Transformers typically generate noise in the range of 50 to 2000 Hz. Background noise generally tends to concentrate in the lower frequency range. Due to the high level of background noise, the noise level of transformers is often measured as being higher than it actually is, preventing accurate results. Additionally, if materials with low absorption values at low frequencies are used on the walls of the test room, the transformer’s noise can reverberate within the space, negatively impacting the measured sound level. At Pechom, considering all these factors, we successfully insulate transformer test rooms using materials and systems specifically developed for transformers that provide high absorption performance at low frequencies. By minimizing background noise and maximizing the absorption value within the environment, we ensure that tests are conducted in a reliable manner.