Controlled coupling dual-path low-frequency enhanced sound box and electronic device

Abstract

The application relates to the technical field of audio playing equipment, and discloses a controlled coupling double-path low-frequency enhancement sound box and electronic equipment. The sound box comprises a box body, a double-diaphragm loudspeaker arranged in the box body, a front sound guide cavity, a front sound outlet, a side low-frequency coupling cavity and a passive radiator in communication with the side low-frequency coupling cavity. The active sound output of the double-diaphragm loudspeaker mainly enters the front sound guide cavity and is output outward through the front sound outlet, and the low-frequency pressure component of the double-diaphragm loudspeaker enters the side low-frequency coupling cavity to drive the passive radiator to work. The front sound guide cavity and the side low-frequency coupling cavity form a controlled coupling relationship around the same double-diaphragm loudspeaker, are separated in function and are selectively connected in acoustics.

Description

Technical Field

[0001] This invention relates to the field of audio playback device technology, and more particularly to a controlled-coupled dual-channel low-frequency enhancement speaker and electronic device. Background Technology

[0002] With the increasing popularity of portable audio devices, consumers have placed higher demands on the sound quality of small speakers, especially in terms of low-frequency performance. However, small speakers are usually limited by their physical cabinet volume, resulting in inherently insufficient low-frequency output capabilities, and they mainly face the following technical challenges.

[0003] First, the limitations of the bass reflex port solution. One existing solution uses a bass reflex structure, with a port on the cabinet, utilizing the Helmholtz resonance principle to extend the low-frequency response. However, when the cabinet size is limited, the cross-sectional area and tuning length of the bass reflex port are difficult to meet the low-frequency extension requirements, and the airflow noise from the port can significantly affect the clarity of the mid-frequency at high volumes.

[0004] Second, the shortcomings of traditional passive radiator solutions. Another type of solution uses a passive radiator instead of a port, which passively radiates low-frequency sound waves by installing a radiating diaphragm without a driving coil on the enclosure and utilizing the sound pressure within the enclosure. For example, patent publication number US8031896B2 (Bose) discloses a passive acoustic radiation system, patent publication number US20090245561A1 (Bose) discloses an acoustic passive radiation structure, and patent publication number US20140193005A1 discloses an audio speaker system with a semi-shared passive radiator. However, the above-mentioned schemes typically place the active loudspeaker and the passive radiator in the same single sealed cavity, with the active sound output path and the low-frequency loading path completely mixed in the same large cavity. This presents the following problems: First, the reaction sound pressure generated when the passive radiator resonates will be transmitted back to the active loudspeaker without obstruction, causing mid-low frequency coloration and peak-valley response near the resonant frequency; Second, there is a lack of functional distinction between the active sound output direction and the radiation direction of the passive radiator, making it difficult to balance forward clarity and low-frequency efficiency; Third, the mid-high frequency vibrations of the active loudspeaker will leak into the passive radiator path, generating unnecessary mid-frequency crosstalk.

[0005] Third, the shortcomings of the completely isolated dual-cavity design. Another type of design divides the interior of the enclosure into two completely independent cavities, one for front-firing sound and the other for low-frequency loading. However, if the two cavities are not connected at all, the same speaker cannot effectively drive the acoustic loads on both sides simultaneously through the physically isolated cavities. This results in insufficient sound pressure excitation in the low-frequency coupling cavity, the passive radiator cannot be fully driven, and the low-frequency enhancement effect is limited.

[0006] Regarding dual-diaphragm loudspeakers, patent CN115696149A (Huawei Technologies Co., Ltd.) discloses a dual-diaphragm loudspeaker and electronic device, while patent CN217546284U discloses a dual-diaphragm self-sealing loudspeaker and a speaker enclosure using the loudspeaker. However, the above solutions only focus on the vibration and sealing characteristics of the dual-diaphragm loudspeaker itself, and neither discloses a complete speaker enclosure solution that combines the dual-diaphragm loudspeaker with a front sound guide cavity and a side low-frequency coupling cavity to establish a controlled-coupled dual-path system.

[0007] In addition, patents US20060078136A1 disclose a chamber-loaded enhanced passive radiator, US20060078144A1 discloses a composite-driven enhanced passive radiator, CN105142065A discloses a thin speaker based on a snap-fit ​​passive radiator, and CN105554597B discloses a mirror-type low-frequency radiator soundbar. However, none of these solutions disclose a complete dual-path structure that uses a front acoustic chamber as the main active acoustic path and a side low-frequency coupling chamber as the low-frequency pressure branch, with controlled coupling achieved through volume, cross-sectional area, channel length, and damping parameters.

