optional features (Purchase): - free of Ads - manual frequency input - different signals - white/pink noise - note/tone for frequency - Left/right channel, stereo - create a tone sequence for playing several different frequencies in particular time slot - loop for tone sequence - save and delete tone sequences - load saved tone sequences - send your tone sequence as an audio file (.caf format) - option to compress audio files Attention: If you want to share your results with others, first test your audible frequencies, then mark under the speakers your lowest audible tone and your highest audible tone (stored only temporarily). A small hint: the chart will show you what other frequencies of your age are still possible to reach.