By Mike Boehm, July 1, 2014
Architect Frank Gehry was among those concerned that the planned subway trains would affect Disney Hall's acoustics.
The builders of a subway that will run between Walt Disney Concert Hall
and the Colburn School of Music are promising to deploy a triple helping
of the most advanced noise-suppression measures to make sure the rumble
of light-rail trains under 2nd Street won’t mar audiences’ musical
experience or intrude on the sound quality of recordings made in the
An agreement between Disney Hall’s landlord, the Music Center, and
the Los Angeles County Metropolitan Transportation Authority went into
effect this week, formally committing Metro to making sure that the
sensitive stretch of its $1 billion downtown Regional Connector Project
won’t add any audible vibrations.
The agreement sets out a process
for what will happen if those preventive measures fail -- with a Music
Center lawsuit to collect damages the worst-case scenario.
Metro and Music Center officials say they’re confident that the
precautions being taken will allow subways to run silent and run deep
(135 feet below street level) in a way that won’t impinge upon Disney
Hall’s acclaimed acoustics.
The danger is not from the typical screeches and loud rumbling noises
that passengers waiting on a subway platform are accustomed to hearing.
The subway, expected to begin running in 2020, is too deep for those to
register in the concert venues.
The threat is vibrations created
when metal train wheels pass over metal tracks. Strong vibrations could
send energy waves through the ground and into the concert venues,
emerging as a low-frequency rumble in the halls. So the key is to stifle
vibrations at the source.
Bryan Pennington, Metro’s chief of engineering and construction, said
that contractors building the subway won’t use any new technologies to
accomplish that, but the transportation agency will make sure that three
proven noise-reduction techniques will be pushed to their “ultimate
He said that two of the main lines of defense are
rubber padding beneath the railroad beds that support the subway tracks,
and rubber insulation installed in metal fasteners that connect tracks
to the railroad bed. Pennington said that typically one or the other is
deployed to prevent noise problems. Metro will install both in the
tracks running past Disney Hall and the Colburn School.
Pennington said that Metro’s engineering and construction contractors
will be asked to find the optimal kind of rubber to use in the noise
abatement padding and insulation.
Additionally, he said, the
concrete slabs into which tracks are laid will be stiffened as much as
possible – another way of making sure vibrations from the tracks won’t
The agreement comes after more than a year of talks
between Metro and the Music Center that ensued after a subway simulation
test at the Colburn School yielded audible low-frequency noise,
alarming, among others, Disney Hall’s architect, Frank Gehry, and its
acoustician, Yasuhisa Toyota.
Metro and Music Center officials said that ensuing talks culminated
in tests aimed at establishing the amount of “ambient noise” that’s
detectible in Disney Hall when it’s empty and quiet – a level that Metro
is now committed to keeping intact even with subways running by every
Howard Sherman, the Music Center’s chief operating
officer, said that all of Disney Hall’s tenants, including the Los
Angeles Philharmonic, the Los Angeles Master Chorale and the REDCAT
theater, were involved in the noise discussions over the past year.
said the cooperation from Metro has been consistently good, with all
parties sharing the aim of an inviolate concert and recording
Pennington said the noise abatement measures and
specifications have been codified in Metro’s contracts with its subway
designers and builders, the U.S. division of Sweden-based Skanska and
Traylor Bros, based in Evansville, Ind., which are both construction
companies, and Hatch Mott MacDonald (HMM), engineering and design
He said he had no estimate on how much those measures might add to the cost.
Sherman said it has been clear that Metro’s aim isn’t to minimize expenses but to ensure optimal sound in Disney Hall.