[0008] In summary, there is an urgent need in the field for a controlled coupled dual-path structure that achieves a balance between active sound clarity and low-frequency enhancement efficiency. This structure should ensure clear forward active sound output while effectively driving a passive radiator to achieve low-frequency enhancement, and simultaneously control the mutual influence between the two acoustic paths within an acceptable range, avoiding mid-low frequency coloration and peak-valley response. Summary of the Invention

[0009] The technical problem to be solved by the present invention is that: when existing small speakers use a single hybrid cavity passive radiator scheme, the active sound output path and the low frequency loading path are coupled in the same cavity, resulting in severe low frequency coloration and obvious peak-valley response in the forward sound output; while when a completely isolated dual cavity scheme is used, the low frequency enhancement effect of the passive radiator is limited due to insufficient excitation. Both existing schemes are difficult to meet the dual requirements of forward clarity and low frequency gain at the same time.

[0010] To address the aforementioned technical problems, the first aspect of this invention provides a controlled-coupled dual-path low-frequency enhancement speaker, comprising a cabinet, a dual-diaphragm speaker disposed within the cabinet, a front acoustic guide cavity, a front sound outlet, at least one side low-frequency coupling cavity, at least one passive radiator, and a low-frequency communication channel. The front acoustic radiation surface of the dual-diaphragm speaker faces the front acoustic guide cavity, and the front acoustic guide cavity is connected to the front sound outlet to form an active acoustic main path. The side low-frequency coupling cavity is connected to the passive radiator. The front acoustic guide cavity and the side low-frequency coupling cavity are separated but acoustically connected through the low-frequency communication channel. The cross-sectional area of ​​the low-frequency communication channel is smaller than the active acoustic communication cross-sectional area between the dual-diaphragm speaker and the front acoustic guide cavity.

[0011] In this invention, "controlled coupling" means that the two cavities are neither completely co-located nor completely isolated. Instead, by setting the cavity volume, low-frequency cross-sectional area, equivalent channel length, and damping parameters, the mutual influence between the two paths is kept under control. Under the premise of ensuring the clarity of the forward active sound output, the side low-frequency pressure branch is given sufficient excitation to drive the passive radiator to work.

[0012] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the side low-frequency coupling cavity includes a left low-frequency coupling cavity and a right low-frequency coupling cavity, the left low-frequency coupling cavity is connected to a left passive radiator, the right low-frequency coupling cavity is connected to a right passive radiator, and the left low-frequency coupling cavity and the right low-frequency coupling cavity are symmetrically arranged with respect to the dual-diaphragm speaker.

[0013] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the effective volume of the front acoustic cavity is 15 mL to 120 mL.

[0014] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the effective volume of the front acoustic cavity is 35 mL to 65 mL.

[0015] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the effective volume of the side low-frequency coupling cavity is 5 mL to 60 mL.

[0016] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the effective volume of the side low-frequency coupling cavity is 10 mL to 28 mL.

[0017] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the active acoustic communication cross-sectional area between the dual-diaphragm loudspeaker and the front acoustic cavity is 80mm² to 1200mm².

[0018] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the cross-sectional area of ​​the low-frequency communication channel is 20mm² to 400mm², and the ratio of the active acoustic communication cross-sectional area to the low-frequency communication channel cross-sectional area is 2:1 to 8:1.

[0019] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the equivalent channel length of the low-frequency communication channel is 5mm to 60mm.

[0020] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, a damping structure is provided in the low-frequency communication channel to limit the entry of mid-to-high frequency components into the side low-frequency coupling cavity.

[0021] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, the damping structure may optionally include at least one of open-pore foam and porous acoustic resistive film.

[0022] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, the low-frequency communication channel may optionally be a slit channel, a U-shaped folded channel, or an S-shaped folded channel.

[0023] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the damping structure is open-pore foam with a thickness of 0.5 mm to 5 mm.

[0024] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the passive radiator is provided with a counterweight, which is fixed to the center of the diaphragm of the passive radiator.

