Soundwaves with Music

[Mathew Steel 151]

Today, I've been thinking about something and decided to test it when I came home. I changed the pitch of a song without changing the frequency. The song sounded distorted. But then when I adjusted the tempo too, it sounded a bit less distorted. Why?

 

From my lack of basic knowledge of physics, I know that by increasing the tempo of a song, the length of wavelengths decreases, but the data can't just disappear. So in order to make sure the data isn't lost, something else must change in size. Which I believe would be the amplitude, it would increase in height and so changing the pitch. If these aren't changed in proportion to one another, would they cause the music to sound distorted?

 

I'm sorry if this didn't make total sense, it would be far easier to draw what I am trying to explain but if this is enough to make sense, then any more information would be appreciated. Thank you!

Edited May 4, 2016 by Mathew Steel

[Lord_Chris 251]

Yes, of course. If things aren't changed in similar proportions, then of course they wit would become distorted. But without knowing what you've changed (and to which settings), what the song sounds like and originally sounded like, we won't be able to help much.

[EaglePrince 230]

As far as I get it, changing amplitude should only change the volume (it determines how loud is the music), so I guess that you shouldn't change those two (pitch/frequency and volume) proportionally but to change only one of them. Now, my guess is that these problems like the one you mentioned can be caused by the software "not doing the job right" in combination with the original recording not being perfect. Whenever you do any changes you always lose some data - like in almost any calculation in nature.

 

Now, I was assuming that pitch and frequency are (almost) the same thing, but they are not... "Pitch may be quantified as a frequency, but pitch is not a purely objective physical property; it is a subjective psychoacoustical attribute of sound." - from Wikipedia

 

Another issue is that we may not be able to simplify this matter to only few properties, as sounds are complex - especially music, in which we have several sounds in a same moment (though they are merged into one).

[Lord_Chris 251]

When I've altered the amplitude before if I make something too loud or quiet then it does sound distorted, perhaps that's what has happened here. It only sounds fine still inside a "spectrum" of sorts, if you know what I mean.

[Mathew Steel 151]

Honestly, I don't really want to change it, I was curious to why the distortion was present. I guess it makes sense really.?

 

Eagle, I know that a lot of proper sound editing programs will change pitch and tempo in sync, whereas a lot of video editing programs, allow the changes to be manual. I tested this using Sony Vegas and the distortion was present. Although, I'm sure there is a way to get it to change the pitch and tempo together.

 

Thank you for the replies though everyone! :)