1. Sound and the NVH Team Sound and the NVH Team 2005 FSR / DSS Conference Terry Ryan & Mike Yost 2005 FSR / DSS Conference Terry Ryan & Mike Yost

2. To have Sound 3 things must exist 1.A source 2.A path 3.A receiver Sound Fundamentals

3. Source Airborne sound will travel outward from its source

4. Wall of structure. Sound reflecting off a structure will double

5. Wall of structure. Sound reflecting off these structures will virtually quadruple Wall or Fence.

6. Structure Born Sound 1.Transmitted from the SOURCE through a SOLID Object 2.Structure acts like a Speaker 3.Structure borne sound can be audible throughout a room 1.Transmitted from the SOURCE through a SOLID Object 2.Structure acts like a Speaker 3.Structure borne sound can be audible throughout a room

7. Let’s take a moment to get a lay of the land. Here’s our outdoor unit. The Air Handler is in the closet. There are windows here here and here

8. The sound is the loudest in this wall here Listen at the wall here and here at this window. Does it sound similar outside? If all three places sound similar it’s likely airborne If it’s louder inside than outside, it’s structural

9. Can we hear the sound in this wall? We would if Structure Borne. If the sound is in the piping, you may be able to hear it here. At this point our Sound appears to be Airborne.

10. Place a sheet of plywood here. If the sound level decreases, it was Airborne Sound.

11. 1.Compressors having a synchronous speed of 3600 RPM (and loaded around 3300 to 3400 RPM) 2.The outdoor fan motor having a synchronous speed of 1200 (loaded near 1100). Multiply the number of blades on the fan (3) and we get it’s frequency of 3300. 3.The difference between the fan and compressor frequencies cause the beating “waa-waa” sound. Airborne Sound “WAA-WAA”

12. Airborne Sound WAA-WAA

14. Airborne Sound Platform Acts Like Megaphone

15. Structure Borne Sound

18. Hydraulic Hammer

19. Damaged Internal Springs

21. Stethoscope: Looking for source of sound

22. NVH Field Visit Filtered Beats Complaint 2/15/2005 Dave Renegar, Rick St. Mars, Jerry Hoover

23. Hard 90 brazed in-between brick & wall stud space Line Set runs up wall into attic 1-1/8” + 3/8” Line Set runs up wall into attic 1-1/8” + 3/8” Master Bed Room on other side of wall (Where sound is objectionable) Master Bed Room on other side of wall (Where sound is objectionable) 2A7A2048A1000AA 418479L3F 2A7A2048A1000AA 418479L3F

24. First attempt by Installer Compressor replaced once First attempt by Installer Compressor replaced once

25. ISR0063 added inside unit and outside unit Removed mortar from contact with line set ISR0063 added inside unit and outside unit Removed mortar from contact with line set