Distributed Mode Loudspeaker Transducer Layout Against Rocking Motion

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Solution Overview

Problem

High power distributed mode loudspeakers experience persistent rocking motion at lower pistonic frequencies, which can cause physical damage to the voice coil, due to the mechanical resonance and bending wave vibrations, especially when operating in high power applications.

Innovation Solution

The solution involves an asymmetric placement of audio transducers on the panel, with specific coordinates in the X-direction and Y-direction relative to the center, to minimize force moments and reduce non-axial displacements, combined with a honeycomb structure and optimized magnetic field design to stabilize the transducers and prevent rocking motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transducers are placed symmetrically on the panel to achieve balanced sound distribution, then sound uniformity is improved, but rocking motion occurs at high power causing transducer damage

Engineering Contradiction:
Improvetransducer stabilityVSAvoidrocking motion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetric placement of transducers on the panel, specifically positioning them at non-symmetric coordinates (e.g., first transducer at x1, y1; second transducer at x2, y2 where the positions are not mirror images). This asymmetry creates a stabilizing effect that counteracts the rocking motion generated during high-power operation, while still maintaining adequate sound distribution across the panel surface.

Inventive Principle:
Principle #4Asymmetry

2Power

If transducers are positioned to maximize pistonic vibration at low frequencies, then low frequency sound output is improved, but non-axial displacements increase causing voice coil damage

Engineering Contradiction:
Improvelow frequency sound outputVSAvoidnon-axial displacements
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent employs local quality by assigning specific, optimized coordinates to each transducer based on its individual position and function. Each transducer is placed at a predetermined location (x1, y1), (x2, y2), etc., where the coordinates are specifically calculated to minimize non-axial displacements while maintaining effective pistonic vibration. This localized optimization allows each transducer to operate in its optimal position rather than using a uniform placement pattern.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple transducers are used to increase power handling and modal distribution, then frequency coverage is improved, but the complexity of achieving stable operation increases

Engineering Contradiction:
Improvefrequency coverageVSAvoidtransducer positioning complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and pre-positioning the transducers at specific coordinates before operation. The optimal positions (x1, y1), (x2, y2), etc., are determined in advance through design and analysis, allowing the system to achieve stable high-power operation without requiring complex real-time adjustments or controls during operation.

Inventive Principle:
Principle #10Preliminary action

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 approach effectively reduces physical damage to the transducers by minimizing non-axial displacements and maintaining efficient sound distribution across the operational frequency range, ensuring stable operation even at high power levels.

Implementation Method 1

each cone shaped element is mechanically driven on one end in a piston-like manner (i.e., 'pistonic') with the use of a moving coil that employs an electromagnetic drive means

Methodology Applied
Scientific EffectElectromagnetic drive: Electromagnetic Induction

Implementation Method 2

They rely on exploiting the mechanical resonance of the panels used in these loudspeakers

Methodology Applied
Scientific EffectMechanical resonance: Resonance

Implementation Method 3

These types of loudspeakers have come to be referred to as 'distributed mode loudspeakers' since they rely on exploiting the mechanical resonance of the panels used in these loudspeakers. In addition to their ability to generate sound relying upon mechanical resonance, such distributed mode loudspeakers are novel because of their use of materials that are capable of sustaining bending waves

Methodology Applied
Scientific EffectBending waves: Vibration

Data Source

PatentEP3248390B1Audio transducer stabilization system and method
Publication Date: 2022.08.10 TECTONIC AUDIO LABS INC
  • EP3248390B1 patent drawingFigure 1A~1B
  • EP3248390B1 patent drawingFigure 1C
  • EP3248390B1 patent drawingFigure 1D~1E

AI summary

System and method for audio transducer stabilization comprising providing a sound generation panel for transmission of audio sound waves in response to a plurality of force inputs received from three or more audio transducers, providing a mounting frame for coupling to the sound generation panel, the mounting frame having three or more predefined locations for receiving audio transducers, placing the three or more audio transducers in the predefined locations, the predefined locations optimized to reduce a plurality of force moments when the audio transducers are driven using an input drive signal, connecting a coupler ring on each of the audio transducers placed in the predefined locations on the mounting frame to an outer surface of the sound generation panel, and driving each of the audio transducers using the input drive signal from an audio amplifier.