Gil writes about these pieces:
Untitled (for Po Chu-i) has to do mainly with the sound of air inside small and medium chambers such as a large bottle, the inside of a guitar, a long cardboard tube, etc. This process of selecting a chamber or a number of chambers has the property of giving a tonal undercurrent to any stretch of incidental sound recorded inside of it, and the simple act of layering one or two more recordings of different chambers can give enough tonal interest as to engage the listener. The incidental sounds themselves are already blurred by the sound and tone of the chamber, filtering some frequencies and highlighting others. The ancient Chinese poem revels in its uneventfulness and so does this piece, which is basically just long stretches of coloured silences.