This thread proved kind of useful for me.
After reading that I tried disabling just the HP Tone part of the IDT driver. This apparently "provides support for Beats Bass Boost switching for HP ENVY Products".
It seems to have partly solved the issue for me. I don't lose bass or get distortion anymore. Although it does seem to have made my laptop speakers weaker, which is still annoying. But works fine if plugging external speakers into the headphone jack.
It's quite simple to do, you just copy the below into notepad and save it as a ".reg" file. You will probably need to put double question marks around the filename to stop it from saving as a .txt
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\IDT\Apo\GFX\LineOut\plugins\HPTone]
"Load"=dword:00000000
Then click the file after it has saved. It will ask you to confirm changing the registry. Then reboot and it should take affect.
If you ever want to turn it back on, just do the same but change the last 0 to a 1.
The other way you can do this is through regedit and find it through the tree, if you prefer doing it that way. Sorry I know many of you probably know this.
Obviously you change the registry at your own risk. But, this is just a small change and the way I ended up seeing it is that you are disabling something that seems faulty.
HP please let us know if you are aware of this problem and when it might be fixed, to get the driver working properly!?
The driver I'm current using is 6.10.6433.0, which the HP support assistant tells me is up-to-date. Doesn't seem like HP have made a new one since this Nov 12 issue. Could be wrong?