Local Active Sound Control Using 2-Norm and ∞-Norm Pressure Minimization

Tseng, Wen-Kung; Rafaely, Boaz; Elliott, Stephen J.

doi:10.1006/jsvi.1999.2889

Cited by 19 publications

(20 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, in a modally dense acoustic environment, global control quickly becomes impractical as the number of required secondary sources increases approximately in proportion to the cube of the excitation frequency [5]. As a result of this physical limitation, active control in large enclosures is often limited to controlling the sound field in a specific local region and a significant amount of research has been conducted in this area [2,20,21,22,23]. For a local active control system employing a single error sensor and remote secondary source and operating in a diffuse sound field, it has been shown that the diameter of the zone of quiet within which 10 dB of attenuation is achieved is limited to about one tenth of the acoustic wavelength [22].…”

Section: Feedforward Active Noise Control Systemmentioning

confidence: 99%

Active noise control of a diesel generator in a luxury yacht

Cheer

Elliott

2016

Applied Acoustics

View full text Add to dashboard Cite

Active noise control has been applied to a variety of systems in order to improve performance without the increases in size and weight that would otherwise be required by traditional passive noise control treatments. This paper investigates the application of an active noise control system to the control of generator noise in the master cabin of a luxury yacht. A multichannel, multi-tonal active noise control system employing loudspeakers and microphones in the master cabin of the yacht is investigated. It is shown that, due to the high number of engine orders produced by the generator, in order to achieve significantly perceptible levels of noise attenuation it is necessary to control at least 7 individual orders. A controller is investigated which targets 19 engine orders and it is shown to achieve in excess of 5 dB broadband attenuation, whilst achieving up to 23 dB attenuation in individual orders. This corresponds to a 23% reduction in the Zwicker loudness.

show abstract

Section: Feedforward Active Noise Control Systemmentioning

confidence: 99%

Active noise control of a diesel generator in a luxury yacht

Cheer

Elliott

2016

Applied Acoustics

View full text Add to dashboard Cite

show abstract

“…A common problem is a rapid drop of performance with increasing distance from the control points 25,26 . This can be alleviated by controlling both pressure and pressure gradient 27,28 , adding sensors 25,29 , preconditioning room responses (smoothing) 30 , or geometrical optimization to improve the match between the direct and reflected wavefronts at the control points 31 . The last method offers the most practical benefits, as it may improve attenuation away from the control locations without additional equipment or signal processing.…”

Section: A Identification Of a Suitable Control Strategymentioning

confidence: 99%

Optimal source placement for sound zone reproduction with first order reflections

Olik

Jackson

Coleman

et al. 2014

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

The problem of delivering personal audio content to listeners sharing the same acoustic space has recently attracted attention. It has been shown that a perceptually acceptable level of acoustic separation between the listening zones is difficult to achieve with active control in non-anechoic conditions. A common problem of strong first order reflections has not been examined in detail for systems with practical constraints. Acoustic contrast maximization combined with optimization of source positions is identified as a potentially effective control strategy when strong individual reflections occur. An analytic study is carried out to describe the relationship between the performance of a 2×2 (two sources and two control sensors) system and its geometry in a single-reflection scenario. The expression for acoustic contrast is used to formulate guidelines for optimizing source positions, based on three distinct techniques: Null-Split, Far-Align, and Near-Align.The applicability of the techniques to larger systems with up to two reflections is demonstrated using numerical optimization. Simulation results show that optimized systems produce higher acoustic contrast than non-optimized source arrangements and an alternative method for reducing the impact of reflections (sound power minimization).

show abstract

“…In this work two and three monopoles are used as the secondary fields and a microphone is placed at the (0.1 m, 0) point, i.e., 10cm from the origin. The reason for choosing this configuration is because the previous study on pure tone and broad-band diffuse fields used the same configuration [Ross, 1980;Joseph, 1990;Tseng, 1999Tseng, , 2000Tseng, , 2009Rafaely, 2000Rafaely, , 2001Chun et al, 2003]. A series of examples are performed to analyze the quiet zones in pure tone and broadband diffuse fields.…”

