JP2014099681A - Speaker and driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which, while a passive radiator is effective for a small sized speaker excellent in bass reproduction capability, as the size decreases, trade-off relations between factors that determine properties such as a precise and complex structure and performance that is not so improved for cost become significant and design becomes significantly difficult.SOLUTION: Bass reproduction capability is significantly improved by making a driver free through a flexible edge without being fixed to vibrate the driver itself and matching factors so that both vibrations of a voice coil of the driver and the entire driver becomes close to be in-phase in a low sound range that is desired to be reproduced.

Description

Improved bass reproduction performance of small speakers.
Cost reduction of small speakers with excellent bass reproduction capability.
Improved difficulty and design accuracy of small speaker design with excellent bass reproduction performance.

The following terms are defined throughout the entire text including the claims.
The meanings of terms defined in the claims are the same in the description of the specification.
Contents in {} have priority over contents outside {}.
{Small and high performance} means that the size of the speaker is small and the bass reproduction performance is excellent.
{Design} means {work for creating production drawings or production procedure manuals} where the performance in the completed state can be produced as expected.
{Difficult to design} means that it is difficult to predict the performance in the finished state at the stage of production drawing.

Passive radiators are used to obtain powerful bass reproduction performance with small speakers, but the contradictory factors of cost, size, and bass reproduction performance are barriers to miniaturization beyond the limits. On the other hand, the function of the passive radiator is required to have as wide an acoustic radiation area as possible. However, as the size becomes smaller, it becomes more difficult to ensure the acoustic radiation area.

Improved size vs. limit performance for small high performance speakers.

The {driver} is not fixed directly to the enclosure or structure, but is attached via the {second edge} that the {driver} itself can vibrate.

Claim 1 relates to the basics of the present invention.
The basis of the present invention is that both functions of {weight and radiation surface} of the passive radiator are combined with {driver} itself. {The {driver} itself vibrates by the action of {the load on the cone caused by the vibration of the cone}}, so that {{the radiation area enclosed by the outer periphery of the driver} itself} is to be used for low-frequency radiation. .
When the cone tries to move outward, the force in the opposite direction naturally acts on the magnetic circuit via the voice coil. As a result, the frame that supports the magnetic circuit also has {the force acting on the voice coil The force in the opposite direction} acts. The {driver} frame is supported by the {second edge} without fixing the {driver} frame, so that the {driver} frame tries to move in the opposite direction to the force acting on the voice coil. In the conventional {driver}, the frame is attached to the {enclosure}, but the {driver} of the present invention is attached to the {enclosure} via the {second edge} so that the driver can vibrate in the direction in which the voice coil vibrates. With structure.
A function composed of {driver} and {second edge} is defined as {floating driver}.

When {floating driver} is attached to the enclosure, an internal space consisting of the enclosure and {floating driver} is created. This internal space is defined as {air chamber}.
Whether {air chamber} is sealed is not the essence of the present invention, but in the following description, {air chamber} is assumed to be sealed. When {{driver} voice coil} moves outward, the cone moves outward, and {driver fixed system} tries to move inward. The pressure in the air chamber varies depending on both movements. Due to this pressure change, a slightly complicated force acts on the {floating driver}. Here, {{floating driver} and voice coil} constitute {a vibration system having two degrees of freedom}.

This vibration system has a vibration mode that depends on the following main specifications.
{Mass of {vibration system} of {floating driver}}, {mass of {fixed system} of {floating driver}}, {effective acoustic radiation area by cone and edge}, {volume of air chamber}, {{ Floating driver} overall mass}, {{floating driver} overall effective acoustic radiation area}, {edge and damper stiffness}, {{second edge} stiffness}.
By matching these specifications, it can be designed to have a {required bass reproduction band} and a {common in-frequency bass representative frequency}. In the vicinity of {representative frequency of in-phase bass range}, {{floating driver} and {driver vibration system} phase of vibration} are close to in-phase. Then, the design is made so that the vicinity of {the in-phase bass region representative frequency} overlaps with the {necessary bass reproduction band}.

Among the various vibration modes of this vibration system, the driving energy generated from the voice coil near {the in-phase bass range representative frequency} passes through {{change in pressure in the air chamber}} and {displacement in the second edge}. Floating driver}.
In this vibration system, there exists {combination of specifications} that makes {the frequency at which the electrical impedance of the {driver} is minimal}, that is, {the in-phase low frequency range representative frequency} exist. As a result, when driven by an amplifier having a low impedance output characteristic, the power consumption of {driver} increases in the vicinity of {in-phase low frequency range representative frequency}. This increase in power consumption leads to an increase in acoustic radiation energy. And in the vicinity of this {in-phase low-frequency representative frequency}, the phase of {{cone vibration} and {floating driver vibration}} is {in phase or close to in phase}, so there is no cancellation of acoustic radiation due to both vibrations. A low distortion bass is played. The same applies to the passive radiator type speaker designed in the best condition.