[0025] Additionally, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the counterweight is detachably connected to the center of the diaphragm of the passive radiator, the detachable connection including a threaded connection or an embedded snap-fit ​​connection. The mass of the counterweight ranges from 1g to 10g.

[0026] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the dual-diaphragm speaker includes a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are disposed opposite to each other and share the same magnetic circuit system, and at least one of them is provided with a dome protrusion facing the front acoustic cavity.

[0027] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the back of the speaker enclosure is a closed surface, without sound outlet holes, and is not used as an active sound outlet surface.

[0028] In addition, in the controlled-coupled dual-path low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the ratio of the effective volume of the front sound guiding cavity to the effective volume of the side low-frequency coupling cavity is 2:1 to 6:1.

[0029] Additionally, in the controlled-coupled dual-channel low-frequency enhancement speaker according to the first aspect of the present invention, optionally, the external dimensions of the speaker enclosure are: length 90mm to 220mm, width 50mm to 120mm, and height 40mm to 100mm.

[0030] A second aspect of the present invention provides an electronic device comprising the controlled-coupled dual-path low-frequency enhancement speaker described in the first aspect.

[0031] Compared with the prior art, the present invention has the following beneficial effects.

[0032] Firstly, the separation of active sound and low-frequency pressure functions significantly improves forward clarity. By establishing a functional division between the main active sound path (front sound guide cavity → front sound outlet) and the low-frequency pressure branch (side low-frequency coupling cavity → passive radiator), the problem of active sound being interfered with by the resonant back effect of the passive radiator when mixed in the same large cavity is avoided, thus improving the mid-to-high frequency clarity of forward sound output.

[0033] Secondly, the low-frequency excitation efficiency is improved, and the small enclosure achieves effective low-frequency enhancement. The side low-frequency coupling cavity is specifically designed to handle the low-frequency pressure component of the dual-diaphragm loudspeaker. Compared with a single hybrid cavity solution, the low-frequency pressure is more concentrated in the coupling cavity, resulting in higher excitation efficiency for the passive radiator. Under the same enclosure size, a lower effective low-frequency cutoff frequency and a flatter low-frequency response can be obtained.

[0034] Third, the controlled coupling design suppresses mid-to-low frequency coloration and peak-to-valley response. By systematically setting the volume ratio, cross-sectional area ratio, channel length, and damping parameters, the impact of the reactive sound pressure from the passive radiator resonance on the active path is limited to an acceptable range after being attenuated by the damping structure, effectively suppressing mid-to-low frequency coloration, peak-to-valley response, and transient degradation.

[0035] Fourth, fully utilize the acoustic characteristics of the dual-diaphragm loudspeaker. The dual-diaphragm loudspeaker simultaneously provides active sound output to the front acoustic chamber and low-frequency pressure components to the side low-frequency coupling chamber within a compact enclosure, achieving a dual-path design without increasing the enclosure size.

[0036] Fifth, the asymmetrical layout reduces back-side sound leakage interference. The asymmetrical layout, which features active sound emission from the front, passive radiation from the sides, and a closed back, reduces the additional mid-to-low frequency coloration caused by back-side sound leakage and wall reflections. Attached Figure Description

[0037] The invention will now be explained in further detail by way of example only with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of the overall structure of the controlled-coupled dual-path low-frequency enhancement speaker according to Embodiment 1 of the present invention. Detailed Implementation

[0039] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same parts, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the parts or the shapes of the parts may differ from the actual figures.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. The terms "comprising" and "having," and any variations thereof, referring to a process, method, system, product, or apparatus that includes or has a series of steps or units, are not necessarily limited to those explicitly listed steps or units, but may include or have other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. All methods described in this invention can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by the context.

[0041] Furthermore, the subheadings and similar terms used in the following description of this invention are not intended to limit the content or scope of this invention; they are merely for reading guidance. Such subheadings should not be construed as dividing the content of the article, nor should the content under a subheading be limited to the scope of that subheading.

[0042] This invention provides a controlled-coupled dual-path low-frequency enhancement speaker. In some examples, this controlled-coupled dual-path low-frequency enhancement speaker may also be referred to as a controlled-coupled low-frequency enhancement speaker, a dual-cavity shunt passive radiation low-frequency enhancement speaker, a dual-diaphragm speaker with an active acoustic path and a low-frequency pressure branch, or a low-frequency enhancement speaker with coordinated front-leading sound guidance and lateral passive radiation; hereinafter, it is sometimes simply referred to as a speaker. This controlled-coupled dual-path low-frequency enhancement speaker can be used in electronic devices, such as portable Bluetooth speakers, desktop speakers, digital photo frames, digital calendars, and other small audio playback devices.