Section: Quiet Zone Analysis In Pure Tone and Broad-band Diffuse Fieldsmentioning

confidence: 99%

“…Although cancelling the noise at many points could produce larger zones of quiet, the optimal spacing between cancellation points varies with frequency [Miyoshi et al, 1994;Guo et al, 1997]. Previous work on active control of diffuse fields investigated the performance of pressure attenuation for single-tone diffuse field only which was produced by single frequency [Ross, 1980;Joseph, 1990;Tseng, 1999Tseng, , 2000. Recent work on broad-band diffuse fields only concentrated on analysis of auto-correlation and cross-correlation of sound pressure [Rafaely, 2000[Rafaely, , 2001Chun et al, 2003].…”

Section: Introductionmentioning

confidence: 99%

“…Previous work on active control of diffuse fields investigated the performance of pressure attenuation for single-tone diffuse field only which was produced by single frequency [Ross, 1980;Joseph, 1990;Tseng, 1999Tseng, , 2000. Recent work on broad-band diffuse fields only concentrated on analysis of auto-correlation and cross-correlation of sound pressure [Rafaely, 2000[Rafaely, , 2001Chun et al, 2003]. However there is only some work related to active control of broad-band diffuse fields [Tseng, 2009].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of Quiet Zones in Diffuse Fields

Tseng¹

2012

Noise Control, Reduction and Cancellation Solutions in Engineering

View full text Add to dashboard Cite

The wave model of pure tone and broad-band diffuse sound fieldsGarcia-Bonito used the wave model for a pure tone diffuse field, which is comprised of large number of propagating waves arriving from various directions [Garcia et al., 1997]. However, a complete mathematical derivation of this model, which was taken from Jacobson [Jacobsen, 1979], was not found and the wave model of broadband diffuse sound fields has not been derived. For completeness, this mathematical derivation for pure tone and broadband diffuse fields is given below. When a source produces sound in an enclosure in a room, the sound field is composed of two fields. One is the sound field radiated directly from the source called the direct sound www.intechopen.com Noise Control, Reduction and Cancellation Solutions in Engineering 48field. The other is reflection of sound waves from surfaces of the room, which contributes to the overall sound field, this contribution being known as the reverberant field. Therefore at any point in the room, the sound field is a function of direct and reverberant sound fields. The sound field in a reverberant space can be divided into two frequency ranges. In the low frequency range, the room response is dominated by standing waves at certain frequencies. In the high frequency range, the resonances become so numerous that they are difficult to distinguish from one another. For excitation frequencies greater than the Schroeder frequency, for which M () = 3, where M() is the modal overlap [Garcia et al., 1997], the resulting sound field is essentially diffuse and may be described in statistical terms or in terms of its average properties. The diffuse sound field model can be derived as follows. In the model described below, the diffuse field is comprised of many propagating waves with random phases, arriving from uniformly distributed directions. Although the waves occupy a three-dimensional space, the quiet zone analysis is performed, for simplicity, over a two-dimensional area. Consider a single incident plane wave travelling along line r with its wave front parallel to lines A and B as shown in Figure 1. We assume that the plane wave has some phase when approaching line A, and has some phase shift due to the time delay when approaching line B both on the x-y plane. We next find the phase of the plane wave at (x 0 ,y 0 ) on line B. We now consider the plane perpendicular to lines A and B and parallel to line r, as illustrated in Figure 2. This incident plane wave has phase shift when approaching point (x 0 ,y 0 ) on line B. The pressure at this point can therefore be expressed as P (x 0 ,y 0, k) = (a+jb) exp (-jkd) ( 1) where a+jb account for the amplitude and phase of this incident plane wave when approaching line A, k is the wave number and d is the additional distance travelled by the plane wave when approaching point (x 0 ,y 0 ) on line B as shown in Figure 2. The equation of line A on the x-y plane can be written asThe equation of line B on x-y plane can also be written aswhere m is the distance between li...

show abstract

Local Active Sound Control Using 2-Norm and ∞-Norm Pressure Minimization

Cited by 19 publications

References 7 publications

Active noise control of a diesel generator in a luxury yacht

Active noise control of a diesel generator in a luxury yacht

Optimal source placement for sound zone reproduction with first order reflections

Analysis of Quiet Zones in Diffuse Fields

Contact Info

Product

Resources

About