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Acoustics of New Adelphi

5 December 2016
New Adelphi Atrium

New Adelphi Atrium

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.

Recording Studios

Studio Control Room

Studio Control Room

Studio Control Room Diffusers

Studio Control Room Diffusers

Recording Studio Live Room

Recording Studio Live Room

Variable Acoustic Absorbers - closed

Variable Acoustic Absorbers – closed

Variable Acoustic Absorbers - open

Variable Acoustic Absorbers – open

Live room HVAC

Live room HVAC

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.

New Adelphi Theatre

 

New Adelphi Theatre

New Adelphi Theatre

New Adelphi Theatre

New Adelphi Theatre

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.

Studio Theatre

Studio Theatre

Studio Theatre

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.

TV Studios

New Adelphi - TV Studio

New Adelphi – TV Studio

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.

Atrium

Acoustic Baffles in Atrium

Acoustic Baffles in Atrium

New Adelphi Atrium

New Adelphi Atrium

Lights in Atrium

Lights in Atrium

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.

Other Spaces Not Photographed

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.

Links to more information

Paper published in the Journal of the Audio Engineering Society, assessment of the quality of distorted audio

7 October 2015

Paper published in the Journal of the Audio Engineering Society by the Good Recording Project team.

http://www.aes.org/e-lib/browse.cfm?elib=17873

For field recordings and user-generated content recorded on phones, tablets, and other mobile devices, poor audio quality arises in part from nonlinear distortions caused by clipping and limiting at pre-amplification stages and by dynamic range control. Based on the Hearing Aid Sound Quality Index (HASQI), a single-ended method to quantify perceived audio quality in the presence of nonlinear distortions has been developed. Validations on music and soundscapes yielded single-ended estimates within ±0.19 of HASQI on a quality range from 0.0 and 1.0. Perceptual tests were carried out to validate the method for music and soundscapes. HASQI has also been shown to predict quality degradations for processes other than nonlinear distortions including additive noise, linear filtering, and spectral changes. By including these other causes of quality degradations, the current model for nonlinear distortion assessment could be expanded.

To go with the publications the authors have also released a program so that if you have some audio that you suspect may be degradaed by amplitude clipping type distortions, this program will be able to detect distorted regions as well as providing a perceptual weighting. Please visit the following link for details on how to acquire the software,

http://usir.salford.ac.uk/35954/

 

 

Salford Acoustics Research and Arup co-host workshop on the use of numerical modelling and auralisation in built environment design

4 September 2015
Arup SoundLab Manchester

The SoundLab at Arup’s Manchester Office

Prof Yiu Lam and Dr Jonathan Hargreaves have been working for the last three years in collaboration with Steve Langdon at the University of Reading and industrial partners Arup and the BBC on an EPSRC funded project developing new computational acoustic algorithms aimed at auralisation applications.  As a culmination of this, they are organising a two day workshop to discuss the latest developments, and future research challenges and priorities, in this field, and specifically its application to built environment design consultation. The workshop will be hosted by Arup at their Manchester office, and will make use of their renowned SoundLab facility for audio demos.

For more information on the programme and speakers see http://hub.salford.ac.uk/acoustics/workshopSept2015/

Dr Jonathan Hargreaves represents Salford at EU research workshop in Freising

4 September 2015

MHiVec project logoMHiVec is an EU FP7 IAPP project which is applying a new modelling method called Dynamic Energy Analysis (DEA) to structural and acoustic modelling of vehicle NVH at mid-to-high frequencies. This method works by transferring distributions of directional wave energy between elements of a discretised mesh of a sub-system boundary, be that an acoustic cavity or a structural element (e.g. a metal plate) and then solving for the steady-state intensities. It therefore has much in common with some late-time acoustic reverberation models and SEA but, like SEA, can be applied to a wider class of vibrating systems.

