The Siemens IC has a harsh-sounding square-wave output which can be filtered a little with a capacitor. They recommend installing the speaker in a horn or tube to make the sound more filtered so that it is more pleasant.
A good sounding mechanical ding dong doorbell makes smooth sine-waves.
With this ic with little speaker or piezo you can hear very clearly ding dong or 3 different tones. I mean sound not bad. But if you find less then u can use tr amplifier.
Same question for me also until now I Didn't find a good door bell (Sound Ding Dong)all are having musical door bells.The guest must use a long press to hear the music.....Its not practical.