To speed up audio, adjust the playback rate to the setting you prefer. You can also keep or change the pitch and tempo of the audio as you prefer. It lets you preview the changes you made before conversion. It also supports batch processing so you can speed up several audio files simultaneously.How do you slow down MP3?
For slowing down an MP3 audio, you only need to take several clicks. Firstly, download, install and launch the software on the desktop. Secondly, click plus sign shaped icon to add the MP3s that you want to slow down. Thirdly, drag the tempo bar to change the MP3 speed as you required.