Acoustic Modeling
A process using computer software to emulate an existing or future state of the sound environment or soundscape; a typical noise model displays noise contours so that levels of equal decibels are connected by lines.
Air Installation Compatible Use Zones Program (AICUZ)
A DoD Program that promotes long-term compatible land use on and in the vicinity of air installations by encouraging State and local governments to adopt enabling legislation and compatible land use regulations into their land use planning and control processes and by partnering with communities and other eligible entities to protect land through restrictive use and conservation easements.
Ambient Noise
The total of all noise in the environment, other than the noise from the source of interest. Also known as background noise.
An emotional and attitudinal reaction from a person exposed to noise used as primary indicator of community response. Annoyance attempts to account for all negative aspects of effects from noise, e.g., increased annoyance due to being awakened the previous night by aircraft, and interference with everyday conversation.
A-Weighted Decibels (dBA)
Sound level in decibels that closely corresponds with the human ears sensitivity to medium range frequencies by de-emphasizing low and high frequencies. This weighting helps quantify a noise with a wide range of frequencies into a single number representing the sound pressure level. A-weighting is appropriate for transportation noises such as aircraft overflight and vehicle traffic noise. See also "C-weighted Sound Level." (See ANSI S1.1 for scientifically agreed upon definition.)



C-Weighted Decibels (dBC)
Sound level in decibels where weighting is applied to intense low-frequency noise that can cause vibrations. C-weighting does not apply adjustments to noise signals over most of the audible frequencies, but does apply small adjustments to the very low and very high frequencies. C-weighting is appropriate for impulsive sounds, such as sonic booms and the deployment of large caliber weapons. When experienced indoors, impulsive sounds can create secondary noise from rattling and vibrations of the building (see also CSEL and CDNL). (See ANSI S1.1 for scientifically agreed upon definition.)
Compatibility Guidelines
Recommendations for land use compatibility within Noise Zone areas on and surrounding military installations, ranges, and airfields based on the specific type of land use and a range of sound exposure levels. Land use guideline recommendations vary based on the type of noise source (i.e. aircraft, traffic, weapons and explosives).
Community Involvement Program
A carefully designed program that uses a variety of techniques, and that, in addition to informing the public of possible decisions and their potential consequences, provides opportunities for consultation with the public, and considers the public's views before making decisions and taking actions.
Community Planning and Liaison Officers
An individual representing a military installation or range that serves as a bridge between the installation and the community, local governments, and private stakeholders with regards to compatibility of development projects. The CPLO represents the installation commanding officer by meeting with elected officials, regional and community planners, zoning and code enforcement staffs, school board members, utility district managers, local Chamber of Commerce directors and staff, and non-profits groups including environmental, conservation, and natural resources organizations. The CPLO manages installation encroachment management programs which include Air Installations Compatible Use Zones (AICUZ) and the Range Air Installations Compatible Use Zones (RAICUZ) programs.
Complaint Management Systems
A program designed to input, track, and respond to noise complaints which typically include toll-free complaint hotlines, a complaint webpage, and mechanisms for follow-up and investigation of complaints. A well-organized noise complaint management program at an installation can affect negative attitudes towards the offending noise as well as try to reduce the noise exposure.


Day-Night Average Sound Level (DNL)
A 24-hour average sound level for a given day after the addition of a 10 dB weighting is added to account for the increased sensitivity of people to noise from such things as aircraft operations, for sound levels that occur between the hours of 10 p.m. to 7 a.m., because ambient sound levels at night are typically lower than during the daytime hours. (See ANSI S1.1 for scientifically agreed upon definition.)
Decibel (dB)
A logarithmic unit of measure used to describe the intensity or loudness of sound.


Incompatible land uses and habitat loss near and adjacent to installations, ranges, and operating areas which threaten the military's ability to provide the most realistic training.


Number of complete oscillation cycles per unit of time. The unit of audio frequency is the Hertz (Hz), which represents one cycle per second.




Inert Ammunition
Ammunition used for military training and weapons function testing which contains no explosive charge.
Impulsive Sound
Noise of short duration (typically less than one second), especially of high intensity, abrupt onset and rapid decay, and often rapidly changing spectral composition. Impulse noise is characteristically associated with sources such as explosions, target impacts, the discharge of firearms, sonic booms, and many industrial processes.


