Kangas Sound Editor demo
In this short demo of the Kangas Sound Editor, you can see and hear a seventh chord (one I prepared earlier) being computed and played. This video barely scratches the surface of what the Kangas Sound Editor can do, there are some additional videos on the Kangasrus channel that explore the functionality in a little more depth.
This video was actually uploaded to YouTube back in 2008, I have only recently (July 2012) decided to made it public, to see whether or not it is of interest to anyone.
The Kangas Sound Editor home page is: http://www.kangasound.com/index.html