Resonance

• Refrigerators need a solid footing in order to function quietly. If the refrigerator is not balanced correctly, it will vibrate while the motor and compressor are in operation. These vibrations can generate a harmonic in fixtures and other objects around the unit, causing a high-pitched sound. This resonance can be solved either by adjusting the feet on the refrigerator to seat it correctly, or moving the objects the refrigerator is vibrating.
  
  

The Motor

• The motor in a refrigerator contains moving parts that spin at a high speed. As the motor spins, it emits a high-pitched sound that is only audible to the upper register of hearing; making it audible to children and some adults with good hearing. This is due to the frequency at which the motor vibrates, generating high-frequency sound waves. The sound is similar to that of computer cooling fans and power supply units.
  
  

Compressor

• The compressor is part of the technology used to keep a refrigerator cold. It compresses the coolant before pushing it into the expansion chamber and thus enables the refrigerator to remove heat from the air inside the main body of the unit. This generates heat and causes expansion in the material of the compressor when it is working. As the compressor warms and cools, it will sometimes emit a high-pitched sound.
  
  

Warning

• Refrigerators are not inherently silent devices. When a refrigerator is working, it will produce some noise as a by-product. This is inevitable and should not be considered a defect in the product. However, if the refrigerator makes a high-pitched sound that is too unbearable and all attempts to resolve the issue, such as seating the unit solidly, have been attempted, consider contacting the manufacturer to discuss the problem. They may be able to offer advice.