Just to get back to the original post of this thread for a moment.
Does anyone know what source is being used for streaming tracks?
Do record companies allow their master tapes to be used?
The source used depends on the streaming service. Amazon Prime Music uses 256k MP3. Apple iTunes uses ALAC at 44.1. Tidal uses FLAC at 44.1. I believe they are all commercially available tracks, not studio masters.
There may be some hi-res master tracks at 24/96, 24/176.4 or 24/192 available at HDTracks.com for download, depending on the artist. There are master tracks available for download from Bluecoastrecords.com. These are very well recorded with minimal EQ and no compression. If you have a good system, they sound live. Keith Greeninger, Alex DeGrassi and Jane Selkye are some of my favorites. I would start with Bluecoast collection 2.
Steve N.
Empirical Audio