Answer to Q#2:
So far, all I know to improve the sound quality on Tidal is to use the WDM driver in JRiver or use Roon, which has a WASAPI out for Windows (and Event Mode in beta at the moment). Fidelify does not work with Tidal, only Spotify.
I thought the Roon output was quite an improvement in sound for Tidal, enough to pony up for the one-year Roon subscription. I never liked JRiver, so while it definitely improved the sound with the WDM driver I hated the interface and never bought a legit JRiver copy. Roon has other benefits too, especially if you're a Tidal user.
https://roonlabs.com/
Listening to Tidal right now I'm a fan and premium subscriber .
FWIW
Note :
Windows Driver Model (WDM) ^^^[ins. referenced above ]— also known at one point as the Win32 Driver Model — is a framework for device drivers that was introduced with Windows 98 and Windows 2000 to replace VxD, which was used on older versions of Windows such as Windows 95 and Windows 3.1, WDM drivers are layered in a complex hierarchy and communicate with each other via I/O request packets -wikipedia -
Modern Windows OS supports WHQL HDWE driver certification and WDDM for Video (WDM) drivers are obsolete in newer Windows OS in-other than a backward compatibility mode and this can be unstable .
Caution
If any given WDM drivers run on a given newer OS configuration at all ,
note : WDM drivers will be in a backwards compatibility mode and I/O instruction set and *may * significantly depreciate overall I/O throughput and *can*cause instability crashes ,application hangs and or BSD or hose your windows install beyond repair other than a clean install and loss of all your file,installed applications and data (like any driver )
FWIW personally I would caution against any application or driver that changes HDWE driver configuration other than reputable well documented products *well* beyond beta due to the aforementioned cautions
OTOH *I don't think* J river ever *really got out of beta *
Take it or leave it from here as you will ...
I'm Not here argue or prove a point. I Won't Respond to (other than a legitimate question *if I can answer it ) I already have an in depth understanding of what I Posted here .
Windows 8.1 and Windows 10 beta and windows 7 to a lesser extent with some tweaking and modified drivers ( note sig below ) supports properly configured WASPI drivers and thus off loading audio stack CPU wait states ,CPU audio processing and utilizing the DSP more efficiently in addition to WASPI configured USB /MIDI HDWE thus no need for third party .exe beyond a Web Browser (with Tidal or any ISP steam supported by a web browser)that :
outside of any undesirable DSP, zones on 2 ch (volume leveling i.e compression limiting adding thd+n reducing dynamic range by raising the noise floor to do this ), convolution, etc. compression for playback gain, again i.e compression and *excessive additive EQ * do little more than muddy the sound IMO and absolutely create additional running processes ,CPU cycles ,latencies ,slower I/O performance etc. this kind of stuff been has and can be all measured (see below )
IOW nothing has changed recently with digital discrete time signal sampling and signal reconstruction within a limited bandwidth or digital transmission and nothing is new about that in J river . OTOH try if you like it but be aware of the mentioned cautions .
I have professional sound editors and VST's thay can do all that and tons more but what we find at 16/44 in the business a *little conservative EQ *isn't bad on occasion
anything beyond that at 16/44 raises the noise floor ,reduces dynamic range and produces thd+n (audible distortion ) that's why we never mix at 16/44 or up sample at any time .
Note: you can often basic EQ within widows with many installed sound device exe. also many folks prefer a little playback gain that's a common result of third party exe software which can include driver exe.
Again if you want to try the J river Windows drivers and or media player that's certainly within your prerogatives and if prefer what they can do that's fine with me but again be aware of the mentioned cautions .
Be aware ANY driver, [ins. also application] can have compatibility issues in Windows even WHQL signed drivers on any given configuration and hose your Windows installation requiring a clean install and loss of all your data and media files on your primary drive partition . With regards to WHQL certified drivers or any drivers . Trust me nobody can test all the variables and configurations in the field ( note my sig )