A simulation study on the array control of a rectangular panel speaker for improving the sound radiation performance

Lee, Kiho; Ih, Jeong‐Guon

doi:10.1016/j.jsv.2020.115631

Cited by 6 publications

(6 citation statements)

References 23 publications

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“…After extracting the wave coefficients from the velocity responses at the field points, the transfer function can be determined between the input electric voltage of the control actuator and the coefficient of the reflected wave components. The matrix equation for generating the desired coefficients Cd of the reflected waves from the control actuators can be obtained as [10] refl,…”

Section: A Traveling-wave Control Methods (Tcm)mentioning

confidence: 99%

“…where the superscript 0 implies that the reflected waves from the boundary actually stem from the incident wave generated by the primary actuator excitation. For deriving the proper input electric voltage of the actuators to generate the desired coefficient Cd, the inverse estimation technique is employed, which is widely adopted and described in several studies on the panel speaker control [5][6][7][8][9][10][11]. The gain of the control actuators can be obtained as follows [24]- [27]:…”

Section: A Traveling-wave Control Methods (Tcm)mentioning

confidence: 99%

“…The strip speaker controlled by the TCM has the desired field that is the traveling wave field originated by the primary actuator. The desired sound from the control area is also determined by the traveling wave field as defined by (10). Therefore, the acoustic performance of the controlled strip speaker can be evaluated by comparing the resultant wave field with the desired field.…”

Section: A Evaluation Index Of Wave Field Controlmentioning

confidence: 99%

“…One can find that the radiation efficiency has some spectral troughs, which would deteriorate the acoustic performance of the speaker. The minimum volume velocity Q causes abrupt reductions in the radiation efficiency due to the hydrodynamic cancellation of the bending wave field [10]. The bending wave field of a beam controlled by the TCM creates the uni-directional traveling wave as like an infinite beam.…”

Section: Normalized Radiation Efficiencymentioning

confidence: 99%

“…To overcome this challenge, the actuators can be controlled via the direct inverse identification of the required gain; this approach can be considered a spin-off of the MCM, because it is also based on the concept of structural modes [9]. Yet another active method is the traveling-wave control method (TCM), which eliminates reflected waves from the panel boundary using phase-controlled actuators [10], [11]. This control concept is similar to those reported in previous works on the active control of structures [12]- [16], focusing on sound radiation.…”

Section: Introductionmentioning

confidence: 99%

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Use of the Normalized Design Parameters for Designing a Strip Speaker Operated by the Traveling-Wave Control Method

Lee

2022

IEEE Access

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A strip speaker is the simplified panel speaker adopting a thin beam as the radiator, which is operated under the traveling-wave control method (TCM) with three actuators. The structural resonances are suppressed fundamentally by nullifying the reflected bending waves near the boundary, thus radiating a smooth sound spectrum in a wide frequency band. This study develops the design guidelines for such TCMcontrolled strip speakers by investigating the effect of design variables on acoustic performances, such as the effective frequency range and the radiation efficiency. To this end, the acoustic performances are normalized by the size and physical properties of the beam so that a parametric study in the normalized domain can generalize the conditions for the desired acoustic performances. The result shows that the effective frequency range becomes wider when the beam material has a fast wave speed, and the radiation efficiency is enhanced as the beam density decreases. It is found that the two acoustic performances require a trade-off in selecting the actuator location and beam thickness. The suggested design procedure is validated using acrylic and aluminum beams having the same size. The aluminum beam has a faster wave speed, thus covering the effective bandwidth of 5800 Hz, 2.5 times wider than the acrylic case. On the other hand, the acrylic beam has five times higher radiation efficiency due to its low density. As a result, one can select the dimension and material of the beam appropriately to achieve the desired acoustic performance by using the suggested design method.INDEX TERMS active control, bending wave, inverse problem, sound radiation, strip speaker, traveling wave control.

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Section: A Traveling-wave Control Methods (Tcm)mentioning

confidence: 99%