This Month's Meeting Preview

Dale Fawcett, Orchestral Art Inc, and Ted MacDonald, AVM discuss their work on the sound system in the new Molson Amphitheatre

WHAT YOU'LL SEE AND HEAR

Dale Fawcett, Orchestral Arts Inc will present the use of Wolfgang Ahnert's acoustic design program E.A.S.E, Electro Acoustic Simulator for Engineers, in the design of the signal delayed EAW KF850 loudspeaker array for the 7,000 lawn seats at the new Molson Amphitheatre.

Ted MacDonald, AVM, will present a walkthrough of the Amphitheatre, and discuss the installation process and the constraints AVM worked under, including a very tight deadline.

WHO THE PRESENTERS ARE

Dale Fawcett, studied music and acoustics at the University of Toronto, graduating in 1976. While a student, he worked as a studio musician with some of Toronto's finest jazz artists. In 1977, at the invitation of the choral conductor Sir David Willcocks, he began a two-year scholarship at the Royal College of Music in London.

Since 1982, he has devoted his abilities to the field of acoustics. He is the principal of Orchestral Arts Inc, a firm specializing in room acoustics and audio system desgin. In 1987, he was one of the first professional audio users of the TEF acoustic analyzer in Canada. Dale has acted as music director for The Canadian Brass and musical advisor on three of their CBS Masterworks recording.

Projects have taken Dale to the Abbey Road Studios in London, and Paramount Pictures in the United States. He is particularly interested in the acoustic and electro-acoustic of larger venues, and has just completed a centre cluster design for the National Arts Centre's 2600-seat Opera in Ottawa.

Ted MacDonald, AVM, has worked in the music industry for over 23 years. He was headtech for RUSH for several years during their early touring days, and was road manager for Kim Mitchell.

He was the second employee to be hired by Westbury back in the early '70s before starting out on his own with Audio Video Methods, or AVM Group as it is now known. AVM has installed the sound and lighting systems in most of Toronto's major clubs, and is now venturing into larger performance sytems, including the Molson Amphitheatre. Currently, AVM is working on the centre cluster sound system for the Toronto NBA Raptors at the Skydome, using Community speaker boxes, and Crest amplifiers.

WHERE TO GO

Park in front of the Molson Amphitheatre at Ontario Place (you can't miss it), cross over the bridge and go to the loading dock area, and enter at the glass doors. Signs will point you in the right direction.

What's Inside

Editorial

Welcome to the first issue of the 1995/96 volume of the Toronto AES Bulletin.

I am looking forward to another event filled year of working with the enthusiastic and committed AES members of our Executive. My last five years working on this committee (I now have the honour of being the sole remaining member of the original Muncy Group) have been enriching and stimulating, to say the least. Left on my own, I would probably concentrate on my particular love in audio - music production - and not pay too much attention to the many other related and supporting disciplines.

Instead, I have seen the technical marvels of the bare shell of one of the world's finest production facilities (CBC), and then seen it in its finished state; I've toured virtually any production, performance or manufacturing facility of note in the Toronto area, talked with, made friends with and learned from the people who manage, invent, create, slug it out, innovate, and push the state-of-the-art in these facilities.

I've met many of the world's most respected audio professionals... people who I otherwise would only know through their published works... and have been infected by their drive and enthusiasm to excel in their own fields.

Every bit of effort I have put into the AES has been richly rewarded, and looking at our plans for this year, I know that there is more to come! We publish a monthly Bulletin, have a presence on the Internet and on Horizons, a Toronto area BBS that will soon be accessable via the Internet.

We are again offering a blend of technical and practical meetings that will hopefully appeal to the diversity of our membership. And we are as always expanding our goals, and hope to attract more new members to the Toronto section.

All that we require from you is your continuing support and constructive feedback... and to pass along word of what we are doing to your friends who may benefit from what we do!

What's Inside

Last Month's Meeting Review

Dolby AC-3 and Annual Social Meeting Review

The Toronto Section of the Audio Engineering Society (AES) closed off another successful year with the annual social held this year at Sony Music Canada on Tuesday, June 14th.

