From concert halls to noise barriers : attenuation from interference gratings

Davies, WJ

Abstract

The seat dip effect is a low-frequency attenuation affecting sound travelling at grazing incidence over seating in auditoria. It is caused by scattered sound from the seats interfering with sound travelling directly from the source on the stage. In outdoor noise control, the simple single noise barrier gives good attenuation at high frequencies, but is limited by diffraction at low frequencies. This paper presents some results from an attempt to exploit seat dip attenuation as a tool to control outdoor noise propagation. Boundary element calculations are used to explore the effects of multiple low barriers, trenches, scaling and geometry.

Citation

Davies, W. (2002, March). From concert halls to noise barriers : attenuation from interference gratings. Presented at Acoustics 2002, Salford, Greater Manchester

• Presentation Conference Type: Other
• Conference Name: Acoustics 2002
• Conference Location: Salford, Greater Manchester
• Start Date: Mar 25, 2002
• End Date: Mar 27, 2002
• Publication Date: Mar 25, 2002
• Deposit Date: Dec 3, 2012
• Publicly Available Date: Apr 5, 2016
• Keywords: seat dip barrier
• Additional Information: Event Type : Conference; References : [1] G M SESSLER & J E WEST, ‘Sound transmission over theater seats,’ J. Acoust. Soc. Am., 36 p1725-1732 (1964). [2] T J SCHULTZ & B G WATTERS, ‘Propagation of sound across audience seating,’ J. Acoust. Soc. Am., 36 p885-896 (1964). [3] W J DAVIES & T J COX, ‘Reducing seat dip attenuation,’ J. Acoust. Soc. Am. 108 p2211-2218 (2000). [4] J S BRADLEY, ‘Some further investigations of the seat dip effect,’ J. Acoust. Soc. Am., 90 p324-333 (1991). [5] W J DAVIES & Y W LAM, ‘New attributes of seat dip attenuation,’ Applied Acoustics, 41 p1-23 (1994). [6] K ISHIDA, K SUGINO & I MASUDA, ‘On the sound reflection of the auditorium seats,’ Proc. 13th I.C.A., 2 p157-160, Belgrade (1989). [7] E MOMMERTZ, ‘Some measurements of the propagation of acoustic-waves skimming over the public and seats,’ Acustica, 79 42-52 (1993). [8] W J DAVIES, T J COX & Y W LAM, ‘Subjective perception of seat dip attenuation,’ Acustica, 82 p784-792 (1996). [9] Y ANDO, M TAKAISHI & K TADA, ‘Calculations of the sound transmission over theater seats and methods for its improvement in the low-frequency range,’ J. Acoust. Soc. Am., 72 p443-448 (1982). [10] L A M VAN DER HEIJDEN & M J M MARTENS, ‘Traffic noise reduction by means of surface wave exclusion above parallel grooves in the roadside,’ Applied Acoustics, 15 p329-339 (1982). [11] T TERAI, ‘On the calculation of fields around three-dimensional objects by integral equation methods,’ J. Sound Vib., 69 p71-100 (1980). [12] H A SCHENEK, ‘Improved integral formulation for acoustic radiation problems, J. Acoust. Soc. Am., 44 p41-58 (1968).