The MHiVec team organised a workshop in Freising, Germany, at the start of September 2015. Dr Jonathan Hargreaves from the ARC was an invited speaker and gave a talk on synergies between BEM and beam-tracing methods. In return, we are lucky to have MHiVec PI Dr David Chappell from NTU attending and presenting at the computational acoustics and auralisation workshop we are organising in collaboration with Arup on the 22nd and 23rd September, where he will speak on the application of DEA to room acoustics in 3D.

Photos from ICSV 2015

4 August 2015

ICSV 2015 saw lots of hot topics in acoustics being discussed in a very hot environment – it hit over 40°C in the afternoon most days so we were very happy for the conference venue’s nice cool underground theatre and exhibition area. Here are a few photos from the conference.

Dr Jonathan Hargreaves speaking on acoustic cross-energy

Dr Jonathan Hargreaves speaking on acoustic cross-energy

Prof. Yiu Lam chairing his structured session on “Analysis, Perception and Render of 3D Spatial Sound”

Prof. Yiu Lam chairing his structured session on “Analysis, Perception and Render of 3D Spatial Sound”

Sbandieratori demonstrate their flag tossing skills at the conference dinner

Sbandieratori demonstrate their flag tossing skills at the conference dinner

Prof. David Waddington with other presenters from his structured session on "Source, Propagation and Mitigation of Railway Noise and Vibration"

Prof. David Waddington with other presenters from his structured session on “Source, Propagation and Mitigation of Railway Noise and Vibration”

Palazzo degli Affari

Palazzo degli Affari at Firenze Fiera Congress Centre


 

Strong ARC presence at ICSV22

2 July 2015

ICSV_headerThe Acoustics Research Centre will have a strong presence at the International Conference on Sound and Vibration this year with 8 researchers attending to present 8 papers and chair 1 structured session:

  • Dr. Jonathan Hargreaves will present “A high-frequency BEM for 3D acoustic scattering” and “Acoustic cross-energy measures and their applications”.
  • Darius Satongar will present “The acuity of colouration perception using non-individualised dynamic binaural synthesis”
  • Dr. Phil Duncan will present “Audio information extraction from arbitrary sound recordings”
  • Dr. Francis Li will present “Headphone audio rendering – philosophies, challenges and an interim signal processing solution”
  • Prof. David Waddington will present “CARGOVIBES: human response to vibration due to freight rail traffic”
  • Dr. Gennaro Sica will present “Planning ground investigation studies to identify ground-borne sound and vibration parameters for high speed railways”
  • Dr Ian Drumm will present “Workflow automations and optimisations to facilitate room acoustic prediction within multimodal virtual environments”
  • Prof. Yiu Lam will chair a structured session on “Analysis, Perception and Render of 3D Spatial Sound”

JASA Paper on Perception of Room Modes

30 June 2015

Ever since I was doing my PhD I had a sort of quest to measure the thresholds of modal decay for low frequency room modes. During that time, the guys at Genelec Oy were doing a lot of work on digital equalisation of room/loudspeaker responses. They realised that the cost of digital filters would be greatly reduced if the offending modes could be reduced by a given amount rather than total equalisation. I managed to measure modal thresholds but due to the experimental methodology they were defined in terms of Q-factor rather than decay times for specific frequencies. This was later published in the Journal of the Audio Eng. Society in 2007.

Andrew Goldberg, who was with Genelec at that time was also keen to measure the thresholds and, as is often the case in research, was getting similar results to mine but through different routes and methods. We published some papers at the reproduced sound conference and I clearly remember Andrew whispering to me as we went through the typical rigmarole of swapping speakers between presentations: ‘This is all so close!”.

A few years later, Matthew Stephenson started his PhD with me at the University of Huddersfield and one of the first avenues of research we discussed was the measurement of these thresholds. During Matt’s PhD we approached Andrew and set out to finally measure the thresholds.

The work finally got published in the Journal of the Acoustical Society of America this year (March 2015). The thresholds are defined for critical listening modes, i.e. measured with tones and in isolation of masking, and for more general music listening, using music samples auralised within virtual room responses which include effects of temporal and frequency masking. The measured thresholds were then used to define a map which indicates time-frequency regions where modal decay can be detected by listeners.

