FREQUENTLY ASKED QUESTIONS
What makes a bad
Noise Regulation?
What makes a good Noise Regulation?
How can Noise Regulation be improved?
Can the Grozier system dB results be
fudged?
Do Grozier systems automatically limit
sound levels?
What factors influence the
typical sound level limits?
Why are monitoring microphones
best not located in a community?
How are sound level limits best
established?
Why is music sound bothersome to
some?
Why does music sound carry
further than other sounds?
Can existing community noise
regulations be applied to music sound?
Noise is unwanted sound
What
makes a bad Noise Regulation?
The worst form of noise regulation seems at
first to be the most innocuous. It is one that uses language such as
"annoying sounds are prohibited". It is human nature that there is
always someone somewhere who will find any sound annoying.
Consequently, any activity, under this form of regulation can be
regulated arbitrarily from day to day. This arbitrariness leads to
conflict in a community. For example one faction may claim that a home
coming parade is unacceptable, another, in retaliation, claiming that
pool parties are unacceptable. A good noise regulation permits an
unbiased interpretation that is clear of subjective assessments.
What
makes a good Noise Regulation?
In this web site there are many pages to
help with this, but here is a brief summary.
1. Minimize the amount of sound level data that is needed to verify
conformance. More data often means more capital and operational expense.
2. Put the microphones within the facility and at high sound level
locations.
3. Collect additional data beyond Noise Regulation data so that
diagnostics can be made of any infringement of the regulation. Use this
data in community meetings. Archive this data for future use such as in
preparation for facility expansion.
4. Make sure that factors allow for a proactive opportunity for sound
reduction.
How
can Noise Regulations be improved?
Noise regulations that rely on a subjective
assessment can be improved by quantifying the level of unacceptable
sound. Over 50 years, experts in acoustics have developed a pretty good
correlation between various metrics of sound pressure level and the
annoyance expressed by a majority of reasonable people under various
listening conditions. This experience can be put to good use in the
development of a quantitative noise regulation. The limiting dB level
may depend on the usage to which the land is put. A Grozier system
measures specific sound pressure levels and time signatures, thus
turning subjective opinions of annoyance into quantitative assessments
associated with reasonable people.
Can
the Grozier system dB results be fudged?
Unlike the hand held sound level meter,
which has many controls for the user to adjust, a Grozier system has
none. It is either
ON or OFF. Printed reports are generated as the event proceeds, not
after the fact when electronic editing is conceivable. Local
authorities may even have their own report sent to them live if they
wish. Alternately the sound levels can be reported live to web site.
For the more suspicious, reports can be encoded or a checksum
calculated to determine if a file has be altered.
Do
Grozier systems automatically limit sound levels?
Grozier systems can automatically limit
sound levels but most users prefer to limit sound levels manually.
Management uses the array of sound level data and the predictive
capability of Grozier systems to implement administrative controls.
These administrative controls are applied as a concert proceeds. Sound
engineers from most music groups comply willingly. But if they do not,
this information is stored in the Grozier system for management review.
What factors influence the typical sound level
limits?
Sound level limits should be established at
typical residential locations in the adjacent community. There is three
basic
factors to consider.
1. Those communities with higher noise levels, e.g. industrial zones,
interstate highway zones, typically have higher noise limit levels.
2. Specifying just the dB limit is not enough because the time variant
nature of the community sound has an impact on how annoying the sound
is judged to be. Thus a time-related parameter must be included.
3. The frequency content of the sound may also be important is some
situations. Normally a dBA measure is used in which mid range
frequencies of the sound pressure spectrum are emphasized. However in
special circumstances a dBC measure may be more appropriate in which
lower frequency content is taken into account.
Why are monitoring microphones best not located
in a community?
The sound level limits in a community are
typically established to be lower than the noise from common noise
sources such as motorcycles, lawnmowers, and stereos. Thus a local
microphone picks up sounds that are not from the music venue.
Microphones should be placed closer to the venue where sound levels are
higher and contribution of community noise is lower.
How are sound level limits best established?
Microphones may be located in a position
some distance away from where the noise limit is applied. It this case
a dB relationship between the two locations needs to be established.
This can be done be using a simple measurement procedure. Sound is
played from the venue's loudspeakers and its dB level measured where
the Grozier system microphone are to be installed. Simultaneously, a
sound level meter is used in the community, during quiet moments, to
measure the same sound. The difference between the two readings is
calculated. When the Grozier system runs for a concert, the difference
in dB between the two locations is automatically applied to all Grozier
readings to calculate the community sound levels.
Why
is music sound bothersome to some?
The ear can readily detect the sound of
music even when its dB level is less than the ambient sound. This is
because music carries a beat as well as tonal characteristics. In
addition music carries connotations of cultural forms to which the
listener may be unaccustomed. In addition, if the intrusive music is a
background to another culturally different music, then the listener
will judge the intrusive music to be interfering and annoying.
Why
does music sound carry further than other sounds?
Under some circumstances amphitheater sound
has been detected a long way away from its source. This leads to the
belief that music sound has some physical ability to travel long
distances. However this is just not the case. The sound from, says from
trucks, driving alongside an amphitheater travels just as readily. If
this truck sound were loud enough and had a unique sound signature,
that sound would also be identified at a remote location. However,
because the white noise sound from vehicles carries no musical
information, the sound is judged to be less annoying; the sound blends
into the locally generated white noise, such as wind noise.
Can
existing community noise regulations be applied to music sound?
The most popular form of noise regulation
applies to vehicles and fixed plant equipment (e.g. heat pumps). The
vehicle regulation typically specifies a maximum sound level under
specified operating conditions. The fixed plant equipment regulation
typically applies to steady sounds with or without tones. Neither of
these types of sound could be called qualitatively equivalent to music
sounds. For this reason, noise regulations for music must be developed
separately. But remember music is experienced in many situations. If
you implement a very restrictive music noise regulation, you might find
your own pool party banned. You may even be banned from listening to
the stereo while you wash your car. The Amvets parade or the high
school football game might be fined for excessive noise.
Noise is
unwanted sound?
Lt. Heffernan, during a noise bylaw training class,
once observed very astutely:
When your neighbor cuts his lawn, the sound may be bothersome.
When you cut your own lawn, even though sound is louder, it is quite acceptable.
But when your neighbor comes to cut your lawn, the sound is music in your
ears.
