AMT Diaphragm With Gradient Pockets For Balanced Frequency Response
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Solution Overview
Problem
Conventional air motion transformer (AMT) acoustic transducers exhibit undesirable frequency dependency and lack a well-balanced frequency response across the human audible range, requiring multiple independent systems for treble, bass, and mid-range frequencies.
Innovation Solution
A diaphragm with alternatingly open pockets of varying width, depth, and length, where the transformation ratio of diaphragm velocity to air velocity changes continuously, allowing for a balanced and equalized frequency response across a wide range, achieved by adjusting the dimensions of pockets from one to the next.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all folds and pockets have the same dimensions in conventional AMT transducers, then the structure is simple and easy to manufacture, but the electro-acoustic transmission characteristic has undesirable frequency dependency and lacks balanced frequency response
Solution Approach 1:
The patent applies local quality by making each pocket have different dimensions from its neighbors, with at least one dimension (width, depth, or length) varying continuously across the diaphragm surface. This creates a gradient structure where pockets closer to the center have different characteristics than those at the edges, enabling continuous transformation ratio variation to achieve balanced frequency response across the entire audible spectrum.
Solution Approach 2:
The patent implements parameter changes by systematically varying the physical dimensions of pockets across the diaphragm. The width, depth, or length of pockets changes continuously from one pocket to the next, creating a gradient that transforms the velocity ratio between diaphragm and air continuously. This parameter variation enables the transducer to maintain consistent performance across different frequencies without requiring multiple independent systems.
2Manufacturing precision
If multiple independent systems are used to cover different frequency ranges, then the frequency response can be balanced, but the device complexity and size increase
Solution Approach 1:
The patent merges multiple frequency-handling functions into a single integrated diaphragm structure. Instead of using separate tweeters, mid-range drivers, and woofers, the continuous variation of pocket dimensions across one diaphragm surface enables all frequency ranges to be handled by a unified structure, reducing overall system complexity while maintaining balanced frequency response.
Solution Approach 2:
The diaphragm structure achieves multi-functionality by having each pocket contribute to different frequency ranges simultaneously. The continuous gradient of pocket dimensions allows the same diaphragm surface to handle both high and low frequencies, with each pocket's specific dimensions optimized for its local frequency contribution, making the entire structure universally capable across the audible spectrum.
3Stability of the object's composition
If pockets have uniform dimensions, then the transformation ratio is constant, but resonances occur and frequency response is unbalanced
Solution Approach 1:
The patent introduces asymmetry by making neighboring pockets have different dimensions, breaking the symmetry that causes resonances in uniform structures. The continuous variation of pocket dimensions creates an asymmetric distribution that eliminates standing wave patterns and resonant frequencies, while the gradual nature of the variation maintains structural stability and manufacturability.
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
The solution provides a compact acoustic transducer with improved frequency characteristics, capable of producing sufficient diaphragm swing for all perceivable frequencies, eliminating the need for multiple systems and minimizing resonances.
Implementation Method 1
Electric conductors are arranged on the diaphragm. An electric current through the conductors within the magnetic field between the pole plates results in a deformation of the folds
Implementation Method 2
the air filled pockets are narrowed or expanded and thereby eject or aspirate air
Data Source
AI summary
What is disclosed is a diaphragm for an acoustic AMT transducer. The diaphragm is folded such that the folds form pockets (11 . . . 15), and the pockets next to each other are alternatingly open on one and the other face of the diaphragm. The pockets (11 . . . 15) are dimensioned so that the transformation ratio of the diaphragm velocity to the velocity of the air driven by the pockets in use of the transducer varies steadily from pocket to pocket across the diaphragm. For example, the respective width, depth and/or length of the pockets increases or decreases steadily from pocket to pocket across a plurality of said pockets. The acoustic transducer comprising the diaphragm has a well-balanced frequency characteristic across a wide frequency range.