8th International Symposium on ElectroAcoustic Technologies
To greet the 15th Anniversary of ISEAT, the 8th ISEAT scheduled at Fall 2022.
With a combination of online and offline method, ISEAT will effectively enhance the communication and exchange of the industry, stimulate new ideas in the convergence of academic and industry between China and the rest of the world. Be part of the conference and meet digital our engineers and join their presentations. Join the ISEAT from October 29th – 30th, 2022 and discover more on the official ISEAT website!
Date: October 29th – 30th, 2022
Location: Shenzhen, China
Program overview – Please click here! (Soon available)
Registration now open – Please click here!
Our program recommendation
Modeling Balanced Armature Transducers at High Amplitudes by Wolfgang Klippel
Abstract:Electromagnetic transducers using a balanced armature play an important role in hearing aids and in-ear headphones because they generate the required sound output at high efficiency. This paper investigates the transfer behavior at high amplitudes and develops a lumped parameter model of this transducer that considers the nonlinearities caused by the geometry and material properties. This model is a basis for optimal transducer design, adjusting the armature in production and actively canceling the nonlinear distortion through nonlinear, adaptive control.
Creating Audio Products with Maximum End-User Value by Wolfgang Klippel
Abstract: The value assigned by the end-user to a loudspeaker, headphone, or any other audio device determines his purchase decision and the success of the product in the market. The paper investigates the relationship between end-user value, performance characteristics, cost structure, and the particular design. A model based on a modified benefit-cost ratio is presented that describes the impact (sensitivity) of the performance characteristics on the end-user value. Performance sensitivity is a central and powerful term in audio engineering because it links physical, perceptual, and economical quantities. This new concept is applied to all phases of the product life and addresses open questions on how to define the optimum target performance, selecting design choices, increasing the yield rate in production, and assuring reliability and quality in the final application.
Multi-Domain Transducer Measurement by Wolfgang Klippel
Abstract: Traditional loudspeaker tests measure electrical signals at the terminals and the acoustical output at a few points in the far-field under anechoic conditions. Those measurements are sufficient to derive the frequency response and the lumped transducer parameters. Modern robotics will provide new test opportunities: Near-field scanning combined with sound wave modeling and wave separation speeds up the directivity measurements and provides accurate results without using an anechoic room. A Multi-Scanning workbench applies this method to transducers mounted in a small baffle and provides simulated half-space conditions by compensating for edge reflections, acoustical shortcuts, and minimizing baffle vibration. The direct sound radiated into 3D space can be reconstructed by a few measurements in the near field exploiting the symmetry found in transducers with a round, oval or rectangular cone shape. The workbench uses robotics also for scanning mechanical vibration with a triangulation laser sensor complemented by electrical measurement. A series of tests automatically performed at a clamped device provides in a few minutes’ comprehensive assessment of the 3D sound field, linear and nonlinear lumped parameters, mechanical vibration, nonlinear distortion, and abnormal sound (rub&buzz). The robotics can be easily modified for scanning the magnetic B-field in the magnetic gap, the velocity profile at the port, and other applications. Multi-scanning brings the essential functionality of a lab into an all-in-one measurement instrument that works in almost any environment if required also at your home.
Transducer nonlinearities in active sound applications by Joachim Schlechter
Abstract: Modern DSP algorithms used for active cancellation of echoes (AEC) and noise (ANC), beam steering, 3D sounds reproduction or multi-zone contrast control model the loudspeaker and headphone used as a linear system. However, the nonlinearities inherent in the electro-acoustical transducer generate significant nonlinear distortion in the error signal of the adaptive cancelation systems of above algorithms. It becomes audible as a distorted echo, residual noise, and undesired program material in a silent zone or reduces the recognition rate of wake-up commands in smart speakers. This problem can be avoided by using more linear transducers with a larger size, lower efficiency, or higher cost. This paper investigates an alternative solution by using nonlinear control (e.g., Klippel Controlled Sound) in the DSP to actively cancel the nonlinear distortion, protect the electro-acoustical transducer against overload, and generate a desired linear overall response which is constant over product life.