I have been practicing acoustical, audio and sound engineering for more than twenty years. Since I understand many aspects of sound, I sent the enclosed letter to the Chattanooga City Council members regarding some of my concerns on the impending noise ordinance changes. My comments were unacknowledged.
August 19, 2014
Dear Chattanooga City Council Member,
This letter is in regards to the anticipated noise ordinance changes. I addressed the council on July 29 hoping to establish that much work must be done before enacting any legislation. It is clear that no one with any real knowledge of acoustics is involved in writing this ordinance. For starters, the use of the term "sound" for renaming the ordinance, in lieu of the original term "noise", is disingenuous. It may be an attempt to change the connotation from negative to positive; and it may be viewed as a matter of semantics. However, noise has a distinct definition and exists as a subset of sound. Given the body of the proposed ordinance, noise is the correct term.
Acoustics is a bona fide scientific field, where engineers and physicists spend entire lifetimes in its pursuit. If the theory were easy, then there would be no need to study it. Instead, it is an advanced degree concept. So, it is particularly funny when lay people and especially lawyers become sudden experts in it. I have never heard such misuse of acoustical terms and practice by the general public, as I have in the last three weeks. Likewise, those who penned the ordinance changes are demonstrating their ignorance. While code writers are free to define generic definitions, they should never corrupt long-standing national and international standards terminology. The proposed ordinance language does just that.
Every city with an entertainment district that I investigated has special caveats associated with the permissible sound levels for protecting the residents. The Fort Lauderdale, Orlando and Fort Myers Beach districts have distance specifications, with the latter having an additional residential zone sound level restriction. New York City requires bars and restaurants to limit their music to 42dB(A) as measured inside the nearby residences. Austin's district exists in a relatively small area, which is buffered entirely by a central business district. And, the Nashville district is surrounded mostly by specified buffer zones, with the exception of two residential zones that are separated by I-40. Nashville includes a distance requirement; and venue loudspeakers must be aimed away from doors. Furthermore, it has a very lengthy building code and an ordinance clause to protect against "…loud noise sufficient to constitute a breach of the peace". As currently written, the Chattanooga Downtown Amplified Music District (AMD) will stand alone in having no requirements to protect other businesses and residences.
Not only is 80dB(A)/90dB(C) extremely liberal, but the fact that it is defined at the property line is unbelievable. Sound levels require a locating point and are derived from a source's power. Sound power is a measure by which all sources can be compared. For those businesses abutting a street, the property line would be at the door, say five feet. But, some properties in Chattanooga have extremely large lots, say 150 feet. The power of the 150-foot source can be about 30dB greater than the one at five feet. While both emit 80dB(A) at the property line, the larger source carries over a significantly greater distance. In the absence of an obstruction, one would have to be about 85 feet from the smaller source's property line and almost ½ mile from the larger source's property line before the sound levels are lowered to 55dB(A). Also, as an additional point of reference, 30dB represents a power that is 1,000 times greater. A human perceives that difference as eight times louder.
The recently added statement that the sound levels will be "averaged" for the AMD is also an issue. The aforementioned entertainment districts do not include an averaging statement; rather, they establish their sound levels based on maximums. In terms of music, impulsive or short duration hits, like percussion strikes or random screaming, must be under that cap. With averaging included, Chattanooga will allow certain violations of the permissible sound levels, where the other cities do not. It amounts to a doubling of the sound levels based on a halving of the pulse time. An excellent example of this is a kick drum. Moreover, by using the average, songs could be allowed to end with a bang, literally.
The language used for the sound level meter is meaningless given the details within the ordinance. It is correct to say that it is as an ANSI meter, and the slow response is appropriate for the city-wide sound levels. But, there is omission of type, methods of measurement, and an incomplete interpretation of integration based on the new AMD requirement of one minute averaging, which further demonstrates a complete misunderstanding on the part of the author. Moreover, a $200-$500 meter satisfies the non-AMD requirement, while a $1,000-$3,000 meter will be needed for AMD monitoring. Did anyone check with the police department to find out what they are carrying, and who will supply any new meters as necessary? Unless there is clear and constant violation, I see a need for the operation of data recorders with audio recording capability at the property lines of AMD permitted businesses in order to substantiate the violations of an intermittent source like music. A data recorder will also capture the background as required.
Regarding the enforcement and penalties section, it is well known and recognized by all that the financial penalties amount to the cost of doing business for those using amplified sound and serving alcohol. The only substance being put into this new law, is a simple threat of the alcohol licenses being revoked by another party. The language says, "…violators…will be referred to the appropriate city regulatory board. The board may assess additional penalties, including, but not limited to, suspension or revocation of permits…" So, basically the city is going to cross its fingers that something more may (or may not) happen; and permit suspension and revocation becomes political. Real "teeth" in the law amounts to the additional inclusion of criminal penalties.
