things like tape damage and edits become much more noticeable as they
basically take twice the amount of time to pass over the tape head.
These things can "stick out" on playback whereas they wouldn’t on a
conventionally mastered LP.
On the other edge of the sword, and this is a pretty sharp edge, you have to apply only half
the RIAA curve when cutting the lacquer, and that’s not always easy to
do. Plus, now your response for 20-20K has to go down to 10 Hz. "
"""" I would add that half-speed mastering was invented for RCA’s CD4
Quadradisc LP pressings in the early 1970s, when they had to figure out a
way to get the 30kHz subcarrier frequency into the grooves. By reducing
the cutting speed in half, they could easily get 15kHz in there with no
problem.
The above statements are all false:
A tape edit will sound the same either way. Whoever wrote that comment had no experience and had not even thought through the process...
The RIAA pre-emphasis has to be added whether half speed or not.
You can cut 30KHz to a lacquer at normal speed no worries with any cutter system made in the stereo era.
Decca originally developed the half-speed process to help deal with a resonance in their cutterheads. By going half speed, the resonance was shifted upwards one octave (to about 16KHz) where it was less tricky to deal with. This was a decade prior to 4-channel. So most early Londons and Deccas are half-speed mastered.
