How to Notch above 10,000MH

[Papasmithnc]

Hello,

I have tinnitus and have heard about this treatment called notch therapy where the frequency of your tinnitus is removed from a sound file. You then listen to this and it is supposed to lessen the intensity of your tinnitus.

My tinnitus frequency seems to be around 11,200mh. I need to notch out 1/2 octave below and above. Any solutions?

Windows 7 - 64bit. Audacity version 2.0.2.

Thanks,
Dave in NC, USA

[kozikowski]

That's not a notch filter any more. That's adroit handling of the regular filters.

Duplicate the track so you have two copies. On the top copy, Effect > Low Pass Filter > whatever the low number is, and on the second track, Effect > High Pass Filter > whatever the high number is. When you export the track, it will mix down to one track and be missing everything between your two values.

You may need to amplify -6dB to keep from overloading.

Note how I'm making you do the math.

There may be a way to do this with the Nyquist tools. I'm not sure.

Koz

[steve]

My tinnitus frequency seems to be around 11,200mh.

I presume that you mean 11200 Hz.

The effect that you need is called a "band stop filter".
See this topic: http://forum.audacityteam.org/viewtopic ... 46&t=69513

[Papasmithnc]

Thanks for the replies.

The Band Stop Filter goes up to 10,000 as the center point of the frequency that is being removed. You can certainly make the width of the band wide enough to center on the 11200 Hz. However, because the band taken out is so wide, the quality of the sound file, in addition to the effectiveness of the technique, are degraded. I'll try the other technique give here but, a lot of tinnitus sufferers have frequencies well above 10,000 Hz. It would be really nice if someone would increase the upper range of the Band Stop filter.

For anyone interested, I am using white noise to create a notched audio file which I have read is more effective than using traditional music files. It has a wide and level frequency range up to 16000 Hz and higher according to the spectrum analyzer in Audacity. White noise, (depending on the white noise file) provides a lot more audio input to the brain above and below your tinnitus frequency than a normal music file. This provides more of the right audio input that encourages the brain to create the new neural connections neccessary for this method to work. That is what I understand anyway.

If anyone has any other methods to create the sound file that I need, I would greatly appreciate it. In any event, thanks to the Audacity creaters for this great program.

[steve]

The Band Stop Filter goes up to 10,000 as the center point of the frequency that is being removed.

That is an "artificial" limit set by the slider scale,
The reason for that limit is that the highest frequency possible for CD quality sound is a little over 20 kHz (20000 Hz) which is 1 octave above 10000 Hz.

If you want to remove a narrow band, set the "Stop Band Width" first, then type in 11200 as centre frequency (rather than using the slider).
Use "Plot Spectrum" to check the results.

If you find this useful and you can tell me exactly the frequency and stop band width that you want, I can post a custom version of the plug-in to suit.

[Papasmithnc]

The Band Stop Filter goes up to 10,000 as the center point of the frequency that is being removed.

That is an "artificial" limit set by the slider scale,
The reason for that limit is that the highest frequency possible for CD quality sound is a little over 20 kHz (20000 Hz) which is 1 octave above 10000 Hz.

If you want to remove a narrow band, set the "Stop Band Width" first, then type in 11200 as centre frequency (rather than using the slider).
Use "Plot Spectrum" to check the results.

If you find this useful and you can tell me exactly the frequency and stop band width that you want, I can post a custom version of the plug-in to suit.

Thanks Steve.

I checked on what you said and, sure enough, I can go beyond the slider scale. I used the Plot Spectrum tool and it looks perfect.

I appreciate your help. It is great to have resources like you and others here on this forum.

[crowwoods1]

Hi Papasmithnc,
What did you set your 'stop band width' to be? I'm notching for 10404 Hz and played with the stop band width, but I still get it to work.

[crowwoods1]

I just figured out that I can notch above 10,000 Hz with Notch Filter. I used the default Q=1.0 with the frequency of 10404 Hz. Is that OK?

[Gale Andrews]

Note that in current Audacity (2.1.2) the plugin input is validated according to the parameter boundaries set in the plugin. Center frequencies above 10000 Hz will thus be rejected, and you would have to use a text editor to modify the line starting with ;control freq "Center Frequency" to ;control freq "Center Frequency" real "[Hz]" 1000 100 11000 or similar.


Gale

[Trebor]

... I used the default Q=1.0 with the frequency of 10404 Hz. Is that OK?

Q=1 is a wide notch ...

Notch 11111Hz, q=1 versus q=11.gif (33.8 KiB) Viewed 858 times