British Section Meetings
2008-2009 Programme
Upcoming Events
Tuesday 9th June 2009, 7pm
Lecture: How to make a high-resolution record label
Philip Hobbs, Linn Records
Venue: RAE, London
Tuesday 14th July 2009, 7pm
Lecture: Grand Designs - Networked DSP for Really Big Buildings
Michael Page, Peavey Digital Research
Venue: RAE, London
Lectures
Please note the new lecture venue
Lectures are free and are open to all - members and non-members. Lectures are normally held at the Royal Academy of Engineering (RAE), 3 Carlton House Terrace, London. SW1Y 5DG. It is just off Waterloo Place between Pall Mall and The Mall. It is a five minute walk to Piccadilly Circus Underground Station and ten minutes to Charing Cross mainline and underground stations, or 20 minutes through St James's Park to Victoria.
Refreshments are available from 6.30pm and the lecture starts at 7pm.
Technical visits
Technical Visits are available for members only. You must book in advance as numbers are limited. Further details of where and when to meet will be sent out with your booking confirmation.
Event details
Tuesday 14th October 2008, 7pm
Lecture: Surround Sound Audio Codecs in Broadcasting - an Introduction and Latest Results from Independent Listening Tests
by David Marston
Tuesday 11th November 2008, 7pm
Lecture: The Engineering Art Behind the Beolab 5 Loudspeaker
Gert Munch
During this lecture Gert Munch will demonstrate how the development of several key technologies, including the development of "acoustical lenses," led to the design and implementation of the BeoLab 5 loudspeakers. He will explain the main technical challenges faced during the development process and will show how they have been solved. In particular, he will discuss the issue of the directivity control, a challenge of obtaining the required acoustic power using the designed loudspeaker enclosure, and the challenge of the room acoustics adaptation. Moreover, he will discuss the issue of production of loudspeakers that should act the same regardless of the time they are produced ("cloning" in production). The talk will be illustrated by specific examples of measurements obtained using the BeoLab 5 loudspeakers and their "predecessors".
Friday 28th November 2008, 11.30am for noon
Technical Visit: British Library Sound Archive Technical
Venue: British Library Centre for Conservation, London
Nigel Bewley is the Operations Manager for the British Library Sound Archives, Technical Services and he will present Detection and Deception, an informal talk, with audio illustrations. During, and after, the presentation, he will answer questions about the work of the Sound Archive and there will then be an opportunity for a visit to the technical facilities in Technical Services. The studios were completed in March 2007 and comprise ten transfer studios, a recording studio, workshop and lab.
This visit will start at 11.30am and it is anticipated that it will finish around 1:30pm. Members are welcome to stay on afterwards to enjoy the public areas, including the exhibition galleries. Places are limited and need to be booked, so please contact Heather as soon as possible on 01628 663725, or email uk@aes.org.
Tuesday 9th December 2008, 7pm
Christmas Lecture: An Interview with Bob Stuart of Meridian Audio
conducted by Keith Howard
Bob Stuart has been a major figure in the British audio industry for over 30 years. Best known as Chairman and co-founder, with Allen Boothroyd, of what is today Meridian Audio Ltd, he has done much more than steer the company through challenging times to its current high-profile position manufacturing some of the most sophisticated audio equipment available. A pioneer of active and then DSP-equipped loudspeakers, he was quick to recognise the potential of CD and, as part of the ARA, to push for a version of DVD dedicated to high-resolution multichannel audio. Meridian's own lossless compression algorithm, MLP, was developed in anticipation of this and selected by the DVD Forum for DVD-Audio in a technology shoot-out against stern competition. In expanded form it remains the basis of the Dolby TrueHD lossless compression scheme used in Blu-ray Disc. With a long-standing interest in psychoacoustics, which he studied alongside electronic engineering at Imperial College, Bob is one of very few creators of high-quality audio equipment to have studied the fundamentals of sound perception and generated computer models of human hearing to help guide the design process. In recent years, in collaboration with Peter Craven, he has investigated the effects of digital anti-aliasing and reconstruction filters, one intriguing result being that Meridian's latest flagship CD player - the 808.2 Signature Reference - uses minimum-phase rather than linear-phase output filtering.
These subjects and many others will be covered in this interview, with Bob presenting supporting material to clarify the issues.
Tuesday 13th January 2009, 7pm
Lecture: Loudness
Thomas Lund
Sample based level restriction may have been adequate in the early days of digital audio, but dynamics processors now exploit our archaic measurement principle to an extent where significant distortion develop downstream of the studio in perceptual codecs, DA and Sample Rate converters.
The lecture shows how production methods in combination with simplistic level assessment is responsible not only for more distortion, but also for level jumps where digital interfacing or file transferring is used, e.g. in digital television.
Recent research in the field of loudness measurement of time varying sounds is discussed, and various ways of extracting programme-duration audio descriptors from such measurements are presented. It is shown how a closed loop from production and mastering to transmission, distribution and logging may transparently cover multiple genres, formats and platforms.
The lecture has a scientific angle and does not endorse commercially available equipment. It is targeted to audio production, mastering, transmission and management professionals in music, broadcast and film.