[0043] In some examples, the speaker may include a cabinet 1, a dual-diaphragm loudspeaker 2 disposed inside the cabinet 1, a front sound guide cavity 31, a front sound outlet 25, at least one side low-frequency coupling cavity 32A / 32B, and a passive radiator 10A / 10B communicating with the side low-frequency coupling cavity 32A / 32B.

[0044] In some examples, the front acoustic radiation surface of the dual-diaphragm loudspeaker 2 can be positioned facing the front acoustic cavity 31. The front acoustic cavity 31 can communicate with the front sound outlet 25 to form an active acoustic main path.

[0045] In some examples, the side low-frequency coupling cavity 32A / 32B can be connected to the passive radiator 10A / 10B.

[0046] In some examples, the front acoustic cavity 31 is separated from the side low-frequency coupling cavity 32A / 32B and is acoustically connected through a low-frequency communication channel.

[0047] In some examples, the cross-sectional area of ​​the low-frequency communication channel can be smaller than the active acoustic communication cross-sectional area between the dual-diaphragm loudspeaker 2 and the front acoustic guide cavity 31. This enables frequency-selective path allocation.

[0048] The core of this invention lies in the "controlled coupling dual-path" structural design, that is, establishing two acoustic paths with different functions and selective acoustic connection around the same dual-diaphragm loudspeaker 2.

[0049] (1) Active sound main path: The dual-diaphragm loudspeaker 2 is connected to the front sound guide cavity 31, the front sound guide cavity 31 is connected to the front sound outlet 25 (forming an active sound main path), and the front sound outlet 25 is connected to the external space. This path mainly transmits mid-to-high frequency active sound, and the front sound guide cavity 31 serves as a collection and shaping cavity for active sound.

[0050] (2) Low-frequency pressure branch: The dual-diaphragm loudspeaker 2 is connected to the side low-frequency coupling cavity 32A / 32B, which is connected to the passive radiator 10A / 10B. The passive radiator 10A / 10B is connected to the external space. This path mainly transmits low-frequency pressure components. The side low-frequency coupling cavities 32A / 32B serve as low-frequency pressure collection cavities on the left and right sides, respectively, receiving the low-frequency pressure components generated by the dual-diaphragm loudspeaker and providing driving excitation for the left and right passive radiators.

[0051] The mechanism for achieving "controlled coupling" is that the front acoustic cavity 31 and the side low-frequency coupling cavities 32A / 32B are neither completely co-cavities (which would cause the passive radiator's resonant reaction to be transmitted back without obstruction, resulting in severe mid-to-low frequency coloration) nor completely isolated (which would cause the low-frequency pressure to be unable to be effectively transmitted to the side cavity, resulting in severe underexcitation of the passive radiator). Instead, by setting the cross-sectional area, channel length, and damping structure 40 of the low-frequency connecting channel, the influence between the two paths is kept within a controlled range.

[0052] In some examples, the side low-frequency coupling cavity may include a left low-frequency coupling cavity 32A and a right low-frequency coupling cavity 32B. The left low-frequency coupling cavity 32A may be connected to the left passive radiator 10A. The right low-frequency coupling cavity 32B may be connected to the right passive radiator 10B. The left low-frequency coupling cavity 32A and the right low-frequency coupling cavity 32B may be symmetrically arranged with respect to the dual-diaphragm loudspeaker 2.

[0053] In some examples, the effective volume of the front acoustic cavity 31 can be from 15 mL to 120 mL.

[0054] In some examples, the effective volume of the front acoustic cavity 31 can be from 35 mL to 65 mL.

[0055] In some examples, the effective volume of the side low-frequency coupling cavity 32A / 32B can be from 5 mL to 60 mL.

[0056] In some examples, the effective volume of the side low-frequency coupling cavity 32A / 32B can be from 10 mL to 28 mL.

[0057] In some examples, the active acoustic communication cross-sectional area between the dual-diaphragm loudspeaker 2 and the front acoustic guide cavity 31 can be from 80 mm² to 1200 mm².

