Trane TRG-TRC007-EN manual Glossary

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Glossary

hertz (Hz) The unit of measure for frequency. One hertz is equal to one cycle per second.

insertion loss (IL) The difference in sound pressure measured in a single location, with and without a noise control device (installed between the source and receiver) in place.

near field The area adjacent to the source where sound does not behave as it would in a free field, due to the fact that the source does not radiate sound equally in all directions.

NEBB National Environmental Balancing Bureau (www.nebb.org)

noise Unwanted or obtrusive sound. Generally, people object to sound when it interferes with speech, concentration, or sleep.

noise criteria (NC) A single number used to describe sound in a room. It uses a series of curves for plotting sound pressure by octave band and determining the NC value.

noise reduction (NR) A term used to measure the effect of a barrier on reducing the amount of transmitted sound. It is the difference between sound- pressure measurements taken on each side of a barrier.

noise reduction coefficient (NRC) A single number used to describe the sound-absorbing characteristics of a material. It is the arithmetic average of the absorption coefficients for the 250, 500, 1,000 and 2,000 Hz octave bands.

octave band A range of frequencies that is defined such that the highest frequency in the band is two times the lowest frequency. The octave band is identified by its center frequency.

phon A unit of measure, using a logarithmic scale, used to describe the loudness of a sound.

pitch A subjective quantity used to describe a sound. It is primarily based on frequency, but is also dependent on sound-pressure level and composition. Pitch is not measured, but is described with terms like bass, tenor, and soprano.

receiver sound correction The relationship between the sound energy (sound power) entering the room and the sound pressure at a given point in the room where the receiver hears the sound. This reduction is due to a combination of effects, including distance and the absorptive and reflective properties of the surrounding surfaces. Also called room effect.

reflected sound The sound that bounces off, or is reflected by, a barrier back toward the source.

regenerated sound The noise caused by turbulent flow in air and water systems.

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Contents Air Conditioning Clinic Fundamentals of Hvac Acoustics Business Reply Mail One of the Fundamental Series Comment CardFundamentals of Hvac Acoustics Fundamentals of Hvac Acoustics PrefaceContents TRG-TRC007-EN Fundamentals of Sound Fundamentals of SoundWhat is Sound? What is Sound?Sound Wave and Frequency Wavelength Broadband Sound and Tones Broadband SoundOctave Bands Octave BandsLogarithmic sums One-Third Octave Bands Sound Power and Sound Pressure Sound Power and Sound PressureAn Analogy Decibel DB = 10 log10 ´ log Logarithmic ScaleEquation for Sound Pressure Equation for Sound Power50 dB + 44 dB = 51 dB Logarithmic Addition of DecibelsHuman Ear Sound Perception Rating MethodsHuman Ear Response Loudness Contours Single-Number Rating Methods Response to TonesSingle-Number Rating Methods Sound Perception and Rating Methods C WeightingWeighting Example Weighting Noise Criteria NC Curves NC-39 Room Criteria RC Curves MPa DB ref Pressure Sound Perception and Rating Methods RC-31 R Phon and Sone Octave-Band Rating Method Octave-Band Rating MethodAcoustical Analysis Acoustical AnalysisSetting a Design Goal Setting a Design GoalAcoustical Analysis Source-Path-Receiver Analysis Acoustical AnalysisSource-Path-Receiver Model Airborne Typical Sound PathsExample of Multiple Sound Paths Examples of a Single Sound PathIdentifying Sound Sources and Paths Sound-Path Modeling Modeling Sound PathsSupply Algorithms for Sound-Path Modeling Computerized Analysis Tools Terms Used in Sound-Path Modeling Attenuation and RegenerationSound Transmission Insertion loss IL Noise reduction NR Transmission loss TL Absorption Reflected Sound Receiver Sound Correction Equipment Sound Rating Equipment Sound RatingFields of Measurement Free FieldDistance Correction in a Free Field = L p1 20 logLot Near Field Reverberant Field Semireverberant Field Hvac Equipment Sound Rating Rating Hvac EquipmentReverberant-Room Method Free-Field Method Industry Standards Ducted Air-Handling Equipment Air Handler Test Configurations Former Methods of Sound Testing ARI Standard Sound Power by Octave Band Review-Period One ReviewNoise criteria NC Room criteria RC Review-Period TwoReview-Period Three Review-Period Four Review Questions for Period QuizOctave-band frequency, Hz Answers Glossary Glossary Room effect See receiver room correction Glossary Trane
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