The hardware specifications would help, as axcc123 already said, but I'll take a guess and say that your hardware isn't doing this.
Configure your audio plugin in Project64 via the "Options/Configure Audio Plugin..." setting. Check the "Sync Game to Audio" option, and click OK. But for games like TWINE and Top Gear Overdrive, you do not want this option on. Disable this option if you are having any game compatibility issues, as this option can sometimes cause games to be extremely slow or even unplayable. It depends on the game.
Or it could be your hardware specifications. Your system's sound hardware could be bad, but it may also be, more likely, your emulation speed and poor graphics hardware, causing the emulation to be slow, including the sound playback.