Tempo Controls for Time Stretching
Music Speed Changer Tempo Control lets you adjust an audio track's speed independent of the pitch. This means you can slow down audio without making it sound deeper and speed up audio without making it sound higher.
You can control the playing track's tempo either by using the slider or by tapping on the display value and adjusting the wheel picker. To increase the tempo, ie make the audio play faster, slide the slider to the right or enter a higher number for the tempo value. To slow down the speed of music, slide the tempo slider to the left, or enter a lesser value. This will decrease the speed and slow down the song that is playing.
The default value range is 25% to 250%. The range can be expanded up to 15% to 500% in Settings.
See here for adding plus and minus buttons in the editor
