Soundstream 1.5 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
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. The program is included in Theming Tools. This free software for Mac OS X was originally developed by PCheese.
From the developer:
Soundstream is a Mac OS X screensaver that reacts to sound input. Its colorful Flurry-like streams pulse to the beat of the music or bloom with the ambient noise. Soundstream looks great as a replacement to the iTunes visualizer, pulsing appropriately to the music.
You may want to check out more Mac applications, such as scarytime v9, ShadeIt! or System47, which might be similar to Soundstream.