1 system A/C tune-up. Left filter for the owner, cleared drain and clean condenser coil. I could not hear whistle noise/cricket noise. Only thing is some vibration in the walls in the bedroom. The owner told me about the dirty sock syndrome smell. I could not smell it and owner state it's only in heating mode. My only suggestion is installing APCO in the light system in the coil and the supply plenum. System is cooling at this time