I have had mixed results after the initial firmware from the steam vr beta patch. Some nights it sounds great and is so loud I have to lower the steam vr sound to around 80% to avoid hurting my ears. Other nights, I can max the sound in steam vr, (and headphones button all the way up) and sound does not hurt my ears.
There is definitely something disabling the fix at some point, it somewhat seems like if you boot up or start steam vr w the pro audio selected, it doesn't load properly. If you try switching to hdmi vive pro audio, restart steam vr, or computer even, then switch back pro multimedia audio and double check all volume is set to max, sometimes that gets it working louder again.
It's really hard to pinpoint, but there is definitely still something weird going on, and that's likely why some people are saing it's improved and others are not.
I will try to do some more testng, but really don't have a ton of time to enjoy VR as it is, so I tend to rather play and try to enjoy my Vive Pro, instead of sitting there spending time testing.
Hopefully this helps and we all see a fix soon.