Robert Rich - Somnium. There is a short version on spotify which is really excellent.
On researching, this is available as an edited download ( which is what I am listening to on spotify), a DVD 7 hour job and also amazingly as an iphone app.
Almost 10 years after its initial release, this project return in the (revolutionary?) form of an App Album . Designed to run endlessly on your iPhone/iPod, it can play uninterrupted for much longer than the original seven hours. It will simply run until you stop it, or until your iPhone/iPod batteries run out.
As an App, the Somnium App is extremely 'bare-bone'. It was designed to liisten, not to watch.
In fact, there's only one page with the cover art, a slider (from 'slow' to 'slower') and a start button. After hitting Start and setting the volume, you're supposed to turn the device screen off and just listen...no need for any further visual distraction.
For the Somnium App version, Robert Rich has selected and isolated different passages which are sequenced randomly. This approach means that the music remains interesting enough to actively listen to when in 'slow' mode. When set to 'slower', there are less changes so the pace suits sleeping.
This also means a bit of a conceptual distraction from the original DVD, which followed the sleep cycle (relatively active, to deep sleep, to relatively active again before waking up).
The app version randomly cycles through various parts of the composition, so it does not exactly follow that 'cycle'. In the 'slow' (most active') setting, the music is indeed constantly changing, and stays interesting enough for active listening for a long time.
Really not so sure about the DVD as I prefer to listen to my music on the ipods and hifi's away from the main dvd surround system. Will think about it though. Definitely fancying the download and especially trying out said app on iphone/ipod touch.