Half speed takes 25 presses to reach #742

Since #701 the slow speed can be set anywhere from 0.50x to 0.99x, by scrolling over the slow button or with the arrow keys. Getting to half speed, the slowest and a common practice speed, takes 25 scroll notches or key presses, and the slow speed then stays at 0.50x until it is moved back.

Half speed should be one press away, like 1x, without giving up the slow speed the player has set.