Just put together a sage online simulator that lets you make your own spectrum with three different components.
Sage is a great package which allows for open-source mathematics with many different packages. It also comes with a nice notebook interface and has great interactive plotting capabilities with sliders and different inputs. It can also display Latex in the html.
I want to add in a singular value decomposition and show how the different components are extracted from the spectrum. It would also be good to get interface more responsive,