I have a weird sound from my car air condition, i just need to check if all Rb`s have the same sound or just me. When the air condition is on and car RPM between 850 & 1000, A quite VOoOm sound is heard and you can feel some vibration under your feet. when rpm is more than 1000 the sound disappear, the sound comes only when AC is ON. I start investigating the noise and i when i open the hood and put my hands on the pipes Low and high of the AC, i feel this sound and vibration inside the pipes, i tried to keep the pipes a bit away from the body by putting some rubber, the sound and vibration decreased. why such sound appear at low RPM? every thing in the AC is normal. I went to the dealer service center and they though it was the AC compressor, and change it, but the sound still there. they are not that qualified to help. Any pro can help me?