Preliminary experimental evaluation of a novel loudspeaker featuring magnetorheological fluid surround absorber

Abstract

<span>A novel design of magnetorheological fluids (MRF) based surround device in a loudspeaker system was studied in this article. The main objective of this research is to design a new surround device of the loudspeaker that can be easily controlled its damping. Therefore, it was predicted that the audio pressure level on the loudspeaker could be easily manipulated at a different sound source by applying a certain magnetic field. This function could not be reached using one conventional speaker system. Firstly, a set of an electromagnetic device containing MRF was designed to replace the conventional rubber surround. The magnetic circuit was then evaluated using the finite element method magnetics to study the flux distribution in the MRF area. The current was varied from 0.25 to 0.75 A by an interval of 0.25 A. The magnetic flux resulted from the simulation was then logged and used as the based value for predicting the change of shear yield stress. The base properties of the shear yield stress of the MRF against the magnetic flux was obtained from previous experimental result. Therefore, it was hopefully the prediction could be closed to the real system. Based on the simulation result, the shear yield stress varied from 43 to 49 Mpa or about 15 % increment. </span><span lang="IN">A simple experimental work was carried out. By applying particular direct current into the coil, the sound quality generated by the loudspeaker shows different values</span><span>.</span><span lang="IN"> Based on the preliminary experiment, the level of decibel decreased about 3 dB as the application of magnetic fields. The idea has been proven in this preliminary experimental evaluation.</span>

Conducting and Magnetic Composites Polypyrrole Nanotubes/Magnetite Nanoparticles: Application in Magnetorheology

“…On the other hand, the particles have a high potential to be used as an additive in conventional magnetorheological suspensions in so-called bimodal systems due to their mild magnetic properties and morphology, which can increase overall performance of suspensions, such as enhanced sedimentation stability and redispersibility, ,, which will be further investigated. On the other hand, magnetorheological suspensions with similar effects as presented in this study can be used in various applications such as audio speakers where the high level of effect is not demanded …”

“…On the other hand, magnetorheological suspensions with similar effects as presented in this study can be used in various applications such as audio speakers where the high level of effect is not demanded. 53…”

Effect of Time and Frequency of Magnetic Field Application on MRF Pressure Performance

“…Various research articles and studies that take advantage of the potential of MRF continue to be carried out, for example, with regard to shock absorbers [7,[10][11][12][13], brakes [14][15][16], valves [12,[17][18][19], polishing [20][21][22], haptic devices [23][24][25], mounts [26][27][28], and sound propagation [29,30].…”