Isochronic Modulator Plug-in

Current download on Wiki Download Nyquist Plug-ins page:

In response to these posts:

The easiest solution would be to modify the tremolo code so that the pulses fade in/out.

I’ve modified the Variable Tremolo effect so that the pulses are adjustable.
To save space in the interface and simplify the code I have taken out the other waveform options.

The “Pulse Width” control allows you to set how long each pulse will be. Higher values will make the sound “on” for longer. Lower values for shorter pulses. At 50% the sound will be on for 50% of the time.

The “Fade Time” control may be increased for a more gradual fade in/out of the pulses. At 0% there will be no fade. At 100% the fade in/out times will be half of the pulse width.

If you want to change the default values, open the isomod.ny file in a text editor and change the numbers shown below, then save.

;control pw “Pulse Width [50%=Square]” real “%” 40 0 100
;control ft “Fade Time” real “%” 15 0 100
;control startf “Initial Modulation Frequency” real “Hz” 7 1 20
;control endf “Final Modulation Frequency” real “Hz” 2 1 20
;control starta “Initial Modulation Depth” int “%” 100 0 100
;control enda “Final Modulation Depth” int “%” 100 0 100

I’ve renamed this plug-in “IsoMod…” (Isochronic Modulator).

This version is also compatible with Audacity 1.2.6

you’ve simplified my life a lot. Thanks.

You’re welcome. It was an interesting project.

Steve, you are awesome! This will be a time-saver indeed (and will help overcome numerous of Audacities editing flaws/imperfections). I’ve been doing this the hard way till now, which doesn’t support isochronic ramping anyway… something I really wanted. But luckily you’ve saved the day (after I decided to Google ‘Audacity isochronic plugin’) …and what damned good timing too! I had just thought about learning how to make plugins just to do this, but that’s not something I really have time for anyway.

So from the bottom of my heart, thanks a million! I registered just to say that, too… :wink:


You’re welcome. Thanks for the feedback.


I’m a bit of a novice. I downloaded the attachment but have no idea how to open it within Audacity so that I can use the plug-in.

Mind giving me a quick tutorial?


Plug-In Installation

To install new plug-ins, place them in the Plug-Ins folder inside the Audacity installation folder. On Windows computers, this is usually under “Program Files”. On Mac OS X, it is usually under “Applications”. Restart Audacity, then the Plug-ins will appear underneath the divider in the “Effect”, “Generate” or “Analyze” menus.

Does this plugin work for the latest beta version for windows 7? I downloaded the plugin it and placed it into the plugins folder but I do not see it show up in any menu.


Yes the plug-in works with Audacity 1.3.12 on all platforms.
Where exactly did yo put the isomod.ny file?
Did you restart Audacity?

I placed it here:

And I did restart Audacity.


Did you previously install Audacity 1.2.6?
I think you’ve put it into an Audacity 1.2 plug-in folder.

Look to see if you have another Audacity folder.
The usual location of the Audacity 1.3 plug-in folder on Windows is:

C:Program FilesAudacity 1.3 Beta (Unicode)Plug-Ins

I haven’t installed it before. I did however just install audacity on my home computer and the mod shows up.

I will reinstall it tomorrow at work and see what happens.

I reinstalled everything and it works properly now.



You’re welcome.

Thank you! Thank you! THANK YOU!!!

I too registered for this forum to thank you. I was doing it the hard way as well and boggling my mind with the math necessary to create a smooth ramp. It gives me giggles how easy your plugin works.

Prayer answered–thanks steve!

I plan on using this for PEMF (Pulsed Electromagnetic Field) waveform generation as well. Would it be possible to modify the code to allow other modulation waveforms? (Especially sine and triangle waves.) Since you’ve already earned your saint-hood maybe you could point me in the direction of a good plug-in programming tutorial?

Yes it would. If you search through this topic and topics linked to it I think there may even be a version that has alternative modulation waveforms.

See here:

There’s some code in this post that creates different modulation waveforms:
It’s not a full plug-in, it’s just a snip of code for creating the modulation waves. You will need some understanding of Nyquist/XLisp to be able to integrate that into the plug-in.

Hi Steve,

Am new on here. Just saw this an wondered what the name of the modulator is to look out for under generate, effect or analyze. I’ve downlaoded the beta 1.3.13 version.



The name of the effect (in the first post of this topic) is “IsoMod…”
It will appear in the “Effect” menu (below the “line”).

I’ve added isomod.ny to Nyquist Effect Plug-ins and corrected a typo in the ;info line.

I also added David Sky’s Ring Modulator and Linear Flanger (and uploaded the missing Panning (Random)), but I forgot to convert those .ny files from David’s upper case to lower case. Is that still a problem on Linux/Mac? If so I’ll have to change that.