I played an acoustic piano for years, long ago. I just purchased my first digital piano to get back into it, a Yamaha P-35. I immediately started playing one of my old favorite songs. It sounds great for the most part, but something sounded off to me. The song has a lot of steps down from F# to F (just above middle C), and I eventually realized that when these two notes are played together there is a weird wobbling/wavering/vibrating sound effect. It sounds like something that could happen with an acoustic device (interference between sound frequencies?) and I know these digital pianos are designed to emulate real acoustics as much as possible, but this vibrating for some reason is really grating on my ears, and I just don't remember ever hearing it before when I played this song on an acoustic piano years ago.

I don't have access to an acoustic piano (or any other piano) right now, so I have no way to figure out if this is normal or not. I've recorded a short audio file which is hosted here. In the recording I hit in series:

  • F# alone
  • F alone
  • F step into F# while continuing to hold both

Listen to the 3rd sound, specifically as it starts to fade out turn the volume up very high and you should here the wobbling I'm talking about. In the recording I don't notice it nearly as much as when I'm playing and have headphones on or using the keyboard's speakers.

Can any experts or acoustic piano owners let me know if this is normal, or some kind of issue?

(I also just noticed that even looking at the pulsing circle graphic on the file host where I uploaded the mp3, the vibrations in the 3rd sound are visible)

1 Answer 1


It sounds like you are noticing the beat frequency, which is completely normal and something you ought to hear on a proper piano as well. A lot of old/upright pianos will have a somewhat muddy sound (compared to the concert grand emulated by most digital pianos) which could make it less noticeable, though. A minor second is quite a dissonant interval so I would think that's the reason it bothers you.

  • Thank you! I wouldn't be surprised if this piano does indeed have better sound than the cheap upright I played growing up. That's probably why I never noticed it before. Other than that one issue I am loving the sound on this! May 15, 2015 at 3:49
  • 1
    You are listening very closely and analytically, with the volume right up. If you did that to an acoustic piano you'd hear all sorts of stuff too!
    – Laurence
    Oct 1, 2017 at 13:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.