1、FORD LABORATORY TEST METHOD BV 003-03 SOUND TRANSMISSION TEST Application This test is used to establish the sound insulating or ”sound barrier” capability of instrument panel, floor pan insulating material or fibrous insulating materials. Apparatus Required 1 1 1 2 1 1 1 General Radio Beat Frequenc
2、y Oscillator, Model 1304-B, or equivalent. Fisher Amplifier, Model 50-A, or equivalent. Hewlett Packard Electronic Counter, Model 521 -A, or equivalent. Ballentine Voltmeters, Model 300D, or equivalent. B & K Condenser Microphone, Model 3141, or equivalent. Western Electric Microphone Amplifier, Mod
3、el 200 DE, or equivalent. Sound Transmission Test Chamber (See Figure 1). The sound transmission chamber is designed to provide an infinite baffle for the loudspeaker. The area behind the loudspeaker is lined with sound absorbing material. This material minimizes the amount of sound radiated from th
4、e rear of the loudspeaker. Summary of Test A sample of test material is fastened to the loudspeaker opening of the sound transmission test chamber. Audio oscillator signals are then fed to the loud-speaker. A microphone, centrally located 5 inches away from the front of the chamber, measures the sou
5、nd passing through the material. Test Specimen Cut a test sample from material 24 x 24 inches. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 OC and 50 +/- 5 % relative humidity for not less than 24 h prior t
6、o testing and tested under the same conditions unless otherwise specified. I Date I Action I Revisions I I 2001 10 31 I Revised I Editorial - no technical change A. Cockman I I 2000 08 11 I Revised I Editorial - no technical change A. Cockman I 1992 08 11 I Page 1 of7 FORD LABORATORY TEST METHOD BV
7、003-03 Procedure 1. Assemble equipment as shown in Figure 2. 2. Calibrate the microphone and the decibel meter 3. Fasten the sample to the front of the chamber, over the loudspeaker opening. Using a square retainer plate (frame) about 1 inch wide on each of four sides, hold the sample firmly against
8、 the chamber. This frame is fastened just tightly enough to hold the test material firmly without compression. Test must be performed in a very low noise environment - at least 10 decibels lower than lowest transmission level measured. 4. Centrally locate the microphone outside the sample 5 inches a
9、way from the front of the chamber. 5. Set the oscillator to 400 C.P.S. and adjust the amplifier output to 1.5 volts. Do not change the amplifier setting after this adjustment. 6. Set the oscillator to each of the following frequencies (in C.P.S.): 1 O0 200 400 600 800 125 250 450 650 850 150 300 500
10、 700 900 175 350 550 750 950 1 O00 Measure the sound passing through the material at each of the frequencies. Average sound readings at the 21 frequencies to determine the sound transmission rating. Chemicals, materials, parts, and equipment referenced in this document must be used and handled prope
11、rly. Each party is responsible for determining proper use and handling in its facilities. Page 2 of 7 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BV 003-03 SOUND TRANSMISSION TEST Page 3 of 7 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BV 003
12、03 SOUND TRANSMISSION TEST Page 4 of 7 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BV 003-03 SOUND TRANSMISSION TEST Sound Transmission Test Chamber - Microphone in place, 5” from the front of the chamber This test is performed in our Anechoic Room Page 5 of 7 Copynght0
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