ACUPRO Version 4 slide show - TFAcoustics · 5 ACUPRO 5 Standards 1. ISO 10534-2, Acoustics-Determination of sound absorption coefficient and impedance in impedance tubes - Part 2:

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ACUPRO 5

Research Foundation

1. Seybert, A.F. and Ross, D.F., Experimental Determination of AcousticProperties Using a Two-microphone Random Excitation Technique, J.Acoust. Soc. Am., 61, 1362-1370 (1977)

2. Chung, J.Y. and Blaser, D.A., Transfer Function Method of MeasuringIn-duct Acoustic Properties, II: Experiment, J. Acoust. Soc. Am, 68,914-921 (1980)

3. Seybert, A.F., Two-sensor Methods for the Measurement of SoundIntensity and Acoustic Properties in Ducts, J. Acoust. Soc. Am, 83,2233-2239 (1988)

4. Tao, Z. and Seybert, A. F., A Review of Current Techniques forMeasuring Muffler Transmission Loss, Proceedings, SAE Noise andVibration Conference, Traverse City, paper 2003-01-1653 (2003)

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ACUPRO 5

Standards

1. ISO 10534-2, Acoustics-Determination of sound absorption coefficientand impedance in impedance tubes - Part 2: Transfer-function method

2. ASTM E1050-98, Standard Test Method for Impedance andAbsorption of Acoustical Material Using a Tube, Two Microphones anda Digital Frequency Analysis System

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ACUPRO 5

ACUPRO Hardware

• Exceeds ISO and ASTM design requirements• Thick-walled, highly damped materials reduce vibration• Precision machining insures plane wave sound field• Microphone mounting is secure and sealed• High output JBL compression driver

JBL 2426JDriver

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ACUPRO 5

Specifications

• Frequency range: 50 Hz – 5700 Hz• Maximum SPL in tube: ~ 150 dB• Ambient noise in tube: < 30 dBA• Microphones: ¼ and/or ½ inch• Tube inside diameter: 34.9 mm• Tube outside diameter: 41.3 mm• Maximum length of sample: 14 cm• Overall length: 1.20 m (with sample

holder)• Total mass: 10.5 kg

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ACUPRO 5

Software Features - General

• Runs under Windows 10• Reads text files from any analyzer• Graphics visualization of all results• Log window tracks history• Hard copy of graphical results• Soft copy of all data in text files• Access to ACUPRO manual

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ACUPRO 5

Sound Absorption Measurement

Sample holder with rigid piston

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ACUPRO 5

Software Features – Absorption Measurement

• Corrects microphone amplitude and phase• Corrects for latent tube absorption• Determines the following properties

Sound absorption coefficientComplex sound reflection coefficientComplex surface impedanceComplex surface admittance

• Outputs data for flow resistivity determination

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ACUPRO Version 5

Material Characterization Module

Correction for microphone amplitude and phase response

Graphical display windows

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ACUPRO 5

Example - Absorption Measurement

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Measurement of Transmission LossACUPRO 5

Optional TL tube

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ACUPRO 5

Software Features – TL Measurement

• Corrects microphone amplitude and phase• Determines transmission loss (TL) of

• Barrier materials• Mufflers and silencers

• Other material properties determinedComplex wave numberComplex material densityComplex sound speed in materialComplex characteristic impedance

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ACUPRO 5

Transmission Loss Module

Files for TL calculation

Properties determined

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ACUPRO 5

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TL (d

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Measured TL of Barrier Material

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ACUPRO 5

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TL (d

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Measured TL of an Expansion Chamber Muffler

20 cm