On Wednesday 16th November we were lucky enough to get a tour of many of the live performance spaces in the University’s new £55m flagship Arts & Media building ‘New Adelphi‘. The tour was given by Salford alumni Matt Robinson, now of Sandy Brown Associates LLP, who was involved in the project as an acoustic consultant. In this role he had to specify the variety of acoustic treatments installed in each space to address both room acoustics and noise ingress and egress, and to liaise with the architect and the construction contractor to ensure that the required performance was achieved.
Our first stop was the basement recording studios. These include a variety of porous and resonant absorbers, to control reverberation time at high-frequencies and modal behavior at low-frequencies respectively, all hidden behind the colored scrim specified by the architect. The back wall features curved devices that offer a mixture of diffusion and absorption at mid-to-high frequencies. The rooms itself is room-in-room construction, to provide high sound isolation performance against noise ingress from the neighbouring live rooms & other control rooms, and from the dance studio above. The live rooms are of a similar construction, with absorptive panels that can opened and closed and mobile acoustic screens to provide variable acoustics. HVAC in both rooms is via a chilled beam system, with the live rooms having an additional forced ventilation system, the intention being that this is used to quickly change the air in the room in-between recording sessions.
The next space we visited was the very impressive New Adelphi Theatre. This is a re-configurable space, capable of working in proscenium-arch or traverse formats. In addition, the rear of the stage has doors that open up to a covered outdoor area (next to Engel’s Beard) to allow for combined outdoor / indoor performances. This is in addition to a large access door leading to the adjacent scenery workshops.
In terms of acoustic treatment, this space had to work for both amplified and un-amplified performances. The solution was to install acoustic diffusers on all the auditorium walls in front of which are heavy drapes. These will give the room a lively but acoustically pleasant character suitable for un-amplified delivery when revealed, or an acoustically dead response when covered, as is usually preferable when working with electroacoustic sound reinforcement. The fronts of the balconies were also designed to be mildly diffusing to avoid strong early reflections.
When introducing this space, Matt talked about how it is often an Acoustic Consultant’s role to suggest common sense solutions e.g. modifying building layout so that areas of noise creation are not adjacent to noise sensitive areas. In this case, other factors meant that the Studio Theatre, which will often be used for dance rehearsal and performance, had to be located directly above the recording studio suite. Structure-bourne noise from footfall therefore had the potential to be a serious problem, so a four-layer isolation scheme was put in place to mitigate this: first there is the vibration-isolated sprung floor; then there is the structural concrete slab; then there is the room-in-room construction of the studios; then there is their suspended acoustic ceiling. To prevent noise ingress / egress through the walls & ceiling, the studio theatre is also room-in-room construction. The inner shell was not capable of carrying the weight of the lighting grid so this is hung from the structural slab above, again with vibration isolators to prevent the possibility of vibration from the flown PA system entering the structure. HVAC requirements in this room were considerable due to the expectation of physically-demanding performances, so a very capable system was specified. This raises the noise floor of the room under intense use, but in those circumstances this is unlikely to be an issue.
This room is tucked away at one extreme of the 2nd floor, so by virtue of this location is relatively well protected from other noise sources. Acoustic treatment therefore was mostly concerned with reverberation control, so that boom microphones can pick up dialog clearly. A track system with heavy drapes was also installed to allow some additional control in this regard. HVAC requirements were quite substantial however as this must cope with the heat created by the studio lighting and is expected to be operated continually during filming.
The Atrium is a large impressive space which would, if left untreated, have had low absorption and a long reverberation time. It was however intended that it be a mixed use space – there are even private study booths installed on the first-floor mezzanine – so reverberation needed to be controlled. Acoustic absorption was added as hung baffles, installed on various ceilings and as a trellis above the study areas. These are particularly effective in such spaces as they offer twice the surface area that the same material would do if installed on a wall, plus the lack of a rigid backing means they are still relatively effective at low frequencies.
Our tour also took in some of the music practice rooms. These feature absorbent ceilings and chilled beam HVAC systems to respectively address room acoustics and eradicate the possibility of cross-talk through ductwork. In addition the percussion practice rooms have absorbent treatment on the walls to reduce the overall SPL by attenuating reflected sound. All rooms look out through the main glass facade of the building, the specification for this is uniform across the building. Since this does not possess sufficient sound insulating properties on its own, and up-speccing it for the entire building would be cost-prohibitive, these rooms have additional glazing to provide increased isolation. The cavity created includes acoustic absorption around its perimeter to prevent reverberant build up.
New Adelphi also has a substantial band practice room, but we were not able to see this on this occasion as it was in use.