3704 posts since 7 Oct, 2005, from Auckland
The best free digital synth for such sounds IMO is Carbon 2, but you need to install the free Reaktor player then the free Reaktor Factory Selection.
Reaktor synths are unrivalled in this field. For me it is much easier and faster to get the sound I want from these synths.
Sometimes, I need a monster's sound or a scary voice and Razor/Prism/Massive (ok this is not a Reaktor one
) are the commercial ones that I like for any digital sound, but I also highly recommend Carbon 2. I can easily buy it for $50!! It is really a powerful synth
i5 & i7 Windows 10 64bit, Presonus iTwo, PX-5S, Blofeld and Yamaha HS7.
Cubase 9 Artist, S1v3 Pro, FLS Producer, Reaper, and some nice soft synths and effects.