Set in the very nice Sony Music Canada multimedia theater, our multipurpose meeting was off to a good start with Louis Fielder, AES President and manager of Dolby Labs' bitrate engineering group.

He explained the origins of the AC-3 coding, from 1982 experiments, via the AC-1 and movie theater AC-2 systems, and the advent of low cost DSP. Similar to other such systems, it uses 25 frequency bands per channel, of one-fifth octave, except at the low end. Masking effects in these bands are exploited fully, as well as outside: at 100 dB SPL a 100 Hz sound masks up to 4.5 Khz; at 20 dB lower, to 1 KHz.

Low pitch sounds are not masked well by higher ones, so 90dB/octave filter rolloffs apply. Analysis is phase-linear and DSP/FFT based with 512 points. Constant-frequency sounds are sampled at fractions of the max. rate, and activities on all 5.1 channels are differentially monitored for possible data rate swapping. To avoid dynamic artifacts, all channels are cross-correlated at a 5 mSec rate.

The main difficulties were in achieving the steep filter rolloffs, and dual slope masking dynamics, in low cost hardware. Since better cost/performance will come, the bit allocation process is reprogrammable in software.

The car sound and home theater markets need a modest compander function (90 dB into 60) to keep the level up, but not too loud during commercials. Companding centers on -23 dB. Only the "lunatic fringe hi-fi enthusiasts" want the full range, and therefore can manually select that mode. In the AC-3 data frames there are copy protect bits, codes for the many channel mode combinations (from mono to full 5.1 channels), and to code the data rate within its 32-640 Kbit/second limits. A multilingual/comment channel mode is coming. Typical bitrates are 320-384 Kb for 5.1 ch, 112-256 Kb for surround stereo, 56- 128 Kb for mono, and down to 32 Kb for speech.

Uses include HDTV, theater, Primestar in 1998, DMX radio, video disk, etc. Examples of rock, pop, and classical stereo music at 20 KHz bandwidth were played in original/coded/difference modes, at 192, 128 and 96 Kbit rates. There was some sibilance loss at the lower rates, but the reproduction was still excellent. The difference mode made a dandy new sound effect.

After a Q& A session, Earl McCluskie announced the new Executive, and the probable shift of our meetings to the fourth Tuesday in the month, to be able to use the Ryerson/Rogers/Eaton Lecture Theater, a permanent and very nice venue! Then we enjoyed the food and beverages provided by the AES, our year-end social, and guided tours to the cassette and CD production areas of the Sony plant.

In Toronto, John Fourdraine

What's Inside

What's New

LiveWire Remote Recorders, with AES Toronto's very own Doug McClement, has been busy this summer. From a Much Music special this fall featuring the two sold out nights with Van Halen at this month's meeting venue, the Molson Amphitheatre, to the Skydome and Billy Graham and a 45 piece orchestra, 5,000 voice choir, two gospel/rock band setups, and innumerable RF mikes, a TV special in Montreal starring Holly Cole, and Diane Bish, classical organist (you've seen her on Vision TV).

Neil Muncy and Associates are consulting for the Toronto International Film Festival at the Roy Thompson Hall. Neil aligned the awe-inspiring surround sound system... the ultimate theatre venue!

Coming next month, thanks to Doug McClements, the Bulletin will be publishing the definitive guide to Toronto's multitrack facilities.

Horizons has moved!! The new phone number is 416-480-0181. This will allow more members access to the system without incurring a long distance charge. Other happenings on Horizons: In order to make the board more useful as a resource to professionals dealing with the technical aspects of the arts, select internet news groups are now available. These include: comp.cad.autocad comp.cad.pro-engineer rec.arts.movies.production rec.arts.theatre.stagecraft rec.audio.pro; sci.electronics.repair plus many more (more are added as they are requested.)

If you have any questions please contact: Glenn Specht or Peter Cook

What's Inside

1995

Articles may be used with the Author's Permission. Contact the Bulletin Editor: earlm@opentext.com

Editor: Earl McCluskie Layout Editor: Lee White

The Bulletin is prepared in print by Lee White, and on Horizon and the Internet by Earl McCluskie.