Mr. Yasuhisa Toyota – The honest engineer of Disney Hall

In the distant past, I belonged to an affiliate group of the LA Philharmonic.  This was around the time the Disney Hall project came out of limbo and went into construction.  The highlight of that membership was hearing Mr. Yasuhisa Toyota of Nagata Acoustics speak about concert hall design and the WDCH project, in particular.  My career to that point had been spent in academic R&D, laboratory-scale experimental work, and instrument development. I had little exposure to the practical engineering of large projects under close public scrutiny.

Mr. Toyota’s speech was a revelation and not just for the physics of symphony halls. His presentation to a group of non-specialists was a model of rigor and integrity.  There was none of the glad-handing or gorilla dust that’s often put forth when donors are in the audience looking for guarantees.  Everything he foresaw for the auditorium has come about.

Since then I’ve moved into applied science and actual engineering with customers to satisfy, milestones to meet, and profit to deliver.  That talk, 30 months before the Hall’s Grand Opening, became the standard to which I aspire when I give presentations.   I wrote up my notes from that day and sent them to a few people. I’m reprinting them after the break on the occasion of the Hall’s tenth anniversary.  Please note that the hyperlinks from a long-dated article may no longer work.

The Design of Concert Halls
A talk by Mr. Yasuhisa Toyota
Chief Acoustician of Walt Disney Concert Hall

8 February 2001
(From unofficial notes by Ravi Narasimhan)

[Hyperlinks updated and minor changes made, 29 November 2002]

 

Mr. Yasuhisa Toyota of the renowned Nagata Acoustics group gave a
marvelous presentation today on concert hall acoustics past and present,
especially as they relate to the Disney Hall project finally
underway. Mr. Toyota has been a lead in several important music
projects, especially in Tokyo (Suntory Hall) and in Sapporo.
Herewith some notes from memory on his presentation.

Some halls that are known for their acoustic excellence are in
Amsterdam (Concertgebouw), Vienna (Musikverein), and Boston (Symphony
Hall) and were constructed over 100 years ago. Built in the
now-traditional shoebox configuration, they are narrow but provide a
good listening experience to an audience of up to 1500 people (small
to moderate by modern standards). These halls allow for good direct
sound from players to audience, as well as a first reflection from the
sidewalls that adds to the warmth and richness of the tone. This
configuration held sway for decades and different designs did not
prove as acoustically successful.

The problem facing hall designers is in accomodating more people as
well while not being hidebound to a now-common architectural style
that imposes limitations on configurations. Scaling the shoebox does
not work because as the sidewalls move farther, the reflections take
longer to reach certain groups of seats and so forth. The hall in
Berlin was one of the first to make a major departure from tradition
by moving the stage away from the back wall/proscenium and allowing
the audience to surround the players. This required doing
substantially more than creating an arena-style seating environment
which would have been acoustically poor. The solution was to create
structures within the space that would both hold people but also serve
as acoustic reflectors. Mr. Toyota showed plan/section views of
several halls such as the 1960s vintage Berlin auditorium that were so
built: http://www.ersnet.org/2/1/2_1_3_5.asp
This is the “Vineyard” style of design which
creates some visually dazzling spaces that apparently sound just
dandy, thank you very much. Some advantages of this approach are the
ability to accomodate more people without resorting to excessive use
of balconies or overly lengthening the hall. There are substantially
more seats that get first-reflected sound timed appropriately to blend
with the direct sound. Sightlines are also better. Suntory, Sapporo,
and the Leipzig Gewandhaus are built in this clever manner of
disguising and stacking rounded shoeboxes.
http://www.suntory.co.jp/suntoryhall/english/overview/index.html
http://www.nagata.co.jp/gyoseki/sapporo-e.htm
http://www.gewandhaus.de/psk/gwh/show.php3?id=35&nodeid=35&p=

Designing such a space is substantially more difficult and nowadays a
mixture of computer simulation and scale models are used to examine
how to achieve a given acoustic target within size, cost, seating, and
numerous equally important constraints. We saw plots that showed
direct, first-reflected, and multiply reflected sound fields all over
the new Disney auditorium as a function of time delay. That is, at
any given point, the computer simulations show how much each process
contributes at any specified time after a sound is created on stage.
The codes, I believe, can also account for different choices of
materials used in construction. Scale models are also useful. Light
waves and sound waves reflect and refract depending on their intrinsic
wavelength and the shape and composition of the things off of which
they scatter. Therefore, if one shrinks the size of an auditorium by
a factor of ten so that a model shop can make it, the sounds that they
use to test it must have a corresponsingly shorter wavelength.
i.e. they go to ultrasonic sound generators. We did not have a chance
to explore what this means for experimentally testing the effects of
different construction materials on the result. I am assuming that
this is not a trivial issue.

The architectural layouts were interesting from a couple of
perspectives. First, they showed that optimizing anything in a
project of this size is a daunting task. Secondly, the section views
resemble the beautiful sailing ships of old. While this is claimed
for the Gehry exterior (I don’t see it), the hall has a gracefully
curved keel, two or three decks when viewed in section, and mastlike
features to the ceiling. A non-intuitive statement he made was that
putting people in the seats made only a second-order effect on the
sound. He designs on acoustic considerations, I assume with at least
some defined objectives for sound intensity and reverberation
time that translate to a good audience experience in the end. If he
satisfies those objectives, he has high confidence in the
project’s ultimate success. A further advantage of the Vineyard style
is psychological. Designers think it important that audience members
see not only the performers but also one another in order to get the
feeling that they are participating, if only by their presence, in
something larger and different from listening to music on their
stereos. He hopes that people will recognize one another across the
hall and take the opportunity at intermission or after the concert to
do things together. If it works in LA, it will be a miracle. But, it
is a great idea to try.

Hearing this professional engineer, musician, and music-lover speak
was a treat. The project appears to be in capable and honest hands.
There was no puffery in the man or in his
presentation. He deftly deflected attempts to identify “best seats”
in Disney Hall or in any of the halls he has designed. Regarding the
key issue of seats behind the orchestra, he said that the sound would
be distinctly different but definitely interesting. He pointed out
that when Herbert von Karajan brought the Berlin Philharmonic to
Suntory Hall, the prized seats were behind the orchestra. People
wanted to see him conduct and that gives a much different experience
of the performance. Notwithstanding that the acoustics have to be
good in that area otherwise the horns/chorus would have a bad time of
musicmaking. His pride in having Simon Rattle laud Sapporo as a great
hall was palpable. One questioner asked how much of a contingency
fund would be required to ensure total success in case of unexpected
acoustical problems. The answer, I thought, was a good one: There
are no guarantees no matter how much money is available. He can
exercise his best engineering judgement and bring to bear the lessons
learned from other projects and that is as much as he can promise.
When Suntory opened, orchestra members complained about their ability
to hear certain things on stage. This happened in Berlin as well and
the complaints subsided after a few years. When Mr. Toyota asked the
Berlin hall’s head designer what he had done, the answer was
“Nothing!” The players got used to the different reverberation times
from the ceiling. The exact same thing happened in Suntory Hall.
Given time, the musicians and conductors figured it out.

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