As in the case of a brass instrument, the shape and size of the resonance cavities in the body select some of the buzzing frequencies but diminish other ranges of frequencies. Notice that the /i/ soun...As in the case of a brass instrument, the shape and size of the resonance cavities in the body select some of the buzzing frequencies but diminish other ranges of frequencies. Notice that the /i/ sound ("ee" as in the word 'seat') for most speakers lies in the upper left of the graph so the first formant has low frequencies and the second formant has high frequencies.