Self-tuning theorem: delta-band brainwave entrainment is guaranteed for any chant frequency

From the original synthesis page (Session 5migration). Claim: the modular arithmetic of the chamber's standing-wave comb means that for any vocal frequency f ∈ [50, 5000] Hz, the beat between f and the nearest water-hammer harmonic lies in the delta band. Therefore "a person inside the coffer cannot not experience delta entrainment." Argue.