Halo Channel Welcome Screen Music
From Halopedia, the Halo wiki
The Halo Channel Welcome Screen Music is a piece of music composed by Brian Trifon and Brian Lee White (under their duo of Finishing Move Inc.), played on a loop during the welcome screen of the Halo Channel. The piece consists of a repeating synth track with arpeggios fading in and out, accompanied by regular single piano notes. The piece plays on a loop in the Halo Channel, though an "Extended Cut" was uploaded to YouTube by Finishing Move Inc. coming in at a length of 13:33.
The extended cut featured in the official upload does not consist of the entire track used in Halo Channel, with the full piece demonstrating more variation with the underlying synth beat and moves toward a darker tone. This variation has not been officially released, though unofficial fan-loops are available on YouTube.