[0058] In some examples, the cross-sectional area of ​​the low-frequency communication channel can range from 20 mm² to 400 mm². The ratio of the active acoustic communication cross-sectional area to the low-frequency communication channel cross-sectional area can range from 2:1 to 8:1.

[0059] In some examples, the equivalent channel length of the low-frequency connectivity channel can be from 5 mm to 60 mm.

[0060] In some examples, a damping structure 40 can be provided within the low-frequency communication channel. This restricts the entry of mid-to-high frequency components into the side low-frequency coupling cavities 32A / 32B.

[0061] In some examples, the damping structure 40 may include at least one of open-cell foam and porous acoustic membrane.

[0062] In some examples, the damping structure 40 can be open-cell foam with a thickness of 0.5 mm to 5 mm.

[0063] In some examples, the low-frequency connectivity channel is a slit channel, a U-shaped folded channel, or an S-shaped folded channel.

[0064] In some examples, the passive radiator 10A / 10B may be equipped with a counterweight 50. The counterweight 50 may be fixed to the center of the diaphragm of the passive radiator 10A / 10B. The counterweight 50 may keep the resonant frequency of the passive radiator 10A / 10B within the range of 40Hz to 120Hz.

[0065] In some examples, the counterweight 50 can be detachably connected to the center of the diaphragm of the passive radiator 10A / 10B. The detachable connection can include a threaded connection or an embedded snap-fit. The mass of the counterweight 50 can range from 1g to 10g.

[0066] In some examples, the dual-diaphragm loudspeaker 2 may include a first diaphragm 21 and a second diaphragm 22. The first diaphragm 21 and the second diaphragm 22 may be arranged opposite each other and share the same magnetic circuit system 23. At least one of the first diaphragm 21 and the second diaphragm 22 may have a dome projection facing the front acoustic cavity 31.

[0067] In some examples, the back of the enclosure 1 can be a closed surface, without a sound outlet, and not used as an active sound outlet surface.

[0068] In some examples, the ratio of the effective volume of the front acoustic cavity 31 to the effective volume of the single-sided low-frequency coupling cavity can be 2:1 to 6:1.

[0069] In some examples, the external dimensions of the housing 1 can be: length 90mm to 220mm, width 50mm to 120mm, and height 40mm to 100mm.

[0070] In some examples, the speaker may include a cabinet 1. The cabinet 1 may have external dimensions of 150mm (length) × 75mm (width) × 60mm (height). The cabinet 1 may be cuboid in shape, having six sides: front, left side, right side, top, bottom, and back. The front may have a front sound outlet 25, serving as the sound outlet for the main active sound path. The left side may house a left passive radiator 10A, and the right side may house a right passive radiator 10B. The back may be a closed mounting surface without a sound outlet. The top and bottom may house functional components such as control buttons and a charging port.

[0071] In some examples, the interior space of the enclosure 1 can be divided into three functional areas by an inner partition 60 and the mounting frame of the dual-diaphragm speaker 2. The three functional areas are the front acoustic chamber 31, the left low-frequency coupling chamber 32A, and the right low-frequency coupling chamber 32B. In this case, the three chambers can be functionally independent and acoustically selectively connected through controlled channels.

[0072] See in some examples Figure 1 The dual-diaphragm loudspeaker 2 can be installed in the central area inside the enclosure 1. In some examples, the effective diameter of the diaphragm of the dual-diaphragm loudspeaker 2 can be approximately 45 mm, the rated impedance can be 4 Ω, and the rated power can be 10 W. In some examples, the dual-diaphragm loudspeaker 2 may include a first diaphragm 21 and a second diaphragm 22. The first diaphragm 21 may have a dome protrusion facing the front acoustic chamber 31 to improve mid-to-high frequency radiation efficiency. The first diaphragm 21 and the second diaphragm 22 can be mounted opposite each other at both ends of the loudspeaker frame 24, sharing the same magnetic circuit system 23, and vibrating synchronously to generate active sound radiation. Thus, the dual-diaphragm loudspeaker 2 can simultaneously provide active sound output to the front acoustic chamber 31 and provide a low-frequency pressure component to the side low-frequency coupling chamber.

