The Sound of Spaces: Understanding Acoustics in Architecture

Kalani from Sculptform welcomes attendees to the 'Sound of Spaces' webinar, highlighting its journey from an in-person to a virtual event. She briefly introduces Sculptform's product range, specifically their 'click on batten system' with an integrated acoustic backing, and outlines the agenda: Peter Holmes on acoustics in architecture, and Ben Percy on a case study focusing on educational acoustics.

Kalani details Sculptform's Australian-owned manufacturing of feature walls, ceilings, and facade systems. She focuses on their click-on batten system, explaining its three components (track, clips, battens) and its design for seamless integration of a 7mm acoustic backing. This feature aids designers in meeting acoustic requirements and enhancing space functionality, as demonstrated in projects like Her Majesty's Theatre in Adelaide and the Huntington Tower School of Performing Arts.

Dr. Peter Holmes of Inhabit Group is introduced, highlighting his extensive experience in acoustics and theatre consultancy on iconic projects. He begins his presentation on understanding how sound relates to architecture, emphasizing designing for human experience and the aesthetic discipline of sound.

Peter explains that sound in architecture is either a result of well-designed integration or an accidental consequence. He likens sound to a visual aesthetic, where building geometry and materials form both visual and acoustic aspects. He discusses specialized spaces like anechoic and reverberant chambers to illustrate extremes and the need to tailor acoustic design to the function and occupation of a space for productivity and wellness.

Peter emphasizes that acoustic considerations should be integrated from the planning and concept stages. He provides examples like modern library hubs (combining noisy and quiet activities) and large, reverberant airports where clear communication is vital. He explains the distinction between designing for natural acoustics (concert halls) versus more intimate or amplified spaces (playhouses, stadia), and the historical context of acoustic design traced back to Wallace Clement Sabine's work on reverberation.

Peter illustrates reverberation by describing how sound radiates and reflects in a room, building up a decay of sound. He introduces the concept of sound having a 'color' similar to light, and how different materials react to the sound spectrum. He critiques the oversimplification of complex acoustic data into single numbers (like RW, NRC) and advocates for a more nuanced understanding of sound's spectral variations, akin to a painter's color palette.

Peter explains how different materials (timber, perforated panels, carpet) act as sound filters, each contributing a unique 'color' to the sound in a space. He draws parallels with mixing consoles and how architects' material choices influence the overall sound quality. He stresses that designing for a deliberate acoustic outcome, harmonious with the visual design, requires early engagement and understanding of how materials affect sound transparency and reflection.

Peter discusses the challenges of communicating abstract acoustic properties compared to visual aesthetics. He reiterates that successful acoustic design requires an integrated response to function and occupation, with early engagement being critical. He advises bringing in acoustic consultants during feasibility or very early concept stages, even for seemingly minor projects, to prevent costly design revisions later on, highlighting the differences in a project's acoustic needs.

Ben Percy, Associate Director at Baldasso Cortese, is introduced, known for specializing in educational and community facilities. He shares his approach to acoustic design as a well-being issue and presents a case study of the Huntingtower School Performing Arts Centre, an award-winning project that aimed to create an acoustically balanced environment for various musical genres and theatrical performances.

Ben emphasizes that acoustic design is critical in all educational projects, enabling modern learning environments where students and teachers can interact effectively. He explains how poor acoustics (e.g., excessive reverberation) can lead to stress and hinder learning. The Huntingtower project's brief called for a 750-seat semi-professional auditorium with specific acoustic and aesthetic aspirations, including natural music support, an intimate feel, and a large stage capacity.

Ben details the design process, which prioritized the audience experience by shaping the chamber in the round and splitting seats over two levels for closeness. The design fused aesthetic and acoustic decisions, with a timber-lined interior using timber reflectors in the ceiling and timber battens on the walls, acoustically balancing the space. Early consultation with acoustic engineers confirmed the viability of the design's unique shape for managing reflection and reverberation.

Ben highlights the intentional use of curved ceiling elements as hard surfaces to reflect sound to the audience, while timber battens and strategic insulation absorb sound. He explains how acoustic walls in the building, some over 600mm thick, incorporate precast concrete for sound travel reduction and timber battens for absorption, demonstrating a holistic approach to material selection for acoustic performance. The large stage also had specific acoustic considerations.

Ben explains how the curved internal auditorium form is expressed externally, featuring a sweeping northern façade and an arched entrance. The mezzanine area, accessed via a wrapped glass staircase, required careful balance of steepness, view lines, and acoustic treatment (e.g., perforated plasterboard for absorption). The building's tight site constraints and its role as a civic presence for the school also influenced the design.

Ben summarizes key recommendations: consider acoustics in all projects involving human interaction, view it as a well-being issue, fuse aesthetic and acoustic goals, invest time in the briefing phase, address technical resolutions early, and collaborate with acoustic engineers. He emphasizes the critical role of ceilings and designers in translating acoustic concepts to clients, ensuring spaces like the Huntingtower foyer, while lively, are thoughtfully designed.

Ben and Peter answer a question about convincing clients to allocate budget for 'unseen' acoustic elements. They stress that for specialist projects, early engagement with acoustic and theatre consultants is vital to explore options and set appropriate expectations. For general education facilities, Ben emphasizes the direct link between acoustic absorbency and successful learning outcomes, while Peter adds that early planning can influence building layout to reduce overall costs for sound insulation.

Responding to a question about Huntingtower's acoustic function, Ben explains it's designed as a hybrid, strongly supporting natural acoustics but also allowing for amplification, especially in deeper stage areas or for theatrical productions. Peter adds that the balance between natural and amplified sound is dictated by venue size and primary function. Finally, they discuss designing for the hearing impaired, detailing technical solutions like T-switches, infrared systems, and phone integration, emphasizing that good overall acoustic design creates comfortable and inclusive environments for everyone.

Kalani thanks the speakers and attendees, announces the hamper winner, and promotes an upcoming Sculptform webinar on wayfinding case study at Melbourne Airport.