Well Tempered Tuning Cannot Account for Low Purity Ratings of Isolated Voice Parts

Since Western people usually hear melodies in well tempered tunings, it is doubtful whether laymen would use a pure tuning as a reference when asked to judge whether a certain melody is sung in tune or not. In an earlier class room experiment among approximately 274 pupils (average age 15.6; SD 0.9) the isolated voice part of several songs was rated less in tune than the same voice part presented with the original accompaniment, although every mistuning was digitally corrected. It was hypothesized that these differences were due to the fact that music processing is more difficult without accompaniment defining rhythm and harmony. The aim of the current experiment was to test the competing hypothesis that purity ratings in conditions without accompaniment are affected by the fact that in a capella conditions a pure tuning is expected. To test this, 32 of the pupils that also participated in the earlier experiment (mean age 15.5; SD = 0.5) and 36 adults (average age 56; SD = 15), rated the purity of the singing in six excerpts of the same songs in two conditions: pure tuning and well tempered tuning. The results indicate that in general there is no significant difference between purity ratings for excerpts in pure tuning, and excerpts in well tempered tuning. Among adults and pupils separately there are no differences. Among the total population, the pure tuning of one excerpt is significantly higher. Musical experience seems to have a small but interesting effect on purity ratings. Experienced musicians give relatively high purity ratings in both conditions, but tend to rate pure tunings slightly higher than well tempered ones, whereas listeners with moderate musical experience tend to rate well tempered tunings slightly higher.