 Ghosts I – IV material was implemented into Nine Inch Nails live performances typically as a distinct section of instrumental songs mid @-@ way through the show . Ghosts material was performed in this manner primarily as part of the Lights in the Sky tour in 2008 , immediately after the album 's release . During these segments the music was largely acoustic , as opposed to the electric instrumentation of other Nine Inch Nails live sets . The Ghosts segment included instrumentation from a marimba , harmonium , glockenspiel , double bass , banjo and various homemade percussion instruments . The Ghosts section was later scrapped for the " <unk> " and " Wave Goodbye " tours , as Reznor felt the instrumental songs did not fit with the set lists . 
