Regularity and irregularity in wind instruments with toneholes or bells

ISMA 11 Homogeneity of emission and timbre of musical instruments is a difficult issue. Intuitively it can be related to the regularity of the geometry, even if this relation is another difficult issue. The present talk aims at contribute to the discussion about the regularity of both woodwind and brass instruments. Benade published a paper in 1960 where woodwinds were modeled as periodic media with regular toneholes. In 1974, with Jansson, he compared bells of brass instruments and exponential horns. He had a particular interest in both the definition and the effects of cutoff frequencies for wind instruments. Recently we discussed a definition of acoustic regularity in the context of woodwinds. This work is first summarized, then some open questions are discussed concerning instruments with toneholes and with bells, starting with an analogy between exponential horns and periodic lattice of toneholes.