Removing Higher Frequencies

Very much a beginner with Audacity, I’m wanting to remove the Irish whistle from an instrumental mp3 to leave me with a “karaoke” backing track that I can play my own whistle against but the standard method doesn’t work because the whistle isn’t central in the mix. Someone suggested that I use a Shelf filter to take out frequencies higher than the bottom note of the whistle but didn’t explain how. I got as far as downloading shelf.ny and installing it in Audacity. Can you tell me how to proceed, step by step? I believe the lowest frequency of the whistle is 349.20. I’m running 2.0.3 on Mac OS X 10.6.

I would also be interested in any other procedures that might work as well or better. Many thanks.

The middle of all the range of frequencies that you can hear is about 400. So removing everything above 349 is essentially removing all sound.

You can try this with the built-in tools. Effect > Hi Pass Filter: 18dB and choose your frequency.

You usually can’t split a performance up into individual instruments. The pitches, overtones and harmonics of each instrument overlap too much, even if the instruments are playing very different notes.


Thanks for your reply. I’m sorry, but I know so little that I don’t understand your post and have no idea what a Hi Pass Filter is. Could you clarify what you mean a little further? Thanks.

A high-pass filter is a filter that allows high frequencies and blocks low frequencies.
A low-pass filter does the opposite - it allows low frequencies and blocks high frequencies.

Audacity has a high-pass filter and a low-pass filter in the “Effect” menu (scroll down below the divider line in the Effect menu).

Actually, Koz got it the wrong way round - to allow frequencies below 400 Hz and cut frequencies above 400 Hz, you would need to use a “Low-Pass” filter.
“Effect menu > Low-Pass Filter”
Try setting the Roll off" to “18” or “24” (dB per octave).
To hear (mostly) sounds below 400 Hz, set the “Cutoff frequency (Hz)” to 400.

As Koz wrote, that will remove most of the music leaving mostly just the bass. Experiment with other frequency settings. I don’t think that the result that you want is possible, but you will soon get an idea of what high-pass and low-pass filters can do.
More about the Low Pass Filter here: Audacity Manual

Thanks for the clarification. I tried the Low Pass Filter but encountered a major problem with clipping pretty much throughout the tune. I don’t know how to remove clipping - perhaps there’s another filter for that. I’m working with a .flac file so I tried Vocal Remover (simple) which didn’t clip and it muted the whistle a little but didn’t produce the effect I would like. Perhaps it’s not possible.

Hi All,

Can someone pls remove the while in this following Karaoke( and send me the mp3 file for the same. I am just a beginner and tried to do it my own but did not get success. My music teacher needs it urgently. Would be highly obliged if someone could help me.

Thanks in advance.