Friday, December 10, 2004

Journal Club: Farewell to the Crematorium

My students have made their last posts to The Musical Crematorium, scripts for presentations of scientific research on music. They each picked a journal article to present, and were required to completely script their presentation, accounting for necessary language shifts from a written format to an oral presentation. They gave their presentations on Wednesday and today, and turned in their final portfolios. Now I need to read and grade them! I will turn the administration of The Musical Crematorium over to interested students, who may want to keep blogging. I am quite happy with the maiden voyage of class blogging (for me), and plan to use this quite often in the future.

To make this post a double whammy of seminar stuff and Journal Club stuff, I will fill in some gaps of a few presentations.

"Speech Patterns Heard Early in Life Influence Later Perception of the Tritone Paradox" examines one of Diana Deutsch's main research topics, the tritone paradox. There is a musical sound called the Shepard's tone, which is designed to be registerally ambiguous. A listener can tell that a C was played, but not which octave placement of that C. It sounds much like an organ stop, with lots of different registers involved in a big bell curved amplitude arrangement. Deutsch found an interesting phenomenon when using Shepard's tones to examine the perception of musical intervals. When the two notes of the interval were spaced a tritone apart, exactly one half of an octave, listeners disagreed whether the first note was higher than the second note. With any other melodic interval there was complete agreement on ascending or descending sounds. But at the tritone, some listeners would judge the interval as ascending and others as descending. This particular article shows that the language learned as a child biases a person towards a particular frequency range, and thus affects how the tritone is perceived. This is a very interesting link between music and language.

"Music in everyday life" doesn't have any gaps, but it does describe an interesting experiment that many of you will find interesting, so I am pointing it out. People were surveyed via cell phone texting to find out what role music has in the span of a normal day. Many of the results are predictable, but one was quite surprising: most people listen to music in the company of others, rather than alone. I still wonder if listening to one's iPod while standing near other people counts as social listening, since the others can't hear the same music.

"Vowel Modification Revisited" is a less scientific article, and the presentation misses most of the science that is present. First a brief explanation of formants. All pitched sounds are made up of many frequencies, even if we only hear one frequency/pitch. The difference in the amplitude of upper frequencies cause the difference in tone quality that makes a clarinet sound different from a flute, a cello different from a trombone. When speaking or singing, a person changes the shape of his/her mouth, nasal passages, and throat to favor various ranges of frequencies. These ranges are the formants, which determine the vowel sound we hear. An 'o' has lower formants (usually only the first two are considered) than 'ah' or 'ee'. The article shows how singers alter the formants from typical positions as associated with a given vowel. Bright vowels, like 'ee' are made darker when singing higher notes. An article from Nature is a better scientific take on this subject, "Tuning of vocal tract resonances by sopranos". The authors have made an online page with sound files demonstrating the vowel shifts, and some additional definitions of formants and the physics of singing. Note the challenge to sopranos in the middle of the page, to make clearly perceived differences in vowel sounds at high registers. It is really a challenge to anyone with access to a willing soprano, to see if you can perceive vowel differences at high registers.

The other posts are on emotional intelligence and musical performance, the spatial perception of music, and absolute pitch (the technical name for perfect pitch). Thanks to everyone who did make comments on the blog. It meant a lot to the students to get feedback from "outsiders."

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