Regarding the AMD permit process, the ordinance language places the burden in determining whether a permit should be granted on a Land Development Officer. It is being based on a business's inability to feasibly meet the city-wide sound level requirements. This includes ensuring that sound mitigation actions "…have been taken to comply with the noise level limits…including, but limited to, building design, landscaping, and buffering..." My concern is that no engineer in that office will understand the principles of acoustics sufficiently, as it is an extreme specialization. Noise control is very detailed and very costly. Say it is determined that the applicant must pay $250,000 to meet the city-wide permissible sound level. He or she will seek an AMD permit in lieu of paying that expense. Say the Land Development Officer agrees that $250,000 is too much for an applicant to pay and grants the permit. Now, each receiving property owner will have to pay to fix his or her individual building structure, which creates the potential for a higher, overall price than the original $250,000. The Land Development Office must be truly committed to study the shifted acoustical costs to receiving properties before each and every AMD permit is granted. There is too much at stake for the receiving property owners. Furthermore, the Land Development Office should be prepared to establish new building codes for any future businesses and residences moving in and around AMD permitted businesses.
Regarding the AMD Board of Appeals, there is no language on their selection basis except by location. They should be vetted to prove that they have some knowledge of acoustics. I have included a list of terms that they should be familiar with before being selected. If they aren't, then they won't be able to appropriately judge a situation or serve effectively. The list of terms supplied is not intended to overwhelm, as they represent only the basics.
Regarding the boundaries on Broad and Market Streets, the owners of the excluded businesses that utilize amplified sound and serve alcohol should be concerned about their futures. I have seen many times where formal opposition is organized and backed by the actual competition disguised as "shell" interest groups. In time, these facilities could be closed by competitors and/or residents through sound monitoring. According to the current language, the non-AMD permitted businesses are going to be subject to the same scrutiny as AMD permitted businesses, when it comes to the alcohol boards. In the spirit of fairness to long-existing facilities on Broad and Market, the boundaries should be reconsidered. Furthermore, there is no guarantee of any future additions to the AMD.
Regarding the current opposition to the proposed AMD, the contingent is seemingly being dismissed by most, based on their small number. The only outraged parties appear to be a few homeowners on the south side. Meanwhile, the entire process over the last three weeks has largely gone unnoticed by the general pubic, including many others who are going to reside and work in and around the AMD. The reason for the large discrepancy is very simple. Over the last couple of years, that small contingent has existed in the shadow of what is to come for everyone else living and working in and around the AMD. Most, who will be impacted, are simply oblivious right now, because it hasn’t happened in their "backyard" yet. But, once the process begins, the outcry should increase exponentially with each AMD permit granted. When residents can't achieve regular sleep and daytime businesses are interrupted by sound checks, it will be too late for a reasonable solution to be implemented.
A city would not normally need to retain an acoustician for consult on noise ordinances. However, given the scope of the changes that are about to impact Chattanooga regarding the AMD and the poor authorship of the proposed ordinance, it is appropriate. The wording of the definitions alone reinforces to me that the code writer has no concept of what A- and C- weights really mean in terms of the human impact. And, it is here that a stream of questions can be raised to the city engineers, city lawyers and city council regarding the human factor.
1) Where is the formal response to the specified task in the "The Economic Impact of the Music Sector in the Chattanooga, TN Region" document, where "…the City of Chattanooga will need to bring together a diverse set of stakeholders including residents, businesses, and music sector stakeholders to determine the appropriate boundary and related public policy on issues such as noise levels, safety, street closures, and zoning…"?
2) Why hasn't a thorough review of other cities with entertainment districts been performed, including a complete analysis of permissible sound levels coupled with non-property line distances, buffering zones, mandatory building codes, etc.?
3) Why doesn’t the AMD permit applicant have to submit a site plan…", which shows the general plan for utilization of any building (including…decks, balconies, covered areas and patios), distances from nearby residential zones, locations of any amplified speakers in the building…and any proposed landscaping or noise reduction efforts which will be taken to protect nearby properties from excessive noise…", as is currently required for those seeking a late night entertainment special use permit per Sec. 38-527(2)?
4) Has a proper Noise Impact Review been prepared and published?
5) Why hasn't a sound survey, which serves as a baseline for comparison in and around the proposed AMD, been performed?
6) What are the measurements of success or nonsuccess to be evaluated at the one year review? Will the ordinance be repealed at that time, if the results are not favorable?
7) Who will create and maintain the noise impact map with additive sound level overlays in and around the AMD?
8) Where is a formal report stating that the noise levels emitted from the AMD into the existing residential districts will not be a detriment to their peace, health and/or psychology?
9) Has anyone performed the ISO standard calculation for determining the community response level to the AMD in an urban environment?
10) Has anyone performed a noise calculation to evaluate the need for new speed limits, speed bumps, stop signs, or road closures?
