The Dartmouth Digital Synthesizer, also known as the Synclavier, was developed in the late 1970's by Jon Appleton with New England Digital co-founders Sydney Alonso and Cameron Jones. Heard on these four compositions, I believe, is the Synclavier I or a prototype thereof. The Synclavier I and its successor, the more commercial Synclavier II, used Frequency Modulation synthesis and were instrumental in further development of digital synthesizers. FM synthesis creates rich and colorful sounds that, prior to it's advent, hadn't been heard. You can hear the dynamic qualities and how they differ from other early synthesizer pieces, yet still at times sounding experimental, but at others, meditative and leaning almost towards melodic.
Again, since this is a Folkways title, it is recommended that if you like the album, purchase it.
There will be more on Jon Appleton in the future. For now, enjoy.