Quiet is like good health, and noise is like a disease with deeply hidden causes. Following this model, hiring someone to provide Noise Control is not at all like buying an off-the-shelf exercise bike to keep you healthy and good looking; it is more like hiring a physician to cure your disease. It requires time, thought, and money.

The physician cannot prescribe a cure without first diagnosing the disease, and this is done following a well-established, scientific process having seven steps:

• Take a medical history to define current health status and its weaknesses
• Do a physical exam to document the external symptoms of the disease
• Do lab tests to measure the hidden, internal abnormalities
• Analyze the history, physical, and lab tests to accurately diagnose the disease
• Select, from the countless available treatments, the right combination to reduce the symptoms or cure the disease
• Design the needed treatments and specify the needed medicines
• Follow-up to assure success; re-evaluate and re-prescribe if necessary

It would be unrealistic to ask the physician to “skip all the history, physical, inspection, and testing; just give me a pill to make me better.” If you just have a cold, it may even work; but if its like most serious problems, the odds of a cure will be slim. It is just as unrealistic to ask the Noise Control engineer to skip the interview, inspection, measurements, and analysis, and specify a quick noise control cure - just hang up some foam or fiberglass and hope for the best. It can cost a lot, and it seldom works. A good noise doctor has the knowledge, skill, and experience you need to properly diagnose and cure your noise disease. Ask and expect him to do his job properly. After all, you are paying for it. You deserve to get what you pay for – and what you expect; a cure.

Vibration

The long-continuing oscillating motion of the medium or object when struck or disturbed, like the vibrating motion of the surface of a motor, engine, or machine when it is running.

Impact

The short-term oscillating motion of the medium or object during the short interval after it is stuck or impacted, like the decaying vibration of a bell after it is struck

Vibration Theory

General Vibration Science. The science of vibrating objects or media. The study of their frequency, amplitude, time variations, and associated phenomena like resonance and metal fatigue.

Bio-mechanics

The science which studies the effects of impact and vibration on living things, including human beings [how does long-term truck vibration affect a man’s internal organs: how does the impact of ejection from an aircraft affect his spine?]

Sound

The pressure wave phenomenon which moves outward (propagates) from the vibrating object or medium, through the surrounding air, water, earth, or structure. Sound is usually audible, except for infrasonic and ultrasonic waves. Specialty areas include sonic studies underwater (sonar weapons), in metal structures (metal fatigue), etc. Since sound is a physical phenomenon, it can be measured.

Acoustics, General

The science of sound as it relates to vibration, i.e., of sound frequency, amplitude, time variations, and associated phenomena like standing waves.

Acoustics, of Interior Space

The science which analyzes the behavior of sound inside an enclosed space, like a car, plane, train, or room

Bio-Acoustics

The science which studies the effects of sound and noise on man [what does long term noise do to hearing, mental function, stress, etc.?]

Noise

Noise is simply unwanted sound. There is no distinction on who does not want it, or why they do not want it. It can be noise to a person if it is a nuisance, an annoyance, or is harmful to hearing, well-being, happiness, or health. As the old saying say, “one man’s music is another man’s noise”. Since noise has a large psychological dimension, and psychological reaction cannot always be measured, noise cannot truly be measured. We generally say that sound can be measured but noise can only be assessed; we sort of measure noise when we use the A-scale of a sound meter, which gives readings proportional to perceived loudness

Blast

When people use dynamite to blast out rock, say for a highway or underground parking structure, the resulting blast vibrations can propagate to and damage nearby buildings, cracking plaster as well as foundations

Measurement

We measure when we use microphones, accelerometers, and other transducers, coupled with electronic instruments, to measure the intensity of these phenomena

Analysis

We analyze when we break down the sound or vibration signal into its various frequency components, intensity relationships, and time histories, so its various effects may be predicted and controlled

Control

We control when we find ways to minimize, reduce, or even eliminate a problem sound or vibration

Acoustical Engineering

Using engineering knowledge and experience to measure, analyze, and control sound as it moves through a solid, liquid, or gas

Architectural Acoustics

The scientific and engineering study of acoustics in buildings, particularly the study of sound which one likes and wants to preserve or enhance (improving the sound of speech or music in a theater or auditorium; or adding speaker and amplifier systems to magnify them without distortion

Noise Control Engineering

Using scientific and engineering theory and experience to control sound which one does not like and wants to minimize or eliminate (noise). This may be done in a variety of settings (e.g., an outdoor park, a community, a business or industrial work place, on a plane, train, or automobile, or near a noisy machine)

Vibration Control Engineering

Using scientific and engineering theory and experience to isolate a machine, machine component, building, or other structure from the forces which want to vibrate it. This may involve use of specialized rubber or spring elements, seismic masses, damping compounds, etc. which dissipate the energy or mis-match the frequency

Machine Condition Monitoring

Periodically monitoring the condition of machine bearings, gears, etc. for wear and other factors which lead do deterioration and unplanned shutdowns. It normally requires regular (e.g., monthly) vibration measurements and analyses, and vibration trend analysis, but may also involve oil sampling, thermal sensing, and other technologies

Blast Engineering

Planning blasting operations to minimize blast damage to nearby structures, through the location, weight, and timing of blast elements; monitoring the blast vibrations during blasting to assure that they are within allowable limits; and surveying nearby buildings for crack damage before and after blasting

1. Design it right the first time
   • “Why is it that there is never time to do it right, but there is always time to do it over?” (old engineering aphorism)
   • “Doing it right requires enormous attention to detail
2. 2. Design it “on the cheap” and risk living with ANV problems for years
   • “What idiot designed this acoustical nightmare?!” (a common complaint)
   • “Pay me now, or pay me later!” (like the muffler salesman said)
3. 3. Do A.N.V. measurements, re-design, and rehabilitate the building
   • “It’s going to cost me HOW MUCH to fix this acoustical nightmare?!” (another common complaint)
   • “It costs much more to gut it and start over than it costs to do it right the first time.” (wisdom from a great many years of experience)

1. Designing it right the first time
   • Co-develop, with Owner and A/E firm, proper ANV criteria
   • Measure site ANV parameters or collecting data on anticipated ones
   • Design of structures, surfaces, and materials for proper ANV control
   • Assistance with specifications and contract documents
   • On-site construction observation to correct problems before they arise
   • Follow-up with the Owner to and profit from past mistakes
2. Designing it over when the first time fails
   • Interviews with building occupants to help precisely define problems
   • Building construction inspection to find the reasons for the problems
   • Measure wall, floor, and ceiling noise reduction by ANSI/ISO methods
   • Measure room reverberation time (use pistol source and transient analyzer)
   • Etc.