Pitch changes on imported low frequency sound

I’ve imported a 4 Hz tone into Audacity and before I do anything with it it seems to sound like it’s a higher pitch and a much coarser sound (I’m afraid I’m no music expert so this is a layman’s interpretation of the changes).

How do I stop it doing this?


4 Hz is inaudible (http://en.wikipedia.org/wiki/Hearing#Frequency_range). If you can hear something it is probably your speakers / headphones rattling.

Maybe 4kHz (4000Hz)??? EDIT - I guess 4kHz isn’t exactly “low frequency”, but you said it “sounds like a higher pitch” and you can’t hear 4Hz.

Audacity won’t “accidently” change the pitch/frequency. It’s just digital data… However, if the clock in your soundcard is off, the frequency can be off when you play back (or when you record). But unless you have perfect pitch or you have a tone to compare to, it’s usually not enough to notice. If your soundcard clock is off, the pitch will also be off in Windows Media Player.

it seems to sound like it’s a higher pitch and a much coarser sound

What’s the format? What’s the volume level look like? Is there any [u]clipping[/u]?*

Some formats can go over 0dBFS, and some formats will clip (distort) if you try to go over 0dB. Although clipping won’t change the perceived pitch** it does add higher-frequency harmonics and it can sound course, or harsh. Your analog-to-digital and your digital-to-analog converter are also limited to 0dBFS.


  • Go to View and select Show Clipping. If there’s clipping, you’ll see red markers in the waveform display.

    ** You’ll hear the same musical note, and if one instrument is clipped it won’t sound out-of-tune with the other instruments.