The prevailing practice within vocal pedagogy is to divide both men and women's voices into three registers. Men's voices are designated "chest", "head", and "falsetto" and women's voices are "chest", "middle", and "head". This way of classifying registers, however, is not universally accepted. Many vocal pedagogists blame this confusion on the incorrect use of the terms "chest register" and "head register". These professionals argue that, since all registers originate in laryngeal function, it is meaningless to speak of registers being produced in the chest or head. The vibratory sensations which are felt in these areas are resonance phenomena and should be described in terms related to resonance, not to registers. These vocal pedagogists prefer the terms "chest voice" and "head voice" over the term register. Many of the problems described as register problems are actually problems of resonance adjustment. This helps to explain the multiplicity of registers which some vocal pedagogists advocate. For more information on resonance, see Vocal resonation.