抄録
These days, household affairs such as night time vacuum cleaning and machine-washing have become commonplace because of dense residential areas and diversified living styles, resulting in the increasing necessity for low-noise electrical household appliances. Specifically, noise reduction for a compact-size electrical vacuum cleaner is difficult because it incorporates a high-speed motor in it. Catalog specifications itself cannot provide purchasers with real sensation of noise. Accordingly, they result in confirming the actual noise when they use it at home. Human also discriminates noises in terms of sound quality. Our experiment confirmed that the improvement in sound quality of noises radiated from the vacuum cleaner considerably contributes to the psychological noise reduction. Based on the results, we have installed a specially designed acoustic filter, a Helmholz resonator, into a vacuum cleaner, which is capable of absorbing harmonic high-level noise components involved in the motor rotation, thus alleviating users' sense of discomfort against the noises from the vacuum cleaner.
