Audio Engineering Society Singapore Section

On Friday, 22 October 1999 at 7.00 pm, 9 members and 17 guests of the AES Singapore Section gathered again at the Touch Community Theatre for some light refreshments before a joint seminar presentation by Dr. Roland K. C. Tan and Mr. Christopher K. C. Yap. Both speakers for the evening are members of the AES. Roland was past Chairman of the local chapter between 1996 to 1998 and is also one of the founding members of the AES Singapore Section before holding the post of the Section Advisor since 1998. Christopher was Treasurer in 1997 and since 1998 has been the Section Secretary. 

At about 7.45pm, the seminar started off with a brief introduction by the Chairman, Mr. Jibby Jacob. The first part of the talk was presented by Roland, who first gave an overview of the MultiMedia Theatre (MMT). He shared with the audience on how they got themselves involved in the design of the MMT. They were once colleagues in a newly start-up government funded research centre in one of the local universities, and the idea of the MMT was first brought about because they felt an urgent need for a proper A-V room. This was in order to support the nature of their work, which involved multimedia signal processing. According to Roland, the design of the MMT was part of an overall facility setup that included an Audio/Speech Lab, Video/RF Lab and an NC-25 rated Acoustic Lab. 
 

Although there were clearly other easier options in which they could have taken, such as submitting a tender to engage a professional consultant, it was felt that the recommended solution from a consultant might not be entirely suitable for their area of work in research & development. The A-V components found in most post-production studios or theatres designed for public entertainment have many functions and features that obviously are not necessary in the A-V components for their R&D work. They finally chose to take the challenge of designing a low cost MMT and A-V system integration entirely on their own. They also felt that they could also benefit by learning from the experience gained.
 

Roland stressed that the design must also meet their R&D requirement in digital multimedia signal processing while at the same time not sacrificing high sound quality. This is another important consideration for accurate evaluation, he said. Before he handed the second part of the presentation to Christopher, Roland discussed how they had managed to overcome some of the acoustical problems associated with a small room measuring merely 2.6m by 3.4m by 5.0m. He talked about noise control, room acoustics, sound absorption coefficients, the Sabine formula, reverberation time (RT), resonance and also the Golden Ratio. 
 

In his presentation, Christopher mentioned that unlike a typical home-theatre system set up, the proposed system consists of a mixture of both pro-audio and consumer video components. A Yamaha 02R digital mixer serves as the pre-amplifier in their proposed design, which can provide multiple analogue and digital input and output interface formats. This is unlike a typical consumer home-theatre pre-amplifier unit that has limited number of I/O connections using an integrated multi-channel amplifier. A digital mixer also provides plenty of rooms to include other components that require direct digital connections for future expansion.
 

Active loudspeakers were chosen because it avoided the need of a multi-channel power amplifier, and it eliminates the problem of amplifier-speaker matching. There were also not many multi-channel power amplifiers around in the market in the first place, said Christopher. The models chosen were the Genelec 1031A for the front left, right and centre speakers while a pair of the 1030A was used for the rear speaker setup. The Genelec 1092A sub-woofer was chosen for the LFE (low frequency enhancement) channel. 
 

Christopher then conducted a "guided tour" of the MMT by showing the audience some photographs of the theatre before concluding where he revealed to the audience the total estimated sum of the A-V components alone was merely S$60,000. Indeed, this figure is only a small fraction to pay when compared to the total investment cost needed for facility build-up in any new R&D laboratory. 
 

During the question-and-answer session that followed, many interesting questions were raised. In his reply to a member of the audience, Roland explained that the calculation of the room's RT was based on an empty room. He stressed that if the desired RT can be achieved in an empty room, it should not be a problem when all the furnishings and equipment are included. Another question was raised regarding the placement of the 5.1 multi-channel speaker setup.
 

One member was particularly concerned about possible interference that could introduce undesirable noise distortion. Roland replied that as far as possible they have used balanced mode cables such as the AES/EBU and XLR connections since these are more robust towards noise interference. In addition, due to the size of the small room, he said that the longest interconnection cables that can be found in the MMT were no longer than 10m. It is unlikely that such length could pose any threats from induced noise interference. 

