Emulator

Try using the OpenAL back-end, and tell me if it's still broken. I play the game at 40 - 50 fps all the time and have little to no problems on my PC, though I commonly can hit 60 fps on some stretches of tracks.

I also think you're being a bit misleading; choppy audio is the correct output (except in the OpenAL backend) and by saying it's broken means that something is going wrong. I'd rather have the audio be slow or choppy than outright play at the wrong speed compared to the game.

Even with OpenAL, audio is extremely choppy and massively distorted (tried with different latency settings). Audio is broken because it worked perfectly in Dolphin 3.0 and 3.5. where the game was fully playable with minor slowdown and perfect audio.

In my opinion Dolphin needs to keep some form asynchronous audio (which is a major feature in PS1 and PS2 emulation by the way) or the end user experience for the majority of users will get much worse since nearly all games are affected unless you have a super-ultra high end PC.

Audio stretching cannot be the solution since even turning audio off sounds much better than that.

The issue isn't the audio, the issue is your computer not running full speed.

If you were to run any other emulator below full speed, you would receive similar results. The fact old HLE is speed independent is a bad thing, and it breaks games. If you want to use an older build to improve your experience, that's your prerogative, and definitely justifiable. But to ask for a broken feature to be put back into the emulator is probably not going to happen.

The new audio engine solves a lot of problems but also brings new major issues as well that by far outweigh the benefits. On my PC and on the majority of end user systems the audio is completely broken on some games, causing massive crackling and distortion where the old HLE audio worked perfectly fine. This is a major issue which is completely breaking the end user experience and making Dolphin unusable!

Asynchronous audio is a feature requested very often in other emulators and it works perfectly fine in PS1 and PS2 emulation, it even is the recommended setting for best quality in most user forums there. This is because 90% of the PCs out there will not be able to always and in every situation play a game at 100% speed resulting in massive audio issues and bug reports once New AX HLE gets part of the stable release. Even if there are small FPS drops for a short time, the audio will sound ugly and distorted since it will not run at a stable speed, which is a huge problem.

I'm just bringing this up early because maybe developers can get creative and find a solution. A simple solution could be to bring back to old HLE as an option, a better one would be to develop a new and optional asynchronous mode to New AX HLE. And Asynchronous audio does not break games since nearly all games run fine with it right now.

I figured I'd drop off my two cents here too: Neither the old or the New AX-HLE are perfect, but the New AX-HLE is far better than the old implementation. Bringing the old and broken stuff back would be pointless and a downgrade.

And even if new-ax-hle had some instances of being worse than the old HLE, at least it can be fixed because it completely matches how Gamecube sound processing works. The opposite is not true.

In theory you are right. But you forget the many end users that just want to play their games with working audio.
Since the new always-100% speed requirement more than doubles the system requirements and is nearly impossible even on todays overclocked high end PS's and due to the fact that time stretched audio just sounds ugly with an unstable frame rate this decision goes in a wrong, higan-like direction, where the end product has major issues and only works in theory.

It should not be too much effort to implement an asynchronous version of the new HLE. Please do not forget the average end user that does not have the power for always 100% emulation speed and will then be forced to turn off audio.

"It should not be too much effort to implement an asynchronous version of the new HLE."

Cool, then stop talking about it until you've got a working patch that conforms to our code quality standards.