The thresholds published allow a more precise target for modal control techniques; passive absorption treatment or loudspeaker equalisation filters that attempt to ameliorate the problems of modes in the room. Depending on budget and user requirements, the different thresholds can be chosen. For rooms where audio programme is listened to in a distracted mode (see Truax’s definition of listening modes), the music thresholds can be used to ensure no odd artefacts from the room modes are perceived. For critical listening spaces such as recording, mastering and post-production studios, the thresholds measured with artificial stimuli are more appropriate but will also require more expensive treatment. Finally, for those who want to completely eradicate low frequency room effects from their listening experience, thresholds that lie at the 2.5% confidence interval of the measured data will ensure that no modal effect will ever disturb it.

A link to the publication:

http://usir.salford.ac.uk/34055/

Bruno Fazenda

EASE Loudspeaker Measurements Now Possible at Salford

3 December 2014

We are proud to have invested in a new loudspeaker measurement robot from Four Audio! As well as being able to utilise the fully automated loudspeaker measurement system for many research projects we have now also launched a new loudspeaker measurement service; the first UK based service of its kind.

EASE-Measurements balloon

The ELF system rotates the object under test in both the azimuth and elevation directions, allowing directivity measurements in up to 1 degree resolution in both planes. This provides much more detailed and accurate measurement capabilities than were practically realisable before. The system is primarily designed for the measurement of loudspeaker directivity to be used within EASE modelling packages but also finds many uses for the research projects that we work on and has recently been used for the measurement of the sound emitted by domestic products as part of a research project. For more information you can view our flyer here.

Spatial audio recordings at Abbey Road Studios

3 December 2014

AbbeyRoad-logoSteeped in history yet right up to date, Abbey Road Studios is perhaps the most famous recording studio in the world. From pioneering recording techniques at the beginning of the 20th century through to recording the Beatles in the 1960’s, Abbey Road has always been in the forefront of what’s happening in the audio industry and that has remained the case as last week saw Rob Oldfield perform some cutting edge spatial audio recordings using various object-based recording techniques to enable (amongst other techniques), wave field synthesis reproduction of the recorded scene. Rob over saw the recording of Bob Geldof and the Boomtown Rats and an acoustic set from Lindisfarne as part of one of his commercial work as an audio research consultant. Watch this space for more information on this project at a later date!

 

Experiments in object based audio

1 December 2014

To cope with the volume of information with which our senses are constantly bombarded, our brains utilise a variety of categorisation strategies to reduce the amount of data it has to process. I’m in the process of setting up some exciting experiments in the acoustics labs at Salford to investigate how categorisation is utilised when our brains process complex acoustic information. I’ll be using methods developed in cognitive psychology to determine how listeners categorise individual sounds in different types of broadcast audio material.

The application of this work is in object based audio, which is the future of broadcast audio. Traditionally, audio content is produced in such a way that the channels of audio information are mapped to a specific loudspeaker layout, such as stereo or 5.1 surround. The limitation of this approach is that the experience of the listener is severely impaired if the reproduction loudspeaker layout does not match the layout for which the audio was produced. Object based audio gets around this by sending each individual audio object (this may be a character’s dialogue, Foley effects, or music) along with information about the object’s position in space and time. Using this information at the receiving end, the audio can be reconstructed in a way that is optimal for the reproduction system; be that headphones, a tablet, or a cinema system. This approach also opens up possibilities for the listener at home to interact with the audio content, which had been explored recently by the BBC, such as choosing which side of the crowd you hear in a football match.

The results of the experiments I’m about to run at Salford will help us to understand what types of objects we need to represent when we store and transmit object based audio, and will lead to experiments exploring the effects different objects types have on the quality of the listener’s experience. This work is part of the S3A project, which is a five year collaborative project involving Salford, Surrey, and Southampton Universities, and BBC R&D that aims to develop immersive 3D audio systems that work in real environments, such as people’s living rooms. The project’s just getting started, so watch this space for more information!

Dr James Woodcock