I compared all the various DSD->PCM algorithms in the regular foo_input_sacd and then compared what I felt was the best sounding algorithm to this HQ mod and I also found that this HQ mod sounds better.  It's subtle and you need audiophile equipment to hear the difference.

Since the whole point of SACD is these subtle improvements, I'm now using this HQ mod instead of the regular version. So, thanks for posting it here !

By the way, why did you remove the option to add gain digitally ?  Isn't that transparent since it is done in the digital domain ?  Without it, the DSD->PCM output is always lower than other music files.

Echo AudioFire drivers don't support WASAPI

False. I've been using AudioFire2 with WASAPI for years. Echo drivers have excellent WASAPI support.

Echo AudioFire drivers don't support WASAPI

False. I've been using AudioFire2 with WASAPI for years. Echo drivers have excellent WASAPI support.

Just FYI, if you do a web search on WASAPI, you'll see that the "perfect sound forever"-style claims for the theory did not actually correspond to the actual implementation (which, of course, is true for just about everything).
What actually sounds better depends on other specifics of the individual implementation.