Joint Land Use Study
A cooperative planning effort conducted as a joint venture between an active military installation, surrounding jurisdictions, state and federal agencies, and other affected stakeholders to address all compatibility around military installations.



Land Use Compatibility
Ensures land-uses on and off an installation are compatible with the current or anticipated military noise environment. In some cases, the annual sound exposure level may be too high to support noise-sensitive land uses such as schools, daycare centers, or residential development. Thus, compatible land uses such industrial, commercial, or agricultural are encouraged. DoD works closely with states, counties, and communities in cooperative land use planning efforts to ensure land use compatibility and limit noise exposure.


Industry standard units of measure and methods of describing noise that ensure all federal, state, and local agencies as well as industry have a standard approach to describing and addressing noise.
Military Noise
Unwanted sound generated from the operation of military vehicles, weapons or weapons systems (e.g., aircraft, small arms, tank guns, artillery, missiles, bombs, rockets, mortars, and explosives).
Military Training Routes (MTRs)
Corridors of defined airspace used by military aircraft to maintain proficiency in tactical flying.


National Environmental Policy Act (NEPA)
A federal law that requires federal agencies to assess the environmental effects of their proposed actions prior to making decisions. The range of actions covered by NEPA is broad and includes making decisions on permit applications, adopting federal land management actions, and constructing facilities. Using the NEPA process, agencies evaluate the environmental and related social and economic effects of their proposed actions. Agencies also provide opportunities for public review and comment on those evaluations.
Noise is any unwanted sound. The issue of noise is very subjective, and is typically influenced by an individual's experiences and sensitivity. Both terms, noise and sound, are used in this instruction, depending on the context of the discussion.
Noise Exposure
The cumulative acoustic stimulation reaching the ear of a receiver, over a specified period of time (e.g., a work shift, a day, or a lifetime).
Noise Level Reduction (NLR)
The difference, measured in decibels, between the A-weighted sound level outside a building and the A-weighted sound level inside a designated room in the building. The NLR is dependent upon the transmission loss characteristics of the building surfaces that are exposed to an exterior noise source, the particular noise characteristics of the exterior noise source, and the acoustic properties of the designated room in the building.
Noise Mitigation
These are measures that can be taken to reduce or avoid noise exposure. For example, mitigating the effects of aircraft noise on sensitive land uses such as schools, residential areas, and churches can take many forms, including modification to time of day or frequency of use, flight path parameters (location, altitude, etc.), or changes to the listener's environment (building insulation).
Noise Study
A comprehensive analysis of noise associated with specific or multiple military activities at a given installation, range, or airfield.



Peak Sound Level
Peak is a single-event (instantaneous) sound pressure level without weighting.



Range Air Installations Compatible Use Zones (RAICUZ)
A Navy-specific compatible land use program similar to the DoD AICUZ program that includes air-to-ground ranges and airspace in the vicinity of naval range installations, in addition to air installations.
Range Compatible Use Zones (RCUZ)
A Marine Corps-specific program designed to protect the public health, safety, and welfare, and to prevent encroachment from degrading the operational capabilities of Marine Corps Range and Training Areas (RTAs), to encompass air-to-ground, ground-to-ground, and laser ranges. Like AICUZ and RAICUZ, the RCUZ provides compatible land use recommendations for noise contours and range compatibility zones (RCZs).


Single Event Sound
Sounds from single events such as the passby of a truck, the flyby of an airplane, or an explosion are all examples of single-event sounds.
Sound Propagation
The process by which sound travels through space or material; may be affected by such things as weather, terrain, and barriers.
Sound Receiver
The individual, community, animal, or object being exposed to a given sound
Sound Source
The origin of a sound or sound producing activity
Supplemental Metrics
Supplemental metrics and tools are additional units of measure and methods of describing noise that can be used to better communicate noise exposure and address the specific concerns to stakeholders.


Military activities or skills, based on specific warfighting goals or strategies, that involve the organized movement of equipment, personnel, or vehicles as conducted in the field of battle.
The physical features of a stretch of land or geographic area, including but not limited to elevation, slope, and geology. Terrain or topographic features can influence sound propagation chararteristics.