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Building noise localization log: use this sound-event log to help determine the source of building noises or sounds. Using a log to record observations of noises related to time of day, weather, equipment operation, building occupancy and activities can help determine where building sounds originate: a process of sound localization.
In this article series we provide a series of detailed articles on reducing unwanted building noise levels through building design, insulation, sound isolation, and noise barriers. Our page top table of relative sound levels (left) is from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons
Two general approaches to tracking down the source of noises in buildings
Where is noise loudest? Using people with acute hearing and/or supplementing with noise amplification equipment (some very inexpensive devices are available and can help, such as from Radio Shack), explore the building inside and out to get closest to the sound source. Add use of a mechanic's stethoscope.
What conditions seem to correlate with noise production: Keep a log of factors that can help identify noise source such as
Time of day
Weather conditions: temperature swings, rain, wind, wind direction, wind force
External conditions: equipment operating in the neighborhood or at neighbors
Internal building conditions: equipment turning on or off (try leaving suspect equipment turned off)
For unidentified sound sources, general advice on tracking down the source and cause of annoying building sounds and noises includes a procedure similar to our ODOR DIAGNOSIS CHECKLIST, PROCEDURE.
To track a mystery-noise or sound to its source, try keeping a noise log, noting the following items - (print and use the table below if you find that helpful):
You can print this web page directly, or save it to a PDF file, or if you prefer, see
[Print this Page for use as a sound event diagnostic log]
Date & Time
Noise Observed: dates, times, description
The date and time of the noise at each occurrence, especially when it was first observed
Who hears the noise? People's hearing ability varies widely; use someone with acute hearing to help track down noises; don't rule out medical conditions that can cause people to perceive noises that are neurological or bodily in origin
Activities: who is present in the building, people, animals; walking or moving around, using equipment, using plumbing, etc.
Apparent noise location, direction:
Probable noise origin by location: differences in noise perception between what is observed indoors, at different indoor locations, and outside. Where is the noise loudest?
Noise properties: describe the noise
Noise occurrence correlated with any of the items in our noise checklist
Noise type: buzzing, hissing, bubbling sounds may be identified by matching what you hear to items in our List of Building Noises by Sound Source or Sound Types found beginning just below on this page.
Building Mechanical Equipment: air conditioner, heat, fans, water pump, water softener, appliances, etc. on or off at time noise was observed
What equipment is operating or turned off in the building; equipment may itself be making noise or heating or cooling equipment can cause temperature changes that lead to noises
What weather conditions might be pertinent such as wind, wind direction, temperature, temperature changes or shifts, rain, or freezing conditions
Site & neighbors:
Site activities: are there possible noise sources outdoors but near the building from neighboring buildings, power transformers, neighboring businesses, equipment, etc.
Sun direction and sunlight levels - sunlight can correlate with thermal expansion of materials and thus noises
Temperature changes: by noting temperatures and temperature changes we might trace noises to creaking, popping, squeaks etc. caused by thermal expansion and contraction of materials or to operating of heating or cooling systems
Wind conditions: is wind blowing? From what direction, at what strength; does wind correlate with noise occurrence?
Building modifications, changes:
What has changed in the building that might be relevant such as installation or removal of equipment
Question: what instrument can I use to track a noise to its source ? A mechanic's stethoscope is too limited
Is there an instrument available that could be used to locate sound source? The common mechanical stethoscope is not very effective in locating the constant 24 hr humming sound in my home. The sound is a droning 60 HZ constant, but there are other sources harmonizing with it. I managed to eliminate the sound sources one by one and I am now left with the last two major ones. I badly need some help because my health is starting to go.
- C.M. 4/23/2013
Reply: six approaches used by acoustical engineers to pinpoint or localize noise and sound sources
I agree that a stethoscope is not where one would start in finding the source of a widespread building noise.
A mechanic's stethoscope is useful principally when one is checking specific machinery, surfaces, or objects for sound emanation. This tool does not quickly direct one to an area of a building when a noise is heard as ambient or widespread.
For moving from an ambient widespread noise to a source requires a combination of careful listening with methodological investigation such as keeping a noise-event log to relate sounds to changing conditions of time, weather, equipment in or out of operation, nearby activities, combined as well with visual inspection and occupant interviews.
Directional microphones are sold by a variety of vendors who supply some quite different models and technologies. But I'm not sure an affordable directional microphone will do a great job tracking down a building noise source.
I have not found good success at tracking down a "general" noise using pressure-gradient-type directional microphones - the common instrument used to pick up remote conversations or sounds. Since directional microphones pick up noise from any direction you can be fooled if a sound coming from direction A is bouncing off of a hard surface B at which you have aimed the device.  In other words some skill and experience are needed to use such tools. soundonsound.com has an excellent, if technical, explanation of the types of microphone and their sensitivity to the actual direction of sound emanation.
My reading about directional mikes suggests that equipment is intended for the recording industry or for the hearing aid industry but not for sound localization.
