Assessment of the sound environment inside high speed trains by sound quality design

With the fast development of the high speed train, the major noise sources of the high speed train emit the higher level noise. It is a hot issue to reduce the noise within the high speed train to provide quieter environment for the passenger. The internal noises inside four carriages of high speed trains were measured at three running speeds. Four sound descriptors such as A-weighted sound pressure level, loudness, room criterion, and RC Mark II were used to assess the noises inside high speed trains. It is found that the low frequency compo¬nents of sound pressure level within carriages are dominant. A-weighted sound pressure level underestimates the perceived intensity of low-frequency components. The specific loudness curves are more accurate to measure the perceived intensity of sound pressure level in the whole frequency range. The internal sound environment inside the carriage is judged as questionably acceptable or unacceptable and the components around the octave band center at 2000 Hz exceed the reference values. It is recommended that the noise in the appropriate frequency range should be reduced to enhance the sound quality within carriage.