Voice Coil Extension Element for Loudspeaker THD Reduction
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Solution Overview
Problem
Conventional dynamic loudspeaker drivers face reduced sensitivity and increased Total Harmonic Distortion (THD) due to voice coils needing windings placed far from the maximum magnetic field, which also limits the membrane's excursion and air pumping capacity.
Innovation Solution
A dynamic loudspeaker driver design featuring a voice coil extension element with a first and second contact surface, attached to the voice coil and membrane respectively, allowing windings to be placed within the area of maximum magnetic field intensity without increasing the voice coil's height, using materials like thermoplastics and attaching via gluing or welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the voice coil windings are placed far away from the maximum magnetic field to allow necessary excursion, then the membrane excursion is sufficient, but the sensitivity is reduced and Total Harmonic Distortion (THD) increases
Solution Approach 1:
The voice coil extension element extends the voice coil structure in the vertical dimension (away from the membrane) while keeping the windings in the horizontal plane within the magnetic field. This dimensional separation allows the windings to remain in the maximum magnetic field area for low THD while providing sufficient vertical space for membrane excursion.
2Object-generated harmful factors
If the voice coil windings are placed within the area of maximum magnetic field, then sensitivity is improved and THD is reduced, but the membrane excursion is limited
Solution Approach 1:
The extension element creates a vertical dimension that separates the functional requirements: windings remain horizontally positioned within the magnetic field for optimal acoustic performance, while the extension provides vertical space for adequate membrane excursion.
3Object-generated harmful factors
If the voice coil height is increased to allow windings within maximum magnetic field area, then sensitivity and THD improve, but the overall height of the voice coil increases
Solution Approach 1:
The extension element utilizes the vertical dimension efficiently by positioning the windings horizontally within the magnetic field while extending vertically to provide necessary space, thereby achieving optimal THD performance without excessive overall height increase.
Solution Approach 2:
The voice coil is segmented into the original voice coil portion and the extension element. This segmentation allows the windings to be concentrated in the magnetic field area while the extension portion provides structural support and space for excursion without adding proportional height to the entire assembly.
4Strength
If glue is applied directly to bond voice coil to membrane, then bonding force is sufficient, but glue overflow reduces available space for voice coil excursion
Solution Approach 1:
The voice coil extension element acts as an intermediary component between the voice coil and the membrane. It provides a bonding surface for attaching to the membrane while keeping the glue application area separate from the voice coil windings, thus maintaining bonding strength without reducing excursion space.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances acoustic performance by reducing THD and maintaining the voice coil's height, thereby improving sensitivity and air pumping capacity while minimizing unwanted distortion.
Implementation Method 1
the membrane moves with respect to the magnet system and with respect to the enclosure in response to the electric signal, resulting in moving air
Implementation Method 2
The magnet system comprises a magnet and the voice coil is operatively coupled with the magnet
Data Source
AI summary
A dynamic loudspeaker driver comprising a magnet-system; a membrane; the membrane being movably mounted with respect to the magnet-system; at least one voice coil attached to the membrane and operatively coupled with the magnet-system, wherein the voice coil comprises an upper edge facing the membrane and a lower edge being arranged opposite the upper edge of the voice coil; at least one voice coil extension element comprising an upper surface facing the membrane and a lower surface facing the upper edge of the voice coil, wherein the lower surface of the voice coil extension element is attached the upper edge of the voice coil while the upper surface of the voice coil extension element is attached to the membrane.