Trane TRG-TRC007-EN manual Receiver Sound Correction

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period three

Acoustical Analysis

notes

Receiver Sound Correction

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Receiver sound correction, also called room effect, is 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 in sound is due to a combination of effects, including distance and the absorptive and reflective properties of the surrounding surfaces.

In an outdoor environment, such as a field or parking lot, the absorption of sound is nearly perfect. Sound leaves the source in all directions and diminishes as it travels away from the source. Only the portion of the sound that travels in a direct line from the source ever reaches the receiver. In this environment, the receiver sound correction is mainly a function of distance between the source and receiver.

In contrast, sound entering a room bounces off walls and other surfaces. Therefore, the receiver will hear sound reflecting off the surfaces, as well as the sound coming directly from the source. The amount of sound that reaches the receiver is dependent on the size of the room and the absorptivity and reflectivity of the surfaces in the room. For example, in a completely “hard” room (with concrete walls and floors and no furnishings) the room effect is very small. Conversely, in a “soft” room (with carpeted floors and wall coverings) the room effect can be quite substantial. Receiver sound correction will nearly always result in a reduction in sound level in each octave band.

Sound spreading refers to the reduction of sound energy as a listener moves away from the sound source. It is a factor in room acoustics and, typically, is the primary factor in outdoor sound calculations.

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TRG-TRC007-EN

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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 Response Sound Perception Rating MethodsHuman Ear 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