[0073] In some examples, the speaker enclosure may include a front acoustic chamber 31. The front acoustic chamber 31 may be formed by the inner front wall of the enclosure 1, the front side of the dual-diaphragm speaker 2, and the inner partition 60. In some examples, the effective volume of the front acoustic chamber 31 may be approximately 50 mL. In some examples, the active acoustic communication cross-sectional area may be approximately 350 mm². In some examples, the opening area of ​​the front sound outlet 25 may be approximately 200 mm², a single circular hole with a diameter of approximately 16 mm. The opening area of ​​the front sound outlet 25 may be smaller than the active acoustic communication cross-sectional area, creating an appropriate sound pressure build-up effect within the front acoustic chamber 31. This improves the forward sound emission efficiency.

[0074] In some examples, the speaker enclosure may include a side low-frequency coupling cavity. The side low-frequency coupling cavity may include a left low-frequency coupling cavity 32A and a right low-frequency coupling cavity 32B. The left low-frequency coupling cavity 32A and the right low-frequency coupling cavity 32B may be located on the left and right sides of the dual-diaphragm speaker 2, respectively. The side low-frequency coupling cavity may be formed by the inner partition 60, the side of the speaker frame 24, and the left / right inner walls of the enclosure 1. In some examples, the effective volume on one side may be approximately 18 mL, the low-frequency communication cross-sectional area may be approximately 80 mm², and the equivalent channel length may be approximately 15 mm. In some examples, an open-cell polyurethane foam with a thickness of approximately 2 mm may be provided within the low-frequency communication channel as a damping structure 40, with a flow resistance coefficient of approximately 1500 Pa·s / m. This restricts the entry of mid-to-high frequency components into the side low-frequency coupling cavity.

[0075] In some examples, the speaker enclosure may include passive radiators 10A and 10B. The effective diameter of the diaphragms of passive radiators 10A and 10B may be approximately 50 mm. In some examples, passive radiators 10A and 10B may be fitted with a counterweight of approximately 5 g, with a resonant frequency of approximately 70 Hz. The effective diaphragm area of ​​the passive radiators may be approximately 1.2 times the effective area of ​​the active diaphragm of the dual-diaphragm loudspeaker 2. This allows the passive radiators to efficiently radiate low-frequency sound waves around 70 Hz.

[0076] In some examples, the controlled coupling parameters are combined as follows: The effective volume of the front acoustic cavity 31 is 50 mL, and the effective volume of the single-sided low-frequency coupling cavity is 18 mL, with a volume ratio of approximately 2.8:1. The active acoustic communication cross-sectional area is 350 mm², and the low-frequency communication cross-sectional area is 80 mm², with an area ratio of approximately 4.4:1. The equivalent channel length is 15 mm, and the damping structure 40 has a thickness of 2 mm. In this case, the above parameter combination satisfies the controlled coupling conditions, achieving frequency-selective path allocation.

[0077] In some examples, after the dual-diaphragm speaker 2 is driven, the forward active sound is collected through the front sound guide cavity 31 and radiated forward through the front sound outlet 25, resulting in good mid-to-high frequency clarity. The low-frequency pressure component enters the left and right side low-frequency coupling cavities 32A / 32B through a low-frequency communication channel with a cross-sectional area of ​​approximately 80 mm² and a 2 mm thick perforated foam damping structure 40. The left and right passive radiators 10A / 10B efficiently radiate low-frequency sound waves near the resonant frequency of approximately 70 Hz, achieving an effective low-frequency enhancement effect. Compared with the traditional single-cavity passive radiator scheme of the same size, it can significantly reduce the low-frequency cutoff frequency and significantly improve the mid-to-high frequency flatness.

[0078] In some examples, this embodiment can be designed for portable applications, enabling a controlled-coupled dual-path structure within a smaller housing 1. The external dimensions of housing 1 can be 95mm (length) × 55mm (width) × 45mm (height).

[0079] In some examples, the effective diameter of the diaphragm of the dual-diaphragm loudspeaker 2 can be approximately 30 mm, with a rated impedance of 4 Ω and a rated power of 5 W. The first diaphragm 21 may have a dome protrusion facing the front acoustic cavity 31.

[0080] In some examples, the effective volume of the front acoustic cavity 31 can be approximately 22 mL, and the active acoustic cross-sectional area is approximately 180 mm². The front sound outlet 25 can be a single circular hole with a diameter of approximately 12 mm and an opening area of ​​approximately 113 mm².

