Effect High pass filter with Q

Failed to overinstall defaults (cutoff frequency and q), after attempt to chahge the values error message appears or the effect doesn’t work. The view of document:

;nyquist plug-in;version 1;type process;name “High Pass Filter with Q…”;action “Applying High Pass Filter with Q…”;info “High Pass Filter with Q by David R. Sky”;control freq “Cutoff frequency” real “Hz” 1000 20 10000;control q “Filter q (resonance)” real “q” 1.00 0.00 5.00;; Highpass with Q, works on mono and stereo audio(if (arrayp s)(vector (highpass2 (aref s 0) freq q)(highpass2 (aref s 1) freq q))(highpass2 s freq q))

such as for High (or Low) Pass Filter, here it is easy to set new values. Other view of the document:

;nyquist plug-in
;version 3
;type process
;preview enabled
;categories "http://lv2plug.in/ns/lv2core#LowpassPlugin"
;name "Low Pass Filter..."
;action "Performing Low Pass Filter..."
;author "Dominic Mazzoni"
;copyright "Released under terms of the GNU General Public License version 2"

;; lowpass.ny by Dominic Mazzoni
;; Modified by David R. Sky
;; Updated by Steve Daulton June 2012
;; Released under terms of the GNU General Public License version 2:
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html .

;; To enable the Q control, remove one semicolon from the start of lines 18 and 32

;control rolloff "Rolloff (dB per octave)" choice "  6 dB,12 dB,24 dB,36 dB,48 dB" 1
;;control q "Filter quality (Q) for 12 dB rolloff" real "" 0.7071 .1 20
;control frequency "Cutoff frequency (Hz)" real "" 16000 1 20000

(cond 
  ((> frequency (/ *sound-srate* 2))
    (format nil 
           "Cutoff frequency is set at ~a Hz but must not~%~
           be greater than ~a Hz (half of the track sample rate)."
           frequency
           (truncate (/ *sound-srate* 2.0))))
  ((< frequency 1)
    (format nil
           "Cutoff frequency is set at ~a Hz~%but must be at least 1 Hz."
           frequency))
; ((= rolloff 1)(lowpass2 s frequency (max (min q 20) 0.1)))
  (T 
    (funcall 
      (nth rolloff '(lp lowpass2 lowpass4 lowpass6 lowpass8))
      s frequency)))

Please, correct!

So does this problem happen with Missing features - Audacity Support but not the High Pass or Low Pass?

I tried running Windows is Russian in today’s build on Windows but did not see a problem. Please give an example of Cutoff and q values that cause the problem and give us the Debug output.

Are you inputting Cutoff values above half the sample rate? That gives a specific error in High Pass and Low Pass, but only a generic error in High Pass with Q.


Gale

If you want to enable the Q setting, this is the code that you need:

;nyquist plug-in
;version 3
;type process
;preview enabled
;categories "http://lv2plug.in/ns/lv2core#LowpassPlugin"
;name "Low Pass Filter..."
;action "Performing Low Pass Filter..."
;author "Dominic Mazzoni"
;copyright "Released under terms of the GNU General Public License version 2"

;; lowpass.ny by Dominic Mazzoni
;; Modified by David R. Sky
;; Updated by Steve Daulton June 2012
;; Released under terms of the GNU General Public License version 2:
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html .

;; To enable the Q control, remove one semicolon from the start of lines 18 and 32

;control rolloff "Rolloff (dB per octave)" choice "  6 dB,12 dB,24 dB,36 dB,48 dB" 1
;control q "Filter quality (Q) for 12 dB rolloff" real "" 0.7071 .1 20
;control frequency "Cutoff frequency (Hz)" real "" 16000 1 20000

(cond
  ((> frequency (/ *sound-srate* 2))
    (format nil
           "Cutoff frequency is set at ~a Hz but must not~%~
           be greater than ~a Hz (half of the track sample rate)."
           frequency
           (truncate (/ *sound-srate* 2.0))))
  ((< frequency 1)
    (format nil
           "Cutoff frequency is set at ~a Hz~%but must be at least 1 Hz."
           frequency))
 ((= rolloff 1)(lowpass2 s frequency (max (min q 20) 0.1)))
  (T
    (funcall
      (nth rolloff '(lp lowpass2 lowpass4 lowpass6 lowpass8))
      s frequency)))

I note that in the code comment, the line that says:

;; To enable the Q control, remove one semicolon from the start of lines 18 and 32

it should actually say;

;; To enable the Q control, remove one semicolon from the start of lines 20 and 34

I shall correct that for the next Audacity release.

Did we decide not to make a note about that in the Manual pages for High Pass and Low Pass? I guess the problem may be explaining what Q does or why you might want to enable it.


Gale

I think we decided not to mention it. Normally users will get best results with Q set to 1/2(2^0.5) (0.7071…). In those rare cases where users may want to use other Q settings, they will almost certainly know what “Q” is. We also agreed to retain “High Pass Filter with q” as an optional download (on the wiki).

  1. Download additional plugin High pass filter with Q.
  2. Try to set new value q: 0.88 instead of default 1., save changes in document.
  3. Open audacity, Import file, try to apply the effect, but appears:

Copy from Show log.

