According to the composer, the sonata for alto saxophone and piano, which he regards as his first mature composition, takes its title from the astronomical term referring to the spacetime boundary in a black hole beyond which light can no longer escape - a point of no return. Event Horizons is an intensely emotional piece, stemming from reflections on the immensity of the universe and one's own place in it. The title was merely a catalyst, an image that sparked the creative process. Whittall was also greatly affected by the spaciousness and subtle intricacies of Eastern music - the gamelan music of Bali in particularly.

Much of the resulting music is reminiscent of the ringing of bells or gongs, which in so many cultures has great ceremonial and spiritual importance. They can be seen as a symbol of connection between the natural and meta-physical worlds. At its core, Event Horizons is an intense rite of passage, a quest for ultimate understanding, and perhaps reaches it, at least in part.

Säveltäjän mukaan teos on saanut nimensä astronomiasta, jossa Event Horizon, tapahtumahorisontti, viittaa tila-aikaan mustan aukon tuolla puolen, josta valokaan ei enää pääse pakenemaan. Teoksessa on tunteellinen lataus, joka syntyy suuren maailmankaikkeuden koosta ja ihmisen omasta paikasta siinä kaikkeudessa. Sinällään otsikko oli vain katalyytti, kuva, joka käynnisti teoksen luovan prosessin. Myös itäisten musiikkikulttuureiden kellot ja gongit, pitkään soivat äänet - etenkin balilaisessa gamelanmusiikissa - ovat vaikuttaneet teoksen äänimaailmaan.