In his reply to a question on how they determined the pre-set volume levels for the digital mixer, Christopher explained that this was not necessary in the nature of their R&D work, unlike for example, in mixer setup for a musical theatre work performance. 

The seminar ended at about 9.30pm. The AES Singapore Section would like to take this opportunity to thank Mr. Robert Soo, Treasurer of the Singapore Section and also the Technical Director of Touch Technical Services, for the use of the auditorium and for the extra manpower support.
 

Biography of Dr. Roland K. C. Tan

Dr. Roland K. C. Tan was born in Singapore in 1964. Upon completing his military service as a battalion signal officer in 1986, he went on to pursue his further studies at the University of Essex (UK) and gained a BEng (1st Class Honours) degree in Electronic Systems Engineering in 1990 and a PhD degree in 1994. His undergraduate final-year project on Waveform Synthesizer for Digital Audio Processor Test Applications was awarded the annual Philips Project Prize in 1990. His postgraduate studies on parametric coding for high-definition digital audio was funded by Meridian Audio (UK) and the ORS (UK) awards under the supervision of Prof. Malcolm O. J. Hawksford at the Audio Research Lab (ARL). He was certified by the Institute of Patent and Trade Mark Attorneys of Australia (IPTA) in 1998 on patent drafting.

Dr. Tan is currently the Senior Manager (Technology Development) under the Technology Services Division at MediaCorp Radio Singapore where his responsibilities include Digital Audio Broadcasting (DAB), Information Technology (IT), and Technology Business Development. Prior to joining MediaCorp Radio in June 2001, he was working with a government-funded R&D institute and has more than 7 years experience in the application of DSP techniques in multimedia applications. He has worked on DSP algorithms that include pitch prediction, time-scale modification, higher-resolution signal analysis, low bit-rate codec, audio test & measurement, as well as multimedia studio design. He has also been actively involved as mentor to the gifted students since 1995.

Dr. Tan is a member of the AES, IEEE, DAB and DTV Committee in Singapore. He is listed in the Marquis Who’sWho in the World 16th to 19th Editions. He has publications in the AES, IOA (UK), IES, Broadcast Asia Journal, Studio Sound (UK) as well as Sound.Works magazines. His article on “Eureka-147 Digital Audio Broadcasting (DAB)” was awarded the 1998 AMIC Award for Excellence in Asian Radio Writing sponsored by the Radio Corporation of Singapore (RCS). 

A founding member of the AES Singapore Section in 1994, he was Secretary in 1994/95 and 95/96, Chairman in 1996/97 and 97/98, and also the Honorary Section Advisor in 1998/99 and 1999/2000. Dr. Tan founded the AES Singapore Section Newsletter in 1996 and was its editor and publisher until 1998. He was Chairman of the organising committee for the AES Singapore Section Seminars that were held in conjunction with PALA’97 and PALA’98. He is currently serving as the Section Web Master since Jan 2000 and has been serving as the Section Student Cousellor since 1998. In Dec 2001, Dr. Tan was elected to serve as a Governor for the AES, Inc. (USA).

Biography of Mr. Christopher K C Yap

Mr. Christopher K. C. Yap received the BEng (Hons) degree from the Nanyang Technological University. He has been involved in the live-sound reinforcement industry since 1989 before joining the Centre for Signal Processing as a Research Engineer in 1996. In 1999, he joined MindMaker, Pte Ltd as a Senior Engineer.

His undergraduate final-year project on the DSP Implementation of Audio Effects later led on to its inclusion in two multimedia PC products, namely the SounDSPhinx developed by Analog Devices Inc., Singapore and the Sensory Station Plus developed by BITwave Pte Ltd. The project involved implementation of modules such as echo, flanging, chorusing, reverberation, spatialisation, and a graphic equalizer.

His R&D interests include audio processing, DSP firmware, psychoacoustics, and live-sound reinforcement. He has also done work on R&D sound studio design and lossless audio compression. He has contributed to articles in the DSP & Multimedia Technology magazine as well as the Broadcast Asia Journal. He is a member of the AES, was Treasurer for the AES Singapore Section from 1997 to 1998 and Secretary from 1998 to 2000.

Copyright 1999 AES Singapore Section