As described above, in the {required bass reproduction band}, vibration generated by the voice coil is transmitted as vibration of the entire {floating driver}. As a result, a wider bass radiation area increases radiation efficiency. For the mid-high sound, the vibration of the {floating driver} is so small as to be negligible due to the mass of the {driver fixed system}, and is the same as that of a normal speaker. In addition, since the mid-high sound is added to the low-frequency vibration, Doppler modulation distortion occurs, but this is the same as the full-range speaker capable of reproducing the low sound.

Claim 2 relates to a method for facilitating the use of {driver} as {floating driver}.
By mounting {second edge} on {driver} in advance, {floating driver} can be supplied as a standard part.

Claim 3 relates to a technique for suppressing mechanical vibration of the entire {{speaker} or {device}} during bass reproduction.
Balanced by a factor of {acceleration and mass} between {{floating driver} and {1 passive radiator} in vibrations near {{in-phase bass range representative frequency} or {reverse phase bass range representative frequency}}. To cancel both mechanical vibrations and greatly reduce the vibration of the entire {{speaker} or {appliance device}}.

Claim 4 relates to an application apparatus of the present invention.
Since it is a small and excellent {speaker} or {appliance device} with low-pitched sound performance, desktop speakers are mainly applicable to small ones from portable terminals and large ones from television sets and passenger cars.
The vibration of the {floating driver} can be radiated acoustically from the {floating driver}, and the vibration can be transmitted to the structure of the application device and radiated. Especially by mounting {{floating driver} or {{floating driver} consisting of {speaker}}} on the windshield and pillar of a passenger car, you can not only reproduce powerful bass using a small speaker, but also {driver ’s seat Speaker system that allows sound to be heard from the front of the speaker}.
A portable terminal equipped with a sound reproduction function is small, so that efficient low-frequency reproduction is difficult. However, it is possible to significantly improve low-frequency reproduction using a {floating driver}.
It can be applied to a television set that requires a low-profile speaker that is thin, has excellent bass reproduction performance, has low mechanical vibration, and low cost.

Claim 5 is that {speaker} using {floating driver} optimizes the specifications of {{driver}, {second edge}, {enclosure}} for efficient reproduction of bass with {heavy bass playback band} It relates to two requirements for designing.
The first of the two requirements is
This is a condition for efficiently transmitting the vibration energy of the voice coil to the floating driver when {the vibration of the voice coil and the vibration of the floating driver are in phase} in the {required bass reproduction band}. {The vibration of a voice coil with a small radiation area is reduced} and {the vibration of a wide floating area {the floating driver} is increased}, the bass radiation efficiency is significantly improved.
The second of the two conditions is
In the vicinity of {reverse phase low frequency range representative frequency}, {vibration of both the voice coil and {floating driver}} vibrates greatly in the vicinity of the reverse phase and generates distortion. However, {an out-of-phase low-frequency range representative frequency} and {in-phase range required low-frequency representative frequency} are related to each other, and {experienced low-pitched sound reproduction is possible when both frequencies are close to each other} Can be confirmed. The same applies to a passive radiator type speaker system designed in the best condition.
The above two conditions, that is, {{appropriate design of in-phase bass region representative frequency} and {reverse phase bass region representative frequency}} are {performance required for {applied apparatus}} and {{necessary bass reproduction band}. It is an indispensable factor for matching the condition for efficient bass reproduction}.

The sixth aspect of the present invention is a necessary condition for reproducing the low-sound quality better by using the {speaker} of the present invention with an application device.
The {speaker} of the present invention only has a bass reproduction capability, and a driving method such as a normal large-diameter speaker not only does not reproduce a convincing bass in the {necessary bass reproduction range}, but also {reversely Abnormal vibration exceeding the dynamic range of {driver} occurs in the vicinity of the phase bass representative frequency}. {Filter with gain emphasis characteristics in this frequency range} is effective for extracting powerful bass reproduction sound in {necessary bass reband}. In the {reverse phase bass reproduction band}, a {filter having a damping characteristic for suppressing abnormal vibration} is required.
By providing these filters on the amplifier side, practically good bass reproduction can be obtained.

Claim 7 is a method for specifying the specifications of {speaker} necessary for standardizing {acoustic design level work for obtaining good bass reproduction} when {speaker} of the present invention is incorporated in {appliance device}. About. At least {presenting necessary environmental conditions such as enclosure volume} in {required required bass reproduction band} simplifies design work and improves design accuracy. Since the size of the speaker can be reduced, there is a possibility of promoting the standardization of {driver}. By standardizing {driver}, which is the main part of {speaker}, so that resistors and capacitors are standard parts, it is possible to significantly improve the current inefficient acoustic design work.

First,
An ordinary driver's metal frame or plastic frame has an attachment structure to the enclosure, but instead of this attachment structure, a resilient rubber {second edge} is provided, and the outer periphery of {second edge} is {enclosure } In close contact with the speaker. Or a speaker with a metal or plastic frame adhered to the outer periphery of the {second edge} and the frame in close contact with the enclosure.

