Like the title says.
I realize now the removal of the activation sound option was a deliberate choice (apparently, as told by earlier replies here), and I likewise know I'm by far not the only one who finds this to be an issue.
Not being able to disable the activation sound (among other things) makes using Voicemod for content creation and live performances utterly useless. The activation sound is LOUD and, as a result, obnoxious, especially when you need to toggle between effects and voices repeatedly. It breaks the illusion. You might as well replace the activation sound with an obvious, "VOICE CHANGER ON, VOICE CHANGER OFF" soundbite at that rate. That's what most people recognize the sound as anyway.
I would downgrade to V2 but that version doesn't work at all anymore.
If this really is a permanent change, I'll likely be seeking a refund / ending my subscription. This isn't a threat, this is just me plainly stating that the way the program works now is not why I subscribed to it in the first place.
(If, by chance, this was done to prevent cat-fishing or other nefarious uses, I doubt the people doing that are toggling the voices on and off repeatedly when trying to fool people. So, as said, not a very productive change.)
Edit:
Apparently that option was re-implemented, but I did a fresh install with the website's newest version and it's still not there, so... Not sure if that's true or not.