[0081] In some examples, the effective volume of a single-sided low-frequency coupling cavity can be approximately 10 mL, the low-frequency communication cross-sectional area is approximately 45 mm², and the equivalent channel length is approximately 10 mm. The damping structure 40 can be an open-cell foam with a thickness of 1.5 mm. The volume ratio is approximately 2.2:1, and the cross-sectional area ratio is approximately 4:1.

[0082] In some examples, the effective diameter of the diaphragm of passive radiators 10A and 10B can be approximately 35 mm, the counterweight 50 approximately 3 g, and the resonant frequency approximately 90 Hz. In this case, due to the further reduction in the size of the enclosure 1, the resonant frequency of the passive radiators is set higher to prioritize mid-to-high frequency clarity. Compared to a single-cavity solution of the same size, the low-frequency cutoff frequency can be reduced by approximately 8 Hz to 15 Hz.

[0083] In some examples, the invention can also be applied to desktop speaker scenarios to enhance low-frequency response within a larger enclosure. The enclosure 1 can have external dimensions of 200mm (length) × 100mm (width) × 80mm (height).

[0084] In some examples, the effective diameter of the diaphragm of the dual-diaphragm loudspeaker 2 can be approximately 55 mm, with a rated power of 20 W. In some examples, the effective volume of the front acoustic chamber 31 can be approximately 85 mL, and the active acoustic cross-sectional area can be approximately 600 mm². The front sound outlet 25 can be a porous mesh structure with a total opening area of ​​approximately 350 mm².

[0085] In other examples, the effective volume of the single-sided low-frequency coupling cavity can be approximately 28 mL, the low-frequency communication cross-sectional area is approximately 150 mm², and the equivalent channel length is approximately 25 mm. The damping structure 40 can be a folded channel type, with the channel designed as a U-shaped folded structure, and the equivalent length is approximately three times the straight-line distance. In other examples, the folded channel can also be filled with open-pore foam with a thickness of approximately 1 mm to further improve the mid-to-high frequency cutoff effect.

[0086] In some examples, the effective diameter of the diaphragm of passive radiators 10A and 10B can be approximately 60 mm, the counterweight 50 is approximately 8 g, and the resonant frequency is approximately 55 Hz. In this case, the low-frequency cutoff frequency can be as low as approximately 45 Hz to 50 Hz, resulting in a significant low-frequency response. Therefore, it is suitable for desktop applications with high requirements for low frequencies.

[0087] In other examples, the damping structure 40 can be an acoustic damping foam type. The acoustic damping foam type can be filled with open-cell polyurethane foam within the low-frequency communication channel, with pore diameters ranging from 0.1 mm to 0.5 mm and thicknesses from 1 mm to 5 mm. In some examples, the flow resistance coefficient can be from 500 Pa·s / m to 5000 Pa·s / m. Thus, it is possible to achieve customized acoustic characteristics by replacing foams of different densities.

[0088] In other examples, the damping structure 40 can be a porous acoustic resistive membrane. The porous acoustic resistive membrane can have a stainless steel microporous filter or polyester nonwoven fabric installed at the inlet of the low-frequency communication channel. In some examples, the pore size can be from 0.05 mm to 0.3 mm, and the porosity can be from 20% to 60%. This allows for precise control of the acoustic resistance by adjusting the porosity.

[0089] In other examples, the damping structure 40 can be a slit channel type. The slit channel type allows the low-frequency connecting channel to be designed as a rectangular slit with a cross-sectional width of 0.5 mm to 2 mm. In some examples, damping control is achieved by utilizing the high resistance characteristics of the narrow slit to viscous flow. This allows for a one-piece molded structure design without the need for additional materials.

[0090] In other examples, the damping structure 40 can be a folded channel type. The folded channel type allows the low-frequency communication channel to be designed as an S-shaped or U-shaped folded structure, with an equivalent channel length of 2 to 4 times the straight-line distance. In other examples, acoustic damping foam can also be filled within the folded channel, achieving a combination of the two solutions. In this case, a stronger low-pass cutoff effect is achieved for mid-to-high frequency components. Therefore, it is suitable for products with high requirements for low-frequency extension.

[0091] The side leakage suppression at the mid-frequency (1kHz) corresponding to the above schemes is approximately 6dB, 8dB, 10dB, and 12dB, respectively. The transmission loss at the low-frequency (100Hz) is approximately 0.5dB, 0.8dB, 1.2dB, and 1.5dB, respectively. Each scheme achieves a reasonable balance between effective low-frequency transmission and mid-frequency suppression.

