Bleeper

Create sound effects by drawing volume and pitch sequences, using the 8 waveforms to choose from.
Right-click to remove steps in the sequence. Hold shift to only change the waveform. 
Adjust sound duration (speed), pitch range, or snap pitch to the chromatic scale. 

When you are done editing, exports all your sounds to mp3 or wav audio files. 
Or save your program as text data for future edits.

Shortcuts: 

• space: play current sound
• up arrow: navigate to previous sound in the list
• down arrow: navigate to next sound in the list
• cmd+up arrow: move selected sound up in the list
• cmd+down arrow: move selected sound down in the list
• enter: edit selected sound name
• backspace / delete: delete selected sound
• cmd+z: undo
• shift+cmd+z: redo 
• cmd+c: copy current sound to a new sound
• cmd+s: save program data to a text file (to reload it: drag&drop this file on Bleeper)
• cmd+e: export all sounds to mp3 or wav (a menu will pop up)
• cmd+n: new program (delete all sounds)

Bleeper is the official SFX creation tool for Pixelbox