Issue |
Acta Acust.
Volume 4, Number 1, 2020
|
|
---|---|---|
Article Number | 2 | |
Number of page(s) | 10 | |
Section | Audio Signal Processing and Transducers | |
DOI | https://doi.org/10.1051/aacus/2020002 | |
Published online | 28 February 2020 |
Original Article
Correction of the Doppler distortion generated by a vibrating baffled piston
1
Sorbonne Université, S3AM Team, Laboratory STMS (UMR 9912), IRCAM-CNRS-SU, 1 Place Igor Stravinsky, 75004
Paris, France
2
CNRS, S3AM Team, Laboratory STMS (UMR 9912), IRCAM-CNRS-SU, 1 Place Igor Stravinsky, 75004
Paris, France
* Corresponding author: tristan.lebrun@ircam.fr
The Doppler effect is a phenomenon inherent to source motion, which introduces a variable propagation time between the source and a listening point. In the case of a vibrating piston, this is responsible for distortion of the radiated sound pressure. This moving-boundary phenomenon is part of the nonlinear effects involved in loudspeaker radiation. The present paper investigates the significance of this distortion, usually considered as neglectible, and addresses its correction. First, the direct problem is solved by: (a) converting the (Lagrangian) position of the moving source into its equivalent (Eulerian) velocity field at a fixed position; (b) deriving the acoustic pressure radiated from this velocity field. A series solution of (a) is derived and time-domain simulations of (b) are built from the truncated series combined with a baffled piston radiation model. Simulations show that Doppler distortion can be significant for realistic loudspeaker diaphragm motion with a wide spectral content. Second, the inverse (anti-Doppler) problem is examined, that is, the derivation of a piston displacement that generates a targeted Eulerian velocity field. The corrected piston velocity solution proves to be an uncentered signal, leading to a diverging displacement. In order to remove this practical problem, a centered approximation is preferred, based on modified inverse Volterra kernels. The anti-Doppler algorithm is reliable in the audio range.
© T. Lebrun and T. Hélie, Published by EDP Sciences, 2020
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.