Tuesday 10th February 2009, 7pm
Lecture: QESTRAL: Quality Evaluation of Spatial Transmission and Reproduction using an Artificial Listener
Francis Rumsey
Institute of Sound Recording, University of Surrey
Most current perceptual models for audio quality have so far tended to concentrate on the audibility of distortions and noises that mainly affect the timbre of reproduced sound. The QESTRAL model, however, is specifically designed to take account of distortions in the spatial domain such as changes in source location, width and envelopment. It is not aimed only at codec quality evaluation but at a wider range of spatial distortions that can arise in audio processing and reproduction systems, such as downmixes and changes in the reproduction layout. The model has been calibrated against a large database of listening tests designed to evaluate typical audio processes, comparing spatially degraded multichannel audio material against a reference. Using a range of relevant metrics and a sophisticated multivariate regression model, results are obtained that closely match those obtained in listening tests.
Thursday 26th February 2009, 2pm
Technical Visit: Science Museum Audio Archive
Venue: Science Museum, London
Places are limited and need to be booked, so please contact Heather as soon as possible on 01628 663725, or email uk@aes.org.
Tuesday 10th March 2009, 7pm
Lecture: Can One Perform Quasi-anechoic Loudspeaker Measurements in Normal Rooms?
John Vanderkooy
University of Waterloo, Canada and B&W Loudspeakers
This talk is an analysis and practical study of two methods that attempt to achieve high resolution frequency responses at low frequencies from measurements made in normal rooms. Such data is contaminated by reflections before the low-frequency impulse response response of the system has fully decayed. By modifying the responses to decay more rapidly, then windowing a reflection-free portion, and finally recovering the full response by deconvolution, these quasi-anechoic methods purport to thwart the usual reciprocal uncertainty relationship between measurement duration and frequency resolution. One newer method from Juha Backman works by equalizing the response down to dc, the other older one from Laurie Fincham by increasing the effective highpass corner frequency of the system. Each method is studied with simulations and some real measurements, and both appear to work to varying degrees. In some sense these methods are effectively simple model extensions. In practice noise significantly degrades both procedures.
Diffraction of a loudspeaker cabinet is important at low frequencies. Some aspects of diffraction will be discussed which may help to understand some of the response trends below 300 Hz.
Tuesday 14th April 2009, 7pm
Lecture: Surround sound audio codecs in broadcasting - an introduction and latest results from independent listening tests
David Marston
Surround sound systems are now becoming a popular addition to many people's homes. This means there is now a demand for surround sound content to be delivered to homes via broadcasting, internet or recorded media. Whichever way it gets to it's destination, it is going to require data reduction along it's journey. This may be in transmission end of a broadcast chain, or in the transport of audio from a studio out over a broadcaster's network.
This data reduction uses audio coders designed for surround sound. There are currently numerous different audio coders available, often with different attributes and performance. Choosing which coder to use is not a simple choice, and one of the key factors in this choice is the sound quality. It is inevietable that for serious data reduction, the coder will have to be lossy and therefore compromise sound quality. Our work assessed the sound quality of a selection of audio coders using the most accurate instrument of measurement available: the human ear. Here we present the codecs tested, how the tests were done, and of course the results.
Tuesday 12th May 2009, 7pm
Lecture: Reality is Not a Recording / A Recording is Not Reality"
Jim Anderson
The former New York Times film critic Vincent Canby wrote: "all of us have different thresholds at which we suspend disbelief, and then gladly follow fictions to conclusions that we find logical." Any recording is a 'fiction', a falsity, even in its most pure form. It is the responsibility, if not the duty, of the recording engineer, and producer, to create a universe so compelling and transparent that the listener isn't aware of any manipulation. Using basic recording techniques, and standard manipulation of audio, a recording is made, giving the listener an experience that is not merely logical but better than reality. How does this occur? What techniques can be applied? How does an engineer create a convincing loudspeaker illusion that a listener will perceive as a plausible reality? Recordings will be played.
Wednesday 3rd June 2009, 7pm
Lecture: Critical listening/evaluation - a path to the future of quality music
George Massenburg
Tuesday 9th June 2009, 7pm
Lecture: How to make a high-resolution record label
Philip Hobbs
>In 2007 Linn Records pioneered the selling of DRM-free, high-resolution music downloads - a delivery model that many others in the record industry are now beginning to adopt. In this lecture Linn Records' chief classical producer/engineer Philip Hobbs - whose recording of the Mozart symphonies 38-41 with Sir Charles Mackerras and the SCO won the Critics' Award at the recent 2009 Classical BRIT Awards - will describe how the download service was introduced, how it has operated and how the range of different download options has expanded, most recently to include 192/24 files. He will also explain the operation of Linn's DS streaming network audio players and play some examples of recent recording projects at different resolutions.
Tuesday 14th July 2009, 7pm
Lecture: Grand Designs - Networked DSP for Really Big Buildings
Michael Page
Advances in audio distribution and control over digital networks have delivered tremendous benefits for operators of large venues and premises, such as theme parks, cruise ships, stadiums, live performance venues, airports and industrial complexes. Audio for entertainment attractions, background music, paging systems and evacuation purposes may all be transported and controlled on a single distributed system, via Ethernet and IP local area networks. Audio processing for acoustic correction, routing, mixing and other processes is all easily performed using programmable DSP, located both centrally and at distributed nodes. Michael Page of Peavey Digital Research will discuss and demonstrate the technology used to achieve this.