Hey thanks for the reply!
I had done the uninstall with "Remove device drivers" option before, but I tried it your way (offline, uninstall+remove then reboot, repeat until the Realtek sound device stops showing Realtek drivers). It took a while, kept coming back with various driver versions - 8216, 8216, 8555, 8555... and then in the end there was no Realtek device listed, and Intel High Definition Audio was listed under Other devices with the warning triangle - said there was no device driver installed.
Then I reinstalled 8555, restarted, and it's the same as before - MaxxAudio is there, sounds like it's active - not enough on speakers (too thin, hard to hear people talking) but too much on my earbuds. I'm used to the sound profile and the bass is decent on them, so it's obvious it's being boosted by the EQ. The panel controls don't seem to do anything at all, so I can't adjust it or turn it off
I'm not using any other audio software, not on the output anyway - I have Steam s*treaming enabled (why is that censored??), so there are two audio devices listed: Steam S*treaming Microphone and Steam S*treaming Speakers, which are used to route the audio from games running in Steam to another device. I guess it's possible that could be interfering, but I never had an issue with it before these last two Realtek updates.
I do use Chrome, yeah - it's not just happening to sound from that program though, if that's what you mean. Even the test audio in MaxxAudio does it. Nothing's changed about my system, just the driver update, and going back to 8216 works every time (until it reinstalls itself, it's really aggressive about that apparently )
And yeah just the one headset (it's just a basic set of wired earbuds, no inline controls or anything like that) but like I said I'm familiar with their sound, and if I crank the EQ and then turn off MaxxAudio there should be some change in the sound! I like bass but this is too much, it just drowns everything else out