4080 posts since 7 Oct, 2005, from Auckland - NZ
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
Windows 10 PC with Waldorf Blofeld as my synth/midi controller and HS7 as monitors.
Cubase 9/ Reaper 5/ FL Studio 12 with synths/instruments/effects mainly from u-he, Air, NI, Steinberg, Waves, Sonivox and Synapse Audio.