DeLio’s approach to composition is largely influenced by Morton Feldman, John Cage, and Iannis Xenakis. The influence of Xenakis, however, is often more philosophical than musical. Describing the influence of Xenakis and Feldman, DeLio explains:
Xenakis and Feldman are influences in the general sense that they each tap into very personal and unique sensibilities; in this sense they should be role models for all composers. Also, for these composers, sound is the source of the compositional process. Sound, in all its richness and complexity, is the essence of that process for both — not system of method or gesture, as is the case for so many composers. This is true for me as well. First and foremost I think about sound when I start a piece.
The primary area where Xenakis and DeLio differ is in the use of mathematics, which is integral in Xenakis's compositions. DeLio states, “My music is not really mathematical at all!”
The influence of Cage is evident in DeLio's use of sounds outside of the standard dodecaphonic system. “Prior to the 20th century,” DeLio notes, “the sonic materials of Western music were restricted to a set of twelve pitch classes. Over the course of the past hundred years, this restriction has virtually disappeared.” Elsewhere, DeLio describes his attraction to percussion instruments, explaining, “Percussion allows a composer to deal with sounds drawn from the entire pitch/noise continuum. Thus, pitch is one manifestation of all sound ranging from pure tones to noise bands.” Cage was a pioneer in this area, writing for a wide variety of percussion instrument, electronic devices, and even household objects to produce new sounds. Composers like DeLio are heavily indebted to his work.
Another area where the influences of Cage and Feldman are strongly felt is in DeLio’s extensive use of silence as a compositional device. On the surface, in fact, DeLio's music bears a strong resemblance to the music of Cage and Feldman, both of whom made extensive use of sparse textures and were not afraid to use silence as a key part of their compositions. Upon further examination, however, one finds that the function of silence in music varies significantly among the three composers. Feldman, for example used silence to separate sounds and give them space to fade into silence. DeLio notes, “Feldman once said that one of the most beautiful things a sound does is decay. He could have added that in order for this decay to be felt, it must be attached to silence.” Cage, on the other hand, used silence as a compositional tool for incorporating unintentional, atmospheric sounds into the context of a musical composition. DeLio explains, “Cage, of course, is the real source of all consideration of silence in music. But even his approach to silence is not like mine — though I deeply admire his work. For Cage silence is the space in which all unintended sounds come into play.” DeLio’s use of silence is different in that it is used to isolate sounds and events. He explains:
While this may sound similar to Feldman’s use of silence, DeLio’s approach is more radical, using large units of silence to not only isolate the events sonically, but also to isolate them mentally, leaving so much space that the memory will often forget one gesture before the next is presented, essentially forcing the listener to evaluate them as separate, unrelated musical entities. DeLio explains: