Electrodynamic Transducer Resonator for Standing Wave Distortion
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Solution Overview
Problem
Audio signal distortion occurs in electrodynamic sound transducers due to standing waves formed between the transducer and the head plane, particularly in the audible frequency range of 5kHz - 8kHz, which affects the quality of audio reproduction in headphones.
Innovation Solution
Incorporating a resonator, designed as an acoustic absorption circuit or Helmholtz resonator, within the diaphragm of the sound transducer, with a first end having an opening at the ear-side and a closed second end, tuned to coincide with the resonant frequency of the standing wave, thereby reducing signal corruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resonator is added to reduce standing wave distortion, then audio signal quality is improved, but device complexity increases
Solution Approach 1:
The resonator is nested within the hole in the center of the diaphragm, utilizing the existing structural space rather than adding external components. This allows the resonator to be integrated into the transducer assembly without significantly increasing overall device complexity while still providing the beneficial acoustic filtering effect.
2Reliability
If the resonator volume is increased to improve standing wave cancellation, then distortion reduction is enhanced, but the transducer dimensions increase
Solution Approach 1:
The resonator is positioned locally within the central hole of the diaphragm, concentrating the acoustic filtering function in a specific region rather than distributing it throughout the entire transducer structure. This allows effective standing wave cancellation to be achieved with a compact resonator volume that does not significantly increase overall transducer dimensions.
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 resonator effectively absorbs energy at the resonant frequency, minimizing distortion and ensuring a uniform amplitude and frequency response, thus enhancing the audio quality by reducing the impact of standing waves on the sound transducer.
Implementation Method 1
a (selective) resonator, for example in the form of an acoustic notch filter or a Helmholtz resonator, is provided in this area. This resonator is dimensioned such that its resonance frequency coincides with the standing wave.
Implementation Method 2
The resonator can be designed as an acoustic notch filter or as a Helmholtz resonator.
Implementation Method 3
The resonator effectively absorbs energy at the resonant frequency, minimizing distortion
Data Source
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AI summary
The invention relates to an electrodynamic sound transducer comprising a chassis (130), a membrane (110) with a hole (150) in the center of the membrane (110), a moving coil (120), a magnetic system (140) and a resonator (200) which is placed in the hole (150) in the center of the membrane.