Engineers use about six different methods to pinpoint the origin of sounds, procedures described by Mehdi Batel et als (2003) . Six approaches to noise localization used by acoustic experts include
Sound pressure mapping
Sound intensity and selective intensity
Near-field acoustic holography
Non-stationary acoustic holography
Beamforming (phased array technique)
Inverse Boundary Element Methods (IBEM)
These approaches were tested and described for industrial applications such as the automotive industry and it does not appear that these methods, including a relatively new beamforming microphone array methods, are being used in residential noise complaint applications. Some are quite costly, some are quite time-consuming to use. Beamforming for sound localization can examine large objects (a car in a wind tunnel, for example) and is a more rapid process that might work in or at buildings, particularly where we are less interested in the precise sound level and mostly interested in finding the sound source.
If you can find an engineer who has access to beamforming sound-localization equipment, and if her employment and equipment costs are justified by your local noise problem, that approach may be what you need.
But before trying that more sophisticated and costly approach, a thoughtful site interview, investigation, and some data logging can very often find the source of a building noise. Perhaps these items will help you
Keep us informed on what success you have, as that may assist other readers.
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Acoustical Society of America - http://asa.aip.org/ Elaine Moran, ASA Office Manager, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502
516) 576-2360, FAX: (516) 576-2377 email: email@example.com.
ASA is an excellent source of noise and sound standards. Quoting from the associations history page:
"From the Society's inception, its members have been involved in the development of acoustical standards concerned with terminology, measurement procedures, and criteria for determining the effects of noise and vibration. In 1932, The American National Standards Institute (ANSI), then called the American Standards Association, appointed the Acoustical Society as sponsor of a committee, designated as Z-24, to standardize acoustical terminology and measurements. The work of this committee expanded to such an extent that it was replaced in 1957 by three committees, S1 on Acoustics, S2 on Mechanical Shock and Vibration, and S3 on Bioacoustics, with a fourth, S12 on Noise, added in 1981. These four committees are each responsible for producing, developing a consensus for, and adopting standards in accordance with procedures approved by ANSI. Although these committees are independent of the Acoustical Society, the Society provide
s the financial support and an administrative Secretariat to facilitate their work. After a standard is adopted by one of these committees and approved by ANSI, the Secretariat arranges for its publication by ASA through the American Institute of Physics. The ASA also distributes ISO and IEC standards. Abstracts of standards and ordering information can be found online on the ASA Standards Page. More than 100 acoustical standards have been published in this way; a catalog is also available from the Standards Secretariat (631-390-0215; Fax: 631-390-0217). The Society also provides administrative support for several international standards committees and acts as the administrative Secretariat (on behalf of ANSI) for the International Technical Committee on Vibration and Shock (TC-108)." - http://asa.aip.org/history.html
ANSI/ASA S12.60, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools, 2002.
 Connelly, Maureen, Hodgson, Murray, "Thermal and Acoustical Performance of Green Roofs", Sound Transmission Loss of Green roofs, [presentation, Session 1.5], Greening Rooftops for Sustainable Communities, conference, awards, trade show, Baltimore MD, 30 April-2 may 2008. Web search 4/3/2011 original source: http://commons.bcit.ca/greenroof/publications/
2008_grhc_connelly_hodgson.pdf. These authors provide an excellent bibliography of references for sound transmission in buildings, including some of the references cited just below:
Sharp, BH 1973, Study of Techniques to Increase the Sound Insulation of Building Elements. U.S. Department of Commerce PB-222 829, Washington.
Sharp, BH & Martin S 1996, "The Measurement of Aircraft Noise Reduction in Residences", Proceedings of Inter-Noise, Liverpool, 1996, pp. 2747-2752.
Friberg, R 1973, "Transmission Loss and Absorption Factors for Corrugated Steel Roofs, Insulation on the Outside", Proceedings of Inter-Noise, Copenhagen, 1973, pp. 213-217.
 Colbond, EnkaTech Note, "Acoustical Benefits of Roof Underlayments", Colbond Inc., PO Box 1057, Enka NC 28728, Tel: 800-365-7391, website: www.colbond-usa.com web search 4/3/2011, original source: http://products.construction.com/
 General Steel Corporation, "The Facts About the Acoustical Performance of Metal Building Insulation 2", Sound Transmission Class, General Steel Corporation, 10639 W. Bradford Road, Littleton, CO 80127, web search 4/3/11, original source: http://www.gensteel.com/insulation_facts-5a.htm
 North American Insulation Manufacturers Association NAIMA, "Insulation Facts #58: The Facts About the Acoustical Performance of Metal Building Insulation", NAIMA, 44 Canal Plaza, Suite 310, Alexandria VA 22314, tel: 703-684-0084, website: http://www.naima.org/
 Sarah Hager Johnston, Peregrine Information Consultants, Tel: 860-676-2228, Website: www.peregrineinfo.com Email: firstname.lastname@example.org
Research and writing for insurance, risk management, safety & health, business, and medical professionals. Quoting: Peregrine Information Consultants provides customized secondary research, technical information, and standards, news, current awareness services, writing, and editing to support U.S. clients in property/casualty insurance, risk management and loss control, occupational safety and health, consumer safety, business, retail, manufacturing, and other industries.
