The eight pieces on this double disc were written between 1995 and 2001 towards the end of Tenney's life.. "Each is scored for a different chamber ensemble, so they have considerable timbral variety, but it's their single-minded aesthetic unity that is most striking; this is largely slow music consisting largely of sustained tones, although the speed of the changes and the length of the durations evolve within each piece"

• 1-1 Spectrum 1 (1995)
• 1-2 Spectrum 2 (1995)
• 1-3 Spectrum 3 (1995)
• 1-4 Spectrum 4 (1995)
• 2-1 Spectrum (1995)
• 2-2 Spectrum 6 (2001)
• 2-3 Spectrum 7 (2001)
• 2-4 Spectrum 8 (2001)