Have a play button & a playback rate feature

User can push a button to play sound + would be nice to have a shortcut key mapped to "play". (maybe "p")?
Then, user should be allowed to modify the playback speed, slowing the sound down or speeding it up. Some ideas- Raven uses a user entered field where decimal values slow down the sound, positive numbers speed up the sound. Pamguard has a slider bar. Whatever is easiest to code