[0092] In some examples, passive radiators 10A and 10B may include a counterweight 50. The counterweight 50 can be fixed to the center of the passive radiator diaphragm to adjust the resonant frequency of the passive radiator. In some examples, an M3 threaded mounting hole can be provided in the center of the passive radiator diaphragm, and the counterweight 50 is screwed in and fixed by an M3 screw. This makes installation convenient and reliable.

[0093] In some examples, the counterweight 50 can preferably be made of a copper disc, which has high density and small size. In some examples, the weight of the counterweight 50 can be 1g to 3g, corresponding to a resonant frequency of approximately 90Hz to 120Hz, suitable for products prioritizing clarity. In other examples, the weight of the counterweight 50 can be 4g to 6g, corresponding to a resonant frequency of approximately 65Hz to 90Hz, suitable for balanced products. In still other examples, the weight of the counterweight 50 can be 7g to 10g, corresponding to a resonant frequency of approximately 45Hz to 65Hz, suitable for products prioritizing low-frequency response.

[0094] In some examples, the mass of the counterweight 50 is chosen so that the resonant frequency of the passive radiator is close to the Helmholtz acoustic resonant frequency of the side low-frequency coupling cavity. In some examples, the difference between the two resonant frequencies can be controlled within ±15 Hz. In this case, the maximum low-frequency radiation efficiency and the flattest low-frequency response curve can be obtained. This avoids the low-frequency response double peaks or response gaps caused by the two resonant frequencies being too far apart.

[0095] While the invention has been specifically described above in conjunction with the accompanying drawings and examples, it is to be understood that the above description does not limit the invention in any way. Those skilled in the art can make modifications and variations to the invention as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the invention.

Claims

1. A controlled-coupled dual-path low-frequency enhancement speaker, comprising a cabinet (1), a dual-diaphragm loudspeaker (2) disposed inside the cabinet (1), a front sound guide cavity (31), a front sound outlet (25), at least one side low-frequency coupling cavity, at least one passive radiator, and a low-frequency communication channel, characterized in that, The front acoustic radiation surface of the dual-diaphragm loudspeaker (2) is arranged facing the front acoustic guide cavity (31), and the front acoustic guide cavity (31) is connected to the front sound outlet (25) to form an active acoustic main path. The side low-frequency coupling cavity is connected to the passive radiator; The front acoustic cavity (31) is separated from the side low-frequency coupling cavity and is acoustically connected through the low-frequency communication channel; The cross-sectional area of ​​the low-frequency communication channel is smaller than the active acoustic communication cross-sectional area between the dual-diaphragm loudspeaker (2) and the front acoustic cavity (31).

2. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The side low-frequency coupling cavity includes a left low-frequency coupling cavity (32A) and a right low-frequency coupling cavity (32B). The left low-frequency coupling cavity (32A) is connected to the left passive radiator (10A), and the right low-frequency coupling cavity (32B) is connected to the right passive radiator (10B). The left low-frequency coupling cavity (32A) and the right low-frequency coupling cavity (32B) are symmetrically arranged with respect to the dual-diaphragm loudspeaker (2).

3. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, A damping structure (40) is provided in the low-frequency communication channel to restrict the entry of mid-to-high frequency components into the side low-frequency coupling cavity.

4. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 3, characterized in that, The damping structure (40) includes at least one of open-cell foam and porous acoustic membrane.

5. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The low-frequency communication channel is a slit channel, a U-shaped folded channel, or an S-shaped folded channel.

6. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The passive radiator is provided with a counterweight (50), which is fixed to the center of the diaphragm of the passive radiator.

7. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The ratio of the active acoustic communication cross-sectional area to the low-frequency communication channel cross-sectional area is 2:1 to 8:

1.

8. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The dual-diaphragm loudspeaker (2) includes a first diaphragm (21) and a second diaphragm (22), the first diaphragm (21) and the second diaphragm (22) are arranged opposite to each other and share the same magnetic circuit system (23), and at least one of them has a dome protrusion facing the front sound guide cavity (31).

9. The controlled-coupled dual-path low-frequency enhancement speaker according to claim 1, characterized in that, The back of the enclosure (1) is a closed surface, without sound holes, and is not used as an active sound output surface.

10. An electronic device, characterized in that, The controlled-coupled dual-path low-frequency enhancement speaker includes any one of claims 1 to 9.

Images