How can I set the speed of manipulate play button?

Question

Can you set the speed at which a Manipulate plays when the play button is clicked?

Answer 1

AnimationRate is at least one way to do this, and it can be applied on a per-control basis:

Manipulate[x, {x, 0, 10, AnimationRate -> 1/10, Appearance -> "Open"}]

Manipulate[x, {x, 0, 10, AnimationRate -> 10, Appearance -> "Open"}]

Answer 2

I presume you are looking for AnimationRate.
Also, if you want smooth motion you should consider RefreshRate.

Manipulate[
 Plot[Sin[x + a], {x, 0, 5 Pi}],
 {a, 0, 2 Pi, ControlType -> Animator, AnimationRate -> 1, RefreshRate -> 60}
]