Secondly, a passive radiator is provided on the back side of the driver of the enclosure of the first speaker so as to face the driver, and mechanical vibration caused by {driver vibration and passive radiator vibration} is canceled in the {required bass reproduction band}. speaker.

Thirdly, regarding the {{driver}} provided with {{second edge}} or {driver}} provided with a frame around the {{second edge} of the first embodiment, the assumed enclosure volume , {{Estimated value for in-phase bass region representative frequency} and {estimated value for opposite-phase bass region representative frequency}} are associated as part of the specifications of {driver} {driver}.

Fourth, a {first or second speaker} or {third driver} is {attached to a cabinet or chassis} {an acoustic device, a television set, a mobile phone, a smartphone}.

Fifth, a passenger car equipped with {first or second speaker} or {third driver} on {windshield or pillar or dashboard}.

Sixth, a house in which {first or second speaker} or {third driver} is mounted on {wall or door}.

Seventh, a table or desk equipped with {first or second speaker} or {third driver}.

Eighth, a speaker in which {first speaker} or {third driver} is mounted on a {glass or wood} board.

Ninth, {{acoustic signal processor of mobile terminal called mobile phone, smart phone, personal computer, television set, car stereo}} has an {{required bass reproduction range} enhancement filter and {reverse phase bass reproduction band} }, An application device having {{first or second speaker} or {third driver}}, incorporating the attenuation filter at}.

Claims (7)

{Driver} is a {function for converting electrical signals into acoustic signals} consisting of {permanent magnets, magnetic circuits, voice coils, bobbins, cones, dampers, edges, and frames}
{Enclosure} is a {box for providing a sealed space on the back of {driver}} or {structure for mounting {driver}}
{Speaker} is made up of {driver} and {enclosure}
{{Driver} has the flexibility to vibrate in the {vibration direction of the voice coil that is the part of {driver}}} {where the edge connecting {{driver}} and {enclosure}} is {second edge} age,
{Speaker} characterized in that {driver} and {enclosure} are coupled through the second edge. The {driver} having the second feature of mounting the {second edge} defined in claim 1. {Speaker} has a third feature that a {passive radiator comprising a weight and a diaphragm} is attached to {the back of the mounting surface of {driver}} of {enclosure} defined in claim 1. {Applied device} having {sound reproduction function} or {passenger car} as {applied device} {{speaker} defined in claim 1 or claim 3} or {driver {} in claim 2} }. The {driver} part {{voice coil} or {cone structurally integrated with the voice coil}} is defined as {driver vibration system},
{{Frame supporting the driver vibration system}} or {Magnetic circuit structurally integrated with the frame} is {Driver fixing system},
The vibration of {driver vibration system} with respect to {driver fixed system} is {full range vibration},
The structure that fixes {second edge} is {device fixing system},
The vibration of {driver fixed system} relative to {device fixed system} is {bass vibration},
{For application devices, {required bass reproduction band}} is set as {necessary bass reproduction band}
{
At a specific frequency within the {required bass reproduction band},
{{Low range vibration} and {full range vibration} are in phase or close to phase} or {{full range vibration} has a minimum amplitude} or {{speaker} has an electrical impedance of Is in a state of being minimal}
}
The frequency corresponding to one of them is defined as {in-phase bass range representative frequency},
The fourth feature is that there is {in-phase bass frequency representative frequency},
{
In the frequency range lower than the lower limit or lower limit of {required bass reproduction band},
{The phase of {low range vibration} and {full range vibration} is 90 degrees or close to 90 degrees} or {the state of {full range vibration} is at a maximum}} or {electricity of {speaker} The impedance is at a maximum} or
}
The frequency corresponding to one of these is {reverse phase bass range representative frequency},
The fifth feature is that there is a {reverse phase bass range representative frequency},
{Speaker} or {application device} having fourth and fifth features. The signal processing filter for increasing the signal of the {required bass reproduction band} including the {in-phase bass band representative frequency} defined in claim 5 is defined as {in-phase band enhancement filter}.
The sixth feature is that it has a {common-mode enhancement filter},
The vicinity of {reverse phase bass range representative frequency} defined in claim 5 or {the whole low frequency band including the vicinity} is set as {reverse phase bass reproduction band},
The signal processing filter for attenuating the signal of the {reverse phase bass reproduction band} is {reverse phase range attenuation filter},
The seventh characteristic is that it has a {anti-phase region attenuation filter},
{Applied device} having sixth and seventh features. {Specification of {driver}} defined in claim 2 with a specific specification as {driver specification}
Let {Driver} wearing environment sample be {Assumed environment}
The specifications of {assumed environment} are {assumed environment specifications}
The sound reproduction performance when a {specific {driver} 's {driver specifications}} and {specific {assumed environment specifications}} are combined is defined as a specific {driver} {combined sound reproduction performance}.
The {combined sound reproduction performance} is written in any place of a specific {driver}, or the information that associates the {driver} with the {combined sound reproduction performance} of the {driver} is an arbitrary means. The eighth feature is that it is provided by
{Driver} as defined in claim 2 having the eighth feature.