The pitch scope app measures sound from the microphone and displays its pitch(frequency), waveform, and spectrum in real time. Use this app to analyze voices and instrument sounds.

Why do vowels U O A E I sound like U O A E I? You can see and check the waveform and spectrum of each vowel. 
When you hear someone says “this guitar sounds brightly and that one sounds heavy”, what is the difference? For such a question, you can check it with this app.