I've been searching for it for a very long time and can't seem to find any relevant items (I know about the VLC plugin and I don't think it supports sound effects for video games). I need something similar like FMOD or Bass (or an NPAPI wrapper for these two) or a DirectSound NPAPI plugin, or just anything as long as it can support loading .wav, .ogg, .mp3, .m4a, etc. and can play those sounds in multiple instances.
EDIT: The reason I'm trying the NPAPI route is because the Web Audio API isn't really ready for primetime yet. I already tried Chrome's implementation and it has a bit of latency when playing the sounds (and multiple instances of sounds). It's even hard (or maybe impossible) to pause-play sounds with the current API spec. I also tried Flash (via SoundManager 2) and it also suffers from latency. It's fine for games but not good for making music applications such as a drum sampler. I hope this clarifies. (Sorry for my English, it's not my first language)