Although there are many audio editing tools, many are not for professionals and will require extensive knowledge to use properly.
AudioRetoucher streamlines many processes and allows the user to modify pitch, speed without any effect on one another. It also has a beautiful interface that doesn't require knowledge about music post-production.
The application can also calculate the beats/minute using a Tap Tempo controller, modify equalization settings (through control faders), and amplify the high and low frequencies with the appropriate filters. It is compatible with MP3, WAV, and WMA file formats and allows for the export of processed files to MP3.
AudioRetoucher is an great tool for singers . It can change pitch or calculate speed in real time, which makes life easier.