The human ear hears the same loudness for sound pressure even though with different decibels for different frequencies. The typical sound pressure is as shown in the table below. For most people, the sound frequencies from 1kHz to 4kHz are the easiest to hear. The measurement of the sound pressure is usually taken from about 3 feet from the source. The strength of the sound decrease with the distance from the source. Sound waves are generated due to a changing of air pressure and travels in all directions. Check also the bearings of the fan motor.

Internal parts that are not easily accessible should be cleaned by qualified technicians. Hence it is always a good practice to clean the air filters regularly. Over time, dirt and other materials may block the movement of the fan blades and the air. The indoor unit or evaporator consists of electronic control, cooling coil, air filters and blower. Check also the bearings of the fan motor which can cause imbalance to the fan. Sometimes, the noise can come from the leaves and other material that block the fan blades from rotating properly, and you can reduce air conditioner noise by cleaning in or around the unit. If the noise comes from the mounting problem, this can be solved else you will need to replace the compressor for good. There are not much you can do to a hermetic compressor as you will not be able to access the internal mechanical parts. Lighted Magnifying Glass That Stays Put.Best Lawn Care Service for Service Dogs.

Cooling fan decibel ratings chart