Looking at the R2R playing, about 1/2 way through on a 7' reel
7.5 IPS it looks like the reel speed is 30 RPM. :)
Off hand I think the -3DB is 18 Khz for 7 1/2' and 20 Khz for 15 ips,
but your R2R manual should give the details.
Listening to a Decca tape - enhanced for stereotape ( no year )
Golden Favorites - The Orginal Ink Spots, with a New Amp/Pre-amp
and they sound really good. I think I would have a less fidelity, or mono recording with good sound, that poor CD copy of a better known pressing.
I am finding about 3% of CD's just don't make the grade for quality they could have.
Ben.