It is a high performance tuning fork program.It can generate 4 octave sound select by name.The movement of the octave : in a triangular sign. The movement of the semitone : with # and ♭. The output selection of a continuous sound, continual sound, and the single sound can be done. (toggle)
Concert Pitch - 440 Hz adjustableNo add.
Sound output and the quality of the program depends strongly on the device. (especially on low freqency) it is not my fault.
Speaker of Smart phone can not output sounds under 200Hz (around A sound) . Your can test your device on free version.
the external speaker may improve characteristics.