I think B was recorded later in the day and the sun had gone down a bit, thus making it sound a tiny bit darker, thereby obviously making B the rosewood fretboard!
Actually, both sounded pretty much the same to me on my headphones.
Next tests: Ebony vs Ebonol...
20 vs 21 vs 24 fret necks
vintage frets vs modern jumbo frets
left handed necks vs right handed
Energizer vs Duracell effect on tone
Colored ball ends vs plain
Angled plug vs straight (that 90 degree turn sucks the tone right out of my bass!)
Actually, both sounded pretty much the same to me on my headphones.
Next tests: Ebony vs Ebonol...
20 vs 21 vs 24 fret necks
vintage frets vs modern jumbo frets
left handed necks vs right handed
Energizer vs Duracell effect on tone
Colored ball ends vs plain
Angled plug vs straight (that 90 degree turn sucks the tone right out of my bass!)