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AvoidNF8 · Posted - Thu May 03, 2001 11:11 pm

OK I have looked through the help files and manual and cant find the answer to this one. I have a tone in the middle of a song. Its in the left side only. I can see it in the spectral view. It appears to range between 400 and 600Hz and only lasts for about 8 seconds. The problem is that there is no clean section that has this tone in it so I cant sample it from anywhere. Before I just started playing with it I thought I might ask for any tips.

mjb · Posted - Fri May 04, 2001 2:49 am

To remove the tone, use the FFT filter transformation. You can probably get a better idea of what the tone's frequency is by highlighting the section where the tone is, and then going to "Analyse: Frequency Analysis". Look for a peak around the 400-600 Hz mark, and hover the cursor on it. At the bottom of the window, you can see the frequency you are pointing at.

Then go into FFT filter, and make a Passive filter, that is "Flat" at 100% (i.e. don't touch the sound), and then draw a notch in it as narrowly as you can, and as deep (towards 0%) as possible, around the target frequency. Use Preview to see if the tone has gone away, and make sure not to damage too much audio!

Take a look at the Preset for 60Hz notch to get an idea of what the shape should be, you'll need to move the Notch over to the right for your tone ...
Mike.

Edited by - mjb on 05/04/2001 02:54:41 AM

Detlev Dalitz · Posted - Fri May 04, 2001 3:22 am

Additional advice to mjb's instructions:
In dialog "Settings/Spectral"
- tweak "Resolution" to 1024 or more
- tweak "Window Width" to 50% or less.
to get more detailed spectral view in the specific area.

Oh, just in this moment there comes up an idea:
It were great, if CEP would have a graphical tool to manipulate frequencies in the way (like painting software does have), to smudge or "lighten" (attenuate) or "contrast" (amplify) those frequency area by rubbing over it with a mouse cep-brush.
To limit the affected area there should be the possibility to drag windows around the working area.
Get the idea?

DD.20010504.1217

dubbah2000 · Posted - Fri May 04, 2001 4:55 am

I had a like wise problem with my first soundcard, way back, a Turtle Beach Monterey. I paid $500 for it and yes it had a 1khz distortion on the left channel. Man, was I frustrated with that situation! Because of the bad connection between Turtle Beach and my small town dealer in the Netherlands I eventually decided to make a preset in Cool Edit 1.50 and erase the sound in the end process.

In short: this may very well be your soundcard...

Edited by - dubbah2000 on 05/04/2001 04:56:23 AM

Syntrillium M.D. · Location: USA

Hi all. The Notch Filter is also a great way to eliminate tones, with very narrow bandwidths (so as not to affect adjacent frequencies). Simply go into the Filters>Notch FIlter menu. Click on the first 'frequency' checkbox to activate it. Disable the 'preset level of attenuation' box so that you can enter your own (usually 36-45 dB works great) Dial in your frequency, set the bandwidth (very narrow or super narrow for real tight spots) and preview. You can listen and change the frequency until it's eliminated. Once done, click OK to process.

---Syntrillium Support