Vehicle headrest

A vehicle headrest comprising:

• a main body having a receiving chamber, and including a first sound hole penetrating thereon;
• and
• a speaker module at least partially received in the receiving chamber, including:
• a housing fixed to the main body, including a sound outlet penetrating thereon;
• a speaker unit received in the housing, including a diaphragm configured to vibrate to generate sound wave transmitted to outside through the sound outlet;
• an acoustic inverting tube having a first opening and a second opening located on both ends;
• wherein
• a coupling back cavity isolated from the sound outlet is enclosed by the diaphragm and the housing;
• the housing further comprises a back sound hole communicated with the coupling back cavity;
• the acoustic inverting tube is received in the coupling back cavity;
• the first opening is communicated with the back sound hole;
• the second opening is communicated with the coupling back cavity;
• the first sound hole is communicated with the back sound hole;
• sound wave emitted from the back sound hole has a first sound phase, sound wave emitted from the sound outlet has a second sound phase, a difference between the first sound phase and the second sound phase is in a range of 2π/3-4π/3.