Emulator

This would be a great feature if possible, but I'm not optimistic.

The delayed sound is absolutely game-breaking, IMO. I'm very picky when it comes to audio. I absolutely cannot stand out of sync audio.

Such as Twilight Princess. The sound is perfectly in sync when using HLE, but it also has other sound glitches that are even worse (uneven sound, missing sound, etc).

LLE solves many of the uneven and missing sounds, but it is completely broken by the fact that the sound is ever so slightly delayed (it can be very slight sometimes, but it is most definitely there). It will take a lot of willpower to play through it while dealing with the delayed audio.

On second thought, I'm not even sure how such a thing would be possible.

The only way to sync the video and audio in this way would be to delay the video, but that would introduce input lag. The emulator is already outputting the sound as soon as it is capable of doing... right?

I don't think that the video has to be delayed, for example the feature in the PCSX2 plugin doesn't do it and still makes possible to "finetune" the the delay of the sound in order to better sync it with the video; but this doesn't mean that it interferes with the video output: it's only a "routine" to play the sound a bit before or a bit later than what's expected by the default setting (150 for PCSX2 - which is a too large value in my opinion aka there's too latency but you can easily finetune it with the slider I mentioned).

Going to agree with the above posts; LLE is the "better" of the two plugins as far as stable audio, but it adds a noticeable delay (and a slight FPS hit). This issue should get a little more attention, because it is notable under normal conditions (be it fixing HLE to be more stable, or reducing the latency on LLE).

I'm using an ASIO 2.0 plugin for my ASUS Xonar Xense, so I know the latency isn't from the OS side of the house either.