Re: absolute pitch & formant frequency

[chen-gia tsai <tsai.cc@xxxxxxxxx>]

Dear all,

It seems that there are two models of AP/RP: (1) AP is regarded as (RP + pitch references); (2) RP is regarded as (AP + working memory). According to the second model, AP without RP is a negative syndrome. This approach is supported by the finding that some AP subjects without RP lacks the P300 component.

The first model views AP a positive syndrome, as AP subjects have pitch references that might not exist in RP subjects. I wonder whether the frequency scale in our brain is absolute of relative. Three years ago the issue of AP was discussed in a seminar on musicology. I can remember a very interesting question posed by a student: perception of vowels requires an absolute frequency scale, so everyone should have some type of AP.

If the wave of a tenor voice is compressed at the ratio of 0.9, a RP subject might be unaware of the change in pitch. However, a RP subject can still distinguish this sound from the original one. The compressed voice appears to be produced by a child, because all formant frequencies are shifted upward.

It is my feeling that we all use an absolute frequency scale at an early stage of auditory processing. For RP subjects, the information of absolute pitch is 'forgotten' at a higher stage because it is of little use (even in the perception of tone language). For AP subjects without RP, the information of absolute pitch is preserved and serves as the basis for extracting pitch relationships. That is why the right frontal area that subserves (spatial) working memory is less activated in AP subjects without RP during musical interval discrimination.

Studies on the surface area of temporale planum also suggest that AP without RP is a negative syndrