Cherry Audio Forums

Hi, I've noticed that the Linear FM in the Cherry Audio oscillator is "broken" since version 2.2.3. It used to work ai it should in version 2.0.30 but now it sounds similar (but not equal) to the Exponential FM. This it true for the Oscillator and Vintage Oscillator, in both the Normal and Poly versions. Can someone at Cherry Audio please verify this and correct the Bug?

Cheers

Project

Hello Project,

Exponential and Linear modulation hasn't changed, and is working perfectly. Here's a video testing the Exponential and Linear modulation features of both the Oscillator module and the Vintage Oscillator module.



https://youtu.be/vkxXGiOxuEQ

Please let us know if you have any questions!

- Dan @ Cherry Audio

I'm sorry, but I think you're wrong. The video is demonstrating FM with a DC signal, I'm talking AC modulation at audio rate. Try to confront the behavior of the actual version of Voltage Modular with one of the old versions or with another VCO that has Linear FM (I have, for example, the Zeroscillator).
The Oscillator response to audio rate FM has changed since version 2.2.3 and now you hear a distinctive change in pitch when you apply Linear FM that you didn't get in the old versions. I made a patch that all of my students made at the same time on their computers (I'm using Voltage Modular for online teaching since last year) and the results were really different between the ones that had upgraded to 2.2.3 and the ones that were using one of the previous versions.
I don't know what happened, but please check it and you'll see, I was really surprised it's been unnoticed for 3 revisions

Cheers

Project

Could you please attach the preset? We'll check it out and see if we can figure out what's changed.

Thanks,

- Dan @ Cherry Audio

Thanks for your reply Dan, I've attached the preset piano strano 2, that's supposed to give you a steady pitch (and that's what it did in the previous VM versions) and that now exhibits this "gliding" effect on the pitch when you play with higher velocities.
The preset Piano Strano OK ZO instead use the zeroscillator as a Carrier and it works as the same patch made with the standard Oscillator used to work in the old VM versions.
I've taken a second look at your demonstration video and it actually demonstrates linear FM working as it should, so I did some tests myself and I think that the strange behavior starts when the FM amount is more than 70% (in your video is 50%) and the control voltage is negative.
What I mean is that pitch is supposed to go lower if you apply a greater negative voltage, instead when the FM amount is more than about 70% you hear the pitch going back up to the original value (at 100% the pitch is equal to the starting value); could this be a symptom of the problem?

Hi Project,

You're absolutely correct, there was a mistake with linear modulation introduced into VM's oscillator algorithm that was not obvious. The DC test posted above is sonically correct, but with audio-rate modulation the issue with linear modulation does make itself heard.

This will be fixed in the next release. However, for now, you can fix it by following these steps:

1) Download voltage.jar file here: https://cherryaudio.com/assets/voltage- ... oltage.jar

2A) If you are on Windows, replace the voltage.jar file in C:\ProgramData\Voltage with this new version.
2B) If you are on Mac, replace the voltage.jar file in /Library/Application\ Support/Voltage with this new version.

3) Restart Voltage Modular, and the linear modulation should be fixed.

Thanks for brining this to our attention! Please confirm that this fixes your issue.

Thanks,
- Dan @ Cherry Audio

Thank you, that was quick! And it fixed the issue!!!

Cheers

Project