a conical shape as a whole. Its outer circumference is secured to the circular front opening provided in the frame 212 by a flexible hanger 216. The interior of diaphragm 214 is secured to a voice coil foam, all voice coils included therein surrounding the central pole of the permanent magnet assembly and placed in a void in the manner previously described. The four high frequency transducers or tweeters 229 are attached to the woofer diaphragm 214 in a manner similar to the attachment of the tweeter diaphragm shown in FIG. Each tweeter 229 includes a tweeter cone 230, the central axis of which is 45 ° away from the central axis of the woofer cone 214, as in the embodiment of FIGS. 2 and 3. Also, the central axes of the tweeter cones are placed at 90 ° intervals about the axis of the woofer cone 214. As previously mentioned, tweeter cone 230 has a slightly larger extent than woofer cone 214 and is much smaller in size.
A piezoelectric driver element (not shown) is placed at the apex of each cone 230. The electrical termination (not shown) of the crystal driving the tweeter cone 230 is made as in the previous embodiment. Again, the crystal driver acts as a high pass filter, and the frequency response of the driver varies with the driver and tweeter cone 230.
It can be partially selected by appropriate selection of physical parameters of.

The advantage of placing the tweeter shaft away from the woofer shaft in the embodiment of FIGS. 1 to 4 is best seen in FIGS.

FIG. 5 shows the prior art 6 in × 9 in (15.24 cm × 22.86 cm) oval speaker frequency response with a coaxial secondary cone called the “wier”. The three frequency response curves correspond to the speaker coaxial (0 °) frequency response, the speaker 30 ° off-axis frequency response, and the speaker 45 ° off-axis frequency response. Even with the wier cone, the off-axis (30 ° and 45 ° off-axis) response of the speaker is much lower than the coaxial response (1 to 3 dB) even at a low frequency such as 2 KHz. At about 4 KHz, the off axis performance is significantly degraded (30 ° off axis is reduced by 5 dB and 45 ° off axis is reduced by 14 dB). 15KHz
, The 30 ° off axis shows a decrease of 13 dB, and the 45 ° off axis shows about the same amount of decrease.

FIG. 6 shows a 6 ″ × 9 ″ (1
5.24cm x 22.86cm) The frequency response of an oval speaker is shown. Off-axis response at 2 KHz is about 1 and 3d
It is maintained at a decrease of B (at 30 ° off axis and 45 ° off axis respectively), but at 5 KHz, the 30 ° off axis response is reduced by only about 1 to 1.5 dB, which is 3.5 to 4 dB from Fig. 5. It is improved, and the off-axis response at 45 ° is reduced by 8 to 8.5 dB, which is an improvement of 5.5 to 6 dB from FIG. At 15 KHz, the improvement is equally significant and the 30 ° off axis response is about
It is only 10.5dB, which is an improvement of 2.5dB from Fig. 5, and the off-axis response at 45 ° is only 8.5dB, which is an improvement of 5.5dB from Fig. 5.

The frequency response characteristics of the embodiment of FIGS. 2 and 3 of the present invention are shown in FIG. In the example tested for FIG. 7, the apex of the tweeter cone protruding into the surface of the surrounding woofer cone is on its way from the woofer cone axis to the compliance ring. In other words, the tweeter is a woofer cone axis. It is installed away from the woofer cone on the way to the compliance ring. At 2 KHz, the 30 ° off-axis response shows a decrease of about 1.5 to 2 dB, and the 45 ° off-axis response shows a decrease of about 5 dB. At 4 KHz, the 30 ° off-axis performance is actually 1 to 1.5 dB higher than the coaxial performance, and the 45 ° off-axis performance is only about 1.5 to 2 dB lower than the coaxial performance, both of which greatly improve the embodiment of FIG. At 15 KHz, both the 30 ° off axis performance and the 45 ° off axis performance are actually higher than the coaxial performance, and at 30 °, it is about 4-5 dB higher than the coaxial performance.
At ゜, it is about 10 dB higher than the coaxial performance. The present invention integrates the low and high range cones directly or via a flexible intermediate attachment means without providing a column for supporting the second transducer, so that the connection between these cones can be achieved. The support member can prevent the phenomenon in which the frequency response of the speaker is distorted, and the mounting structure can be simplified.

In addition, an opening is provided on the surface of the first diaphragm, and the second diaphragm is attached to the outer peripheral edge of the opening directly or through a flexible member, and the second diaphragm moves so that the second transducer moves together with the first diaphragm. Being supported by the first diaphragm, the tweeter cone can be driven in harmony with the woofer cone, and further phase cancellation between the drivers driving the cone and the irregular frequency response due to the diffraction phenomenon due to the support device. Can be removed.

[Brief description of drawings]

1 is a cross-sectional view of a multi-driver speaker device made according to the present invention, FIG. 2 is a front view of a multi-driver speaker device made according to the present invention, and FIG. 3 is a view of the device shown in FIG. FIG. 4 is a cross-sectional view of the device of FIG. 2 taken generally along line 3-3, and FIG.
A front view of a driver speaker system, FIGS. 5 through 7 show prior art speakers and 2 made in accordance with the present invention.
It is a figure which shows the frequency response characteristic of one speaker. 10 ... Permanent magnet assembly; 12 ... Frame; 14 ... Woofer cone; 20 ... Voice coil; 24 ... Magnetic air gap; 30 ... Tweeter cone

Claims (2)

[Claims] 1. A first converter having a driver (20) and a first diaphragm (14) for reproducing sound in a low frequency range of an audio frequency range, and for reproducing a sound in a high frequency range of an audio frequency range. A second transducer having a piezoelectric driver element (38) and a second diaphragm (30); and a first diaphragm (14) for supporting the second transducer.
Intermediate attachment means (32, 34, 36) attached to the second diaphragm, and the second diaphragm includes the first attachment means through the intermediate attachment means.
Attached to a diaphragm, connecting the second diaphragm to the first diaphragm from the inside of the peripheral portion of the first diaphragm, the second transducer being supported by the first diaphragm,
And a multi-driver round loudspeaker characterized by being able to move freely with the first diaphragm in an unrestrained manner. 2. A first converter having a driver (120) and a first diaphragm (114) for reproducing sound in a low frequency range of an audio frequency range, and for reproducing a sound in a high frequency range of an audio frequency range. A second transducer having a piezoelectric driver element (138) and a second diaphragm (130) is provided, an opening (133) is further provided on the surface of the first diaphragm (114), and an outer peripheral edge (135) of the opening has a first opening. Two diaphragms (130) are attached directly or via a flexible member, the second diaphragm being supported by the first diaphragm (114) so that the second transducer moves together with the first diaphragm (114). A multi-driver round speaker that is characterized by being.