Baba Banda Singh Bahadur War Memorial

The Baba Banda Singh Bahadur War Memorial at Chappar Chiri, designed by Renu Khanna & Associates, is one of the most acoustically demanding building types there is: a museum hall enclosed within a hemispherical, mound-shaped dome.

A hemisphere concentrates and refocuses sound energy toward specific focal points, producing severe echo, flutter and highly non-uniform reverberant behaviour. Flat-surface treatment methods cannot resolve it, because the problem is not how much absorption is in the room but where the geometry is sending the energy.

Concave and spherical surfaces are notorious for 'whispering-gallery' focusing effects and acoustic hot-spots. In a space like this, standard reverberation-time calculation and treatment-placement methods are effectively obsolete: a room-average figure tells you almost nothing about what a visitor standing under the crown will actually hear.

AV Acoustics took the room back to first principles, as a bespoke engineering exercise rather than a treatment schedule. The dome was modelled as a curved surface rather than a set of walls, and each position on it was assessed for where it would send arriving sound before anything was specified to go there.

• Rigorous mathematical modelling of the dome's curvature.
• Absorption and diffusion tile placement determined across the hemispherical surface tile by tile, to defeat the geometry's focusing behaviour.
• A seamless, visually unbroken finish, consistent with the memorial's solemn architectural intent.

This tile-by-tile calculation goes well beyond standard NRC-based, room-average treatment approaches, and nothing less would have produced usable, intelligible conditions in a space whose geometry actively works against conventional acoustic design. It is the kind of problem that belongs in consultancy before it reaches a contractor.

A museum hall inside a dome that can be spoken in and listened in, with no visible sign of the treatment that makes it possible. The architecture reads as the architects drew it, and the acoustic work is only apparent in the absence of the echo a dome of this shape would otherwise impose on every visitor.

Among our most technically distinguished engagements — geometry, heritage and public commemoration resolved in one surface.