This interesting piece was written for a special organ in The Netherlands: The 1671 Pieter Backer-Organ in the Bonifaciuskerk in Medemblik.
The composer writes in his foreword:
"...One of the significant characteristics of this organ is that the 8'-Trumpet stop does not extend below middle C (c1). In the middle section of the piece this feature is exploited by drawing the Trumpet stop together with 8' Flute (which has full compass) and playing patterns which lie partly above and partly below middle C. This gives a charming, syncopated 'pop' effect."
So I used the splitted reed-stop of the Rückpositiv in the Utrecht-organ to reach this special effect.
The score: Boosey & Hawkes