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Acoustics Testing

Audio

Contact

Rob Oldfield
t: +44 (0)161 295 2412
e: R.G.Oldfield@salford.ac.uk

At the University of Salford we have a long track record in audio research and consultancy work, working with companies including… With our extensive, world-class laboratories we offer many different tests and services including bespoke testing and development to fit individual needs.

We are very experienced in running different types of perceptual/listening tests aiming at the assessment of quality in terms of human perception. Using our ITU BS1116 standard listening room we are able to conduct tests in an environment where the room is not a factor in the results. Some examples of listening tests we have performed in the past are the assessment of:

Codecs e.g. Bluetooth/wireless headsets, audio watermarking, compression algorithms etc.

  • Loudspeaker preference tests
  • Amplifiers and audio systems
  • DSP/processing algorithms
  • MUSHRA tests
  • Audio applications for the hearing impaired
audio

Using our expertise in acoustics and audio research into a wide range of subjects, we are able help companies with various aspects of research and development. We recognise that it is not always possible for companies (whether large or small) to commit large amounts of time or human resources to R&D. As a result we have helped many companies in the past to either improve the audio performance of existing products and also to create new products that help give them a new foothold on the market. In the past we have helped, loudspeaker and amplifier manufacturers, fire alarm system designers, algorithm developers and many more improve their business using our research experience.

As part of our extensive acoustic test facilities, we have a loudspeaker robot which is able to make very high resolution loudspeaker directivity measurements in two planes, producing balloon plots of a loudspeaker’s response, we are also able to make many other loudspeaker measurements such as on axis frequency response, group delay, sensitivity etc.

Our experience in audio and loudspeaker design goes back nearly 40 years and whether it is a case of improving and existing loudspeaker design, creating the perfect enclosure for a specific driver or starting from scratch, we are able to employ a range of different modelling and measurement techniques to design loudspeakers that are optimised for a given purpose.

For many years, room acoustics has been the heart-beat of the Acoustics Research Centre at Salford. Many of the absorbers and diffusers that you see on the market currently were partially developed here at Salford and we have substantial expertise in this area. As well as designing individual acoustic treatments we are also experienced in helping people make the best use of their listening/recording or control room spaces, whether it’s designing a room from scratch or retro-fitting some acoustic treatments to make it sound nice.

An in-depth knowledge of audio processing algorithms and digital audio systems enables us to determine many attributes of audio content that are hidden to the average listener. Using bespoke processing algorithms we are able to make expert assessments on audio content to help determine the original source, detect and evidence of tampering and even in some cases, determine the time and place of a recording. Our expertise in this area has led to us being consulted on court cases where an expert witness is needed to assess claims of e.g. audio tampering.

At the heart of modern audio systems is digital signal processing, whether it is an app on your phone, a processing module on a guitar effects pedal or various settings in your hi-fi amplifier, digital signal processing plays a very important part. A large element of work here at Salford is the development and optimisation of DSP routines and algorithms that can enable incredible things to be done with audio.

Ever since the first stereo recording was made by XXX in YYY, there has been a quest for realistic spatial audio recording and reproduction and Salford is no different. We have been involved in research in this area for many years and have written many academic papers in this area. As part of our listening room we have a 114 channel wave field synthesis (WFS) system which constitutes what many people consider to be the stat-of-the-art in terms of spatial audio reproduction. We are also very active in ambisonics and binaural reproduction. Our expertise in these areas has led to us being approached to help develop theme park rides and improve cinema sound as well as spatial audio processing for the television.

Computation models are often used for product development and diagnostics as it is often possible to test a large number of scenarios in a relatively short amount of time. We have experience in numerical modelling techniques such as finite difference time domain (FDTD), finite element (FEM) and boundary element modelling (BEM) as well as analytical modelling solutions and other established techniques such as lumped element modelling and transfer matrix models. Each project is different and the correct model needs to be chosen wisely with a knowledge of its strengths and weaknesses, our breadth of knowledge in this area allows us to work together with clients to choose the correct technique for the given application and write the model such that it generates accurate and powerful results.

For many of the perceptual tests mentioned above, it is first important to assess the hearing abilities of the participants and for this we are able to offer a full audiometric screening which helps greatly with the processing of results and in particular for the assessment on various audio systems for hearing impaired listeners as everyone’s hearing has different characteristics.