I need to make a player control for playback of history of states. The context is not important, it should basically act like in a media player. It is easy to use buttons for most functions, such as: 'play', 'next', 'previous', etc. The only part I am not sure about is the playback speed. This variable should make the simulation run faster, slower, and backwards. A dropdown is my current pick because it limits the user to set unreasonable high values. This is good and all, but it takes away the user's freedom to modify the speed in some form. The simulation could take a long time for example.
My current speed control:
What is a good way to control speed in an user interface, giving the user freedom to modify the value, but also making it easy to use?