The other reason that material is recorded at 15ips and 30ips in the studio is headroom. Here, when recording live these speeds have an advantage. This however does not translate into making a dub. The dynamics of recording a drum set live is completely different that dubbing a recording of a drum set.Indeed.
...a second generation half track master at 7.5ips will blow the pants off of its vinyl brother...I guess I'd better get my decks lined up for CCIR and NAB @ 7.5 in/s! ;-)