Sound is perceived in different ways by every individual person, so what sounds loud to you may be quiet to others. Our perception of what constitutes as ‘noise’ is affected by subjective factors. These include the type of noise (one person’s music might be another person’s noise), our mood, the time of day, background noise levels and our expectations. Sudden noises such as a motorbike exhaust or screeching brakes can be more disturbing than steady or expected noises. Frequency of noise may also have different impacts.