frequency elimination/dampening using nyquist

Programming and Development Nyquist
1

Hi,

I’ve done some research in the archives and it seems that nyquist is probably best for what I want to accomplish. I am looking to cut out the dominating effect of some cymbals in a song that is detracting from the rest of the instruments. In a perfect world I would love to get ahold of the original tracks before being mixed to the master but seeing how that’s not possible…

I guess I’m looking for the equivalent of a low-pass/high-pass combination effect. I have tried the 31-band EQ which has helped eliminate the cymbals, but I want to get even more specific as to what EXACT frequency to eliminate/dampen (ones that don’t show up on the EQ) OR a range of frequencies (between X and Y).

How can I write a script for eliminating or dampening an exact frequency
and a range of frequencies using nyquist?

thanks

2

Have a look at this “band stop” filter https://forum.audacityteam.org/t/bandstop-plug-in/18400/1

3

thanks for that, but it only goes up to 10KHz? When I was messing around with the EQ, 12.5Khz seemed to be where the key frequencies were…

4

Maybe use the cymbal noise (on its own) as the “noise profile” for “noise reduction”.

don’t get your hopes up though , the result may be too distorted.

5

To increase the maximum frequency for the plug-in, open the .ny file in a text editor and find the line:

;control freq "Centre Frequency" real "[Hz]" 1000 100 10000

and change it to

;control freq "Centre Frequency" real "[Hz]" 1000 100 15000

For very high frequency filtering the audio must be at a high sample rate.

6

The “quick & dirty” solution would be to type the frequency value with the keyboard into the small text window beside the slider. As far as I can see from the code, the plugin works with frequencies up to samplefrequency/2, the 10kHz is only an artificial limitation of the slider range. Just tested with 15000Hz, it works.

7

If the centre frequency plus half the stop-band width is too high (greater than half the sample frequency) it will give an error message.
For a band with of 0.5 octaves you can go up to about 18.5 kHz centre frequency (assuming a sample rate of 44.1 kHz)

8

It worked! I haven’t used it on the aforementioned project, which I plan on doing when I get back to work on monday. However, I input the 15000 in the text editor and it came out perfect, no problems. thank you!