SC Infinity Synth 5.5.6 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This software for Mac OS X is an intellectual property of Stagecraft Software. The software is included in Audio & Video Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
SC Infinity Synth is a sample-based synth designed for maximum expressiveness. Additional samples and patches can be auditioned and purchased directly from the synth, allowing you to create your own custom, infinitely large sample bank. You can use automation to create anything from that wobble characteristic of so much dubstep, to a voice that comes in and out at random intervals, effects that fade in and out with perfect, quantized precision.
You may want to check out more Mac applications, such as Pexip Infinity Connect, Marathon Infinity or Infinity Wars 2014: Animated Trading Card Game, which might be similar to SC Infinity Synth.