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Trane TRG-TRC007-EN manual Source-Path-ReceiverModel, Acoustical Analysis, period three

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Source–Path–Receiver Model

period three

Acoustical Analysis

notes

Source–Path–Receiver Model

source

path

receiver

Figure 37

Predicting the sound level in a given space requires making a model of the system. A source–path–receiver model provides a systematic approach to predict the acoustical characteristics in a space. As the name suggests, this modeling method traces sound from the source to the location where we want to predict the sound (the receiver). How the sound travels between the source and the receiver, and everything it encounters as it travels along the way, constitutes the path.

In the example shown in Figure 37, the source is the fan in the mechanical room. The receiver is the person working in the adjacent office space. The supply duct provides one of the paths for sound to travel from the source to the receiver.

Using such an analysis, the designer can determine the effect of the paths on the sound emanating from the source, and can specify the maximum allowable equipment sound power that will not exceed the sound-pressure target for the space.

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Trane TRG-TRC007-EN manual Source-Path-ReceiverModel, Acoustical Analysis, period three

Contents

Air Conditioning Clinic Fundamentals of HVAC AcousticsOne of the Fundamental Series TRG-TRC007-ENBUSINESS REPLY MAIL BUSINESS REPLY MAILTRANE Attn Applications Engineering 3600 Pammel Creek Road La Crosse WIComment Card Response CardFundamentals of HVAC AcousticsTrane, an American Standard Company One of the Fundamental Series A publication ofFundamentals of HVAC Acoustics Fundamentals of HVAC Acoustics PrefaceA Trane Air Conditioning Clinic Contents period two Sound Perception and Rating Methodsperiod three period fiveTRG-TRC007-EN period one Fundamentals of SoundFundamentals of Sound period oneWhat is Sound? period oneWhat is Sound? Fundamentals of SoundFundamentals of Sound Sound Wave and Frequencyperiod one Fundamentals of Sound Wavelengthperiod one Broadband Sound Broadband Sound and TonesFundamentals of Sound period oneOctave Bands Fundamentals of Soundperiod one Octave BandsFundamentals of Sound period oneOctave Bands Octave bands compress the range of frequencies between the upper and lower ends of the band into a single value. Sound measured in an octave band is the logarithmic sum of the sound level at each of the frequencies within the bandFundamentals of Sound One-ThirdOctave Bandsperiod one Sound Power and Sound Pressure Sound Power and Sound PressureFundamentals of Sound period oneAn Analogy Fundamentals of Soundperiod one K Correlates to bulb wattagedB = 10 log10 DecibelFundamentals of Sound period oneLogarithmic Scale Fundamentals of Soundperiod one ratioEquation for Sound Power = 10 log10= 20 log10 Equation for Sound PressureLogarithmic Addition of Decibels 50 dB + 44 dB = 51 dBFundamentals of Sound period oneperiod two Sound Perception and Rating MethodsSound Perception and Rating Methods period twoLoudness Contours period twoSound Perception and Rating Methods Response to Tones Single-NumberRating MethodsSound Perception and Rating Methods period twoSound Perception and Rating Methods A-B-CWeightingperiod two Sound Perception and Rating Methods A-WeightingExampleperiod two Sound Perception and Rating Methods A-Weightingperiod two Sound Perception and Rating Methods Noise Criteria NC Curvesperiod two Sound Perception and Rating Methods period twoNoise Criteria NC Curves NC-39Sound Perception and Rating Methods Room Criteria RC Curvesperiod two Sound Perception and Rating Methods period twoRoom Criteria RC Curves dB refperiod two Sound Perception and Rating MethodsnPerceptible vibration RV The sound level in the octave bands between 16 Hz and 63 Hz falls in the shaded regions A and B. These regions indicate sound-pressurelevels at which walls and ceilings can vibrate perceptibly-rattlingcabinet doors, pictures, ceiling fixtures, and other furnishings in contact with them Sound Perception and Rating Methods period twoRoom Criteria RC Curves RC-31RSound Perception and Rating Methods Phon and Soneperiod two Octave-BandRating Method Sound Perception and Rating Methodsperiod two Octave-BandRating Methodperiod three Acoustical AnalysisAcoustical Analysis period threeSetting a Design Goal period threeSetting a Design Goal Acoustical AnalysisSetting a Design Goal When defining the acoustical design goal for an outdoor environment, to meet a local noise ordinance for example, the A-weightedscale is typically used. This generally takes the form of a maximum A-weighted sound-pressurelevel at the lot line of the propertyAcoustical Analysis period threeAcoustical Analysis Acoustical Analysisperiod three Source-Path-ReceiverAnalysisAcoustical Analysis Source-Path-ReceiverModelperiod three Typical Sound Paths Acoustical Analysisperiod three IAirborneExamples of a Single Sound Path Example of Multiple Sound PathsAcoustical Analysis period threeIdentifying Sound Sources and Paths Acoustical Analysisperiod three packaged rooftop air conditionerModeling Sound Paths Acoustical Analysisperiod three Sound-PathModelingAcoustical Analysis period threeExample of Multiple Sound Paths supplyAcoustical Analysis Algorithms for Sound-PathModelingperiod three Acoustical Analysis Computerized Analysis Toolsperiod three Attenuation and Regeneration Acoustical Analysisperiod three Terms Used in Sound-PathModelingAcoustical Analysis Sound Transmissionperiod three Acoustical Analysis period threeSound Transmission IInsertion loss IL INoise reduction NRAcoustical Analysis Absorptionperiod three Acoustical Analysis Reflected Soundperiod three Acoustical Analysis Receiver Sound Correctionperiod three period four Equipment Sound RatingEquipment Sound Rating period fourperiod four Free FieldEquipment Sound Rating Fields of Measurement= Lp1 20 log10Distance Correction in a Free Field Equipment Sound RatingEquipment Sound Rating period fourDistance Correction in a Free Field Lp2 = 95 dB - 20 log10 120 ft / 30 ft = 83 dBEquipment Sound Rating Near Fieldperiod four Reverberant Field Equipment Sound Ratingperiod four source reflective wallsEquipment Sound Rating Semireverberant Fieldperiod four Rating HVAC Equipment Equipment Sound Ratingperiod four HVAC Equipment Sound RatingEquipment Sound Rating Reverberant-RoomMethodperiod four Equipment Sound Rating Free-FieldMethodperiod four Equipment Sound Rating Industry Standardsperiod four Ducted Air-HandlingEquipment Equipment Sound Ratingperiod four supply-airoutletEquipment Sound Rating Air Handler Test Configurationsperiod four Former Methods of Sound Testing Equipment Sound Ratingperiod four I ASHRAE generic fan algorithmARI Standard Equipment Sound Ratingperiod four IUses reverberant- room methodSound Power by Octave Band Equipment Sound Ratingperiod four 1 2 3period five ReviewReview period fiveperiod five Review-PeriodTwoReview TRG-TRC007-ENReview Review-PeriodThreeperiod five Review Review-PeriodFourperiod five period five ReviewnTrane Acoustics Program TAP Questions for Period QuizQuestions for Period Quiz Questions for PeriodQuestions for Period 7True or False Sound can only travel from a source to the receiver along one pathAnswers Glossary Glossary hertz Hz The unit of measure for frequency. One hertz is equal to one cycle per secondGlossary reverberant field A uniform, or diffuse, sound field that is the opposite of a free field. In a perfectly reverberant field, the sound-pressurelevel is equal at all pointsGlossary the receiver, and everything it encounters as it travels along the way, constitutes the pathLiterature Order Number TRG-TRC007-ENFile Number E/AV-FND-TRG-TRC007-1101-EN