I will help with this last item. With the speed limit set a 30mph in the downtown, the average passenger vehicle will produce 80dB(A) at less than 7 feet. Assume some guy, with his eyes on a smart phone, crosses a street in the AMD in front of on-coming traffic. At the permissible sound levels, he will have a 0.15s aural warning before being struck. Verbal shouts from by-standers may also go unheard, so safety is now an issue. Pedestrians will be injured or killed. In the absence of a proper study, would the city have some culpability?
I support an entertainment district in Chattanooga, but the proposed numbers coupled with proposed boundaries must be given proper consideration. This is not a simple everyday issue before the city council. It can have devastating effects, if not implemented properly. It is a full blown engineering problem, touching more than the acoustical field. It is my opinion that reports, studies and calculations must be commissioned before this proposed ordinance is passed to prevent the city from falling down the rabbit hole of lawsuits with no defense. I believe the city must make an informed and respectful decision based on facts. When the City of Chattanooga does retain an acoustician, his or her credentials will be challenged by me. Any report must be stamped by a professional engineer, because that report will state where certain sound levels are acceptable, along with the conditions that must be met for proper protection of all including homeowners and the general public.
P.S. The A- and C- weighted sound levels are both based on human hearing. The proposed ordinance language indicates that only the A- has such a distinction. A- is the weight assigned to low sound pressure levels (40dB). B- is the weight assigned to medium sound pressure levels (70dB) C- is the weight assigned to high sound pressure levels (100dB). The curves are based on equal loudness contours developed in the 1930's. A person's low frequency hearing becomes more acute as the volume increases. So, when someone is subject to 90dB(C), he or she is hearing almost 90dB; and A- is a misapplied measure at that sound level. It is perfectly fine to use the A- and C- settings of a less expensive sound level meter as a "poor man's" representation for an octave band restriction, as that is the real intent here. In my experience, only the Chattanooga code writer seems to have the inability to look up and regurgitate the definitions correctly.
TERMS:
Acoustics, Sound & Noise
Background vs. Ambient
Sound Power Level, Sound Pressure Level & Sound Level
Sound Pressure Level Classification & Summing
Spherical, Cylindrical & Plane Waves
Reflection, Refraction, Diffraction & Scattering
Directivity, Arraying & Compressor Limiting
Divergence, Absorption, Transmission & Masking
Threshold of Hearing, Feeling & Pain
Phons, Sones, Weighting & Frequency Bands
Sound Level Meter, Slow, Fast, Impulse, Equivalent Continuous, FFT & RTA
Noise Exposure, Hearing Loss, Protective Noise Levels & Community Noise Measures
Barriers, Enclosures, Silencers, Isolation & Cancellation
Transmission Loss, Insertion Loss, Coincidence & Resonance
Standard Transmission Class, Noise Criterion & Rating Curves, Reflection Build-up & Flanking
Dr. Noelle Currey, P.E.
Acoustical Engineer
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Really? "Jaywalking Smartphone user run over by Carta Electric bus during rock band sound check?"
Is this what we must have a contingency plan for? I certainly hope the small handful of cranky homeowners on the Southside are happy now. All Track29 wanted to do was have some cool bands occasionally come to this town that would have given our arts and entertainment culture a big shot in the arm. I mean, how many has-been Riverbend acts can one endure?
Now with the city officially getting involved, we have attracted the attention of incredibly educated and verbose individuals that can literally write books on the minutiae of sound. Great. Now we can spend untold thousands of dollars and man hours on complex and endlessly confusing legislation in order that a few grouchy folks that go to sleep at 8 p.m. are free to do that every single night of the week.
Just sign me as a ignorant lay person not offended by occasional noisy music and not impressed by the ability to make mountains out of molehills.
Herb Montgomery
Chattanooga
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For the City Council to dismiss the science and engineering of Dr. Currey is just mind boggling. She was always the brain of the class in the school of engineering. Of course, Dr. Currey offered to reproduce the decibels contained in the noise ordinance, and our council does not let science or fact get in the way of their political decisions.
This ordinance is all about political appease for a small group of haves at the Choo Choo.
Allow Dr. Currey to reproduce the sound in decibels for the listening pleasure of our City Council.
April Eidson
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Thank you, Dr. Currey, for your detailed assessment. I must outrank you, sir. My post here on election day (Aug. 6) on the subject, "Do An Environmental Review Before Setting A Noise Ordinance," brought a strange and immediate response.
When I returned from voting I had a message from my councilman (who also is my neighbor) stating that he had missed a couple of my calls recently and requested my telephone number. I had not called him at all since my council communications with him are always via e-mail and responded to that effect on Aug. 7 and told him that I am "in the book."
Within the next day or so at around midnight while all were asleep in this quiet, peaceful area of hayfields, forests and the river, I was visited by a drone with a spotlight focused directly on my home that remained stationary above my front yard long enough for it to extract whatever it may be looking for.
Since I was aware that Senators Diane Feinstein and Rand Paul are involved in seeing to it that drones are prohibited from observing private citizens without a warrant, I plan to follow up on the matter when I visit with my attorney soon.
Charlotte Parton
Chattanooga