Physics-based spring reverb emulation has seen steady advances in the literature over approximately the past decade, with a recent focus on improved numerical simulation of helical spring vibrations. The input and output of tanks have not yet seen extensive research, and as such simplified driving and pick-up models are commonly employed in simulation algorithms. To help advance the physics-based models, this study investigates the underlying physics behind the driving mechanism, the design of which is based on electromagnetic induction and includes a cylindrical magnet attached to the spring. How the electromagnetic field drives this magnetic bead is studied here experimentally. It is generally thought that the bead drives the spring through rotation, but specific aspects still require attention, including if the magnetic field can excite other polarisations and how the behaviour varies across the audio frequency range. Using sine-sweeps and high-speed video recordings, two polarisations of motion evident in the bead are tracked up to 1,000 Hz, where the effect of the spring is mitigated with damping. Video footage compares the damped and undamped case and indicates that the transverse motion is due to the reflected wave propagations and the magnetic field thus induces only rotation in the bead.
|Name||Proceedings of Meetings on Acoustics|
|Publisher||Accoustical Society of America|