21:54:47: Audacity 2.1.0-alpha-Dec 26 2014
21:54:47: Trying to load FFmpeg libraries…
21:54:47: Trying to load FFmpeg libraries from system paths. File name is ‘avformat-55.dll’.
21:54:47: Looking up PATH environment variable…
21:54:47: PATH = ‘C:Windowssystem32;C:Windows;C:WindowsSystem32Wbem;C:WindowsSystem32WindowsPowerShellv1.0’
21:54:47: Checking that ‘’ is in PATH…
21:54:47: FFmpeg directory is in PATH.
21:54:47: Checking for monolithic avformat from ‘avformat-55.dll’.
21:54:47: Error: Failed to load shared library ‘avformat-55.dll’ (error 126: не найден указанный модуль.)
21:54:47: Loading avutil from ‘’.
21:54:47: Error: Failed to load shared library ‘.dll’ (error 126: не найден указанный модуль.)
21:54:47: Loading avcodec from ‘’.
21:54:47: Error: Failed to load shared library ‘.dll’ (error 126: не найден указанный модуль.)
21:54:47: Loading avformat from ‘avformat-55.dll’.
21:54:47: Error: Failed to load shared library ‘avformat-55.dll’ (error 126: не найден указанный модуль.)
21:54:47: Error: Failed to load FFmpeg libraries.
21:54:47: Error: Failed to find compatible FFmpeg libraries.
пост2.png

Attemt to change.
This problem not with High pass filter or Low pass filter, only for filters with q.
пост3.png

Is “High Pass Filter with Q…” listed once in the list of effects, or twice?

Your editor is messing up the lines.
It should look like this:

;nyquist plug-in
;version 1
;type process
;name "High Pass Filter with Q..."
;action "Applying High Pass Filter with Q..."
;info "High Pass Filter with Q by David R. Sky"

;control freq "Cutoff frequency" real "Hz" 1000 20 10000
;control q "Filter q (resonance)" real "q" 1.00 0.00 5.00

;; Highpass with Q, works on mono and stereo audio

(if (arrayp s)
(vector (highpass2 (aref s 0) freq q)
(highpass2 (aref s 1) freq q))

(highpass2 s freq q))

In my editor it looks:

;nyquist plug-in;version 1;type process;name “High Pass Filter with Q…”
;action “Applying High Pass Filter with Q…”
;info “High Pass Filter with Q by David R. Sky”
;control freq “Cutoff frequency” real “Hz” 1000 20 10000
;control q “Filter q (resonance)” real “q” 0.88 0.00 5.00
;; Highpass with Q, works on mono and stereo audio(if (arrayp s)(vector (highpass2 (aref s 0) freq q)(highpass2 (aref s 1) freq q))(highpass2 s freq q))


It is listed once in the effects. I ask to correct problem with setting default values for the additional effect “High pass filter with q”, not to enable q for usual effect High pass filter.

;nyquist plug-in

;version 1

;type process

;name "High Pass Filter with Q..."

;action "Applying High Pass Filter with Q..."

;info "High Pass Filter with Q by David R. Sky"
\
\
\
;control freq "Cutoff frequency" real "Hz" 50 20 10000

;control q "Filter q (resonance)" real "q" 1.00 0.00 5.00
\
\
\
;; Highpass with Q, works on mono and stereo audio
\
\
\
(if (arrayp s)

(vector (highpass2 (aref s 0) freq q)

(highpass2 (aref s 1) freq q))
\
\
\
(highpass2 s freq q))
\
\

By the way, why the button “code” doesn’t work?

Your editor is not reading the “new lines”.

It is important that new lines are retained in the edited file and that the format remains as “plain text”.
I don’t use Windows, but when I did, I used “Notpad++” which is a very good (free) plain text editor: http://notepad-plus-plus.org/

Thank you very much, the document has been edited successfully, the effect with new values works! Explain, please, how to use the button “code”, my attempts failed.

;nyquist plug-in

;version 1

;type process

;name "High Pass Filter with Q..."

;action "Applying High Pass Filter with Q..."

;info "High Pass Filter with Q by David R. Sky"



;control freq "Cutoff frequency" real "Hz" 50 20 10000

;control q "Filter q (resonance)" real "q" 1.00 0.00 5.00



;; Highpass with Q, works on mono and stereo audio



(if (arrayp s)

(vector (highpass2 (aref s 0) freq q)

(highpass2 (aref s 1) freq q))



(highpass2 s freq q))

That’s OK. There are now double line breaks instead of none, but that should work OK.
The author, David R Sky, was blind (sadly he died a few years ago). Many of his plugins have double line spacing, but that should do no harm.

To use “Code” tags, ensure that there is one
[code] tag at the start of the code and one [/code] closing tag at the end.
Your recent posts had:

[code]

[/code] at the start and

[code]

[/code] at the end (which does not work).
Also, ensure that the “Disable BBCode” below the message composing box is not selected.

...

Thank you! “Disable BB code” - default the tick is situated, after taking it away the button has been set to rights.