Developments in Noise Control, NRCC, National Research Council, Canada, suggestions for noise control, sound transmission through block walls, plumbing noise control, noise leaks, and sound control advice. Web search 01/17/2011, original source: https://www.nrc-cnrc.gc.ca/eng/ibp/irc/bsi/90-noise-control.html
Thanks to audiologist Cheryl P. Harllee, licensed hearing specialist, for discussing noises and noise problems in preparation for this article. Ms. Harllee can be located at the Village Hearing Center, 249 U.S. Highway One, Tequesta FL 33469 561-744-0231
 "Localization of a source of sound in a room," W.M. Hartmann, Proc. Audio Engr. Soc. Eighth International Conference, ed. S. Pizzi, pp 27-32, AES, New York (1990).
 "Auditory Localization in rooms," W.M. Hartmann, Proc. Audio Engr. Soc. Twelfth International Conference, ed. S. Bech pp 34-39, AES, New York (1993). "Listening in a Room and the Precedence Effect," W.M. Hartmann, in
 Binaural and Spatial Hearing} ed. R.H. Gilkey and T.B. Anderson, pp 191-210, L. Erlbaum Associates (1997).
 Medhi Batel et als., "Noise Source Location Techniques - Simple to Advanced Applications", Sound and Vibration, March 2003, retrieved 4/23/2013 original source www.sandv.com/downloads/0303bate.pdf [copy on file as Noise_Source_Location_Techs0303bate.pdf]
Thanks to reader Sue Hazeldine, from the U.K. for discussing how she tracked down a whistling chimney noise to an antique hanging sign on the building exterior - 01/19/2010.
Thanks to reader Michael Anderson, 8 May 2009, for discussing clicking sounds coming from air conditioning equipment.
Thanks to reader Erna Ross who described loss of sleep due to a hissing noise at her home 06/15/2008.
Marpac, produces white sound generators, a product that they identify as the Marpac sound conditioner. Marpac can be contacted at http://www.marpac.com/ or contact the Marpac Corporation,
P.O. Box 560 Rocky Point, NC 28457 Phone: 800-999-6962 (USA and Canada) Fax: 910-602-1435 1-910-602-1421 (worldwide), 800-999- or email: email@example.com
Sound Oasis sound conditioners are produced by Sound Oasis: http://www.sound-oasis.com/ email: firstname.lastname@example.org or 1-866-625-3218
Barrier Ultra-R super high-R building panels, produced by Glacier Bay, use Aerogel and are rated up to R-30 per inch, or in Barrier Ultra-r™ panels, R-50 per inch. The company also produces acoustic panels that are Ultra-db resistant and lightweight. Unlike the appliance insulation panels discussed in the original Q&A above on miracle insulation, these Areogel based panels will continue to retain some, though reduced insulating value if punctured, performing at perhaps R-9 per inch. The product is used in marine refrigerators, but in the future may be available as a residential construction product. The company is researching specialized products in medical, transportation, and aerospace applications. Contact: Glacier Bay, Inc., 2930 Faber Street, Union City, CA 94587 U.S.A., (510) 437-9100, Sales and Technical Information - email@example.com
Noise - a Health Problem - http://www.nonoise.org/library/epahlth/epahlth.htm - quoted below
Racket, din, clamor, noise. Whatever you want to call it, unwanted sound is America's most widespread nuisance. But noise is more than just a nuisance. It constitutes a real and present danger to people's health. Day and night, at home, at work, and at play, noise can produce serious physical and psychological stress. No one is immune to this stress. Though we seem to adjust to noise by ignoring it, the ear, in fact, never closes and the body still responds - sometimes with extreme tension, as to a strange sound in the night.
The annoyance we feel when faced with noise is the most common outward symptom of the stress building up inside us. Indeed, because irritability is so apparent, legislators have made public annoyance the basis of many noise abatement programs. The more subtle and more serious health hazards associated with stress caused by noise traditionally have been given much less attention. Nonetheless, when we are annoyed or made irritable by noise, we should consider these symptoms fair warning that other things may be happening to us, some of which may be damaging to our health.
Protective Noise Levels - 1979, basis for many local noise ordinances and codes - http://www.nonoise.org/library/levels/levels.htm This publication is intended to complement the EPA's "Levels Document,"* the 1974 report examining levels of environmental noise necessary to protect public health and welfare. It interprets the contents of the Levels Document in less technical terms for people who wish to better understand the concepts presented there, and how the protective levels were identified. In that sense, this publication may serve as an introduction, or a supplement, to the Levels Document.
"Measurement of Highway-Related Noise", US Department of Transportation, Federal Highway Administration, http://www.fhwa.dot.gov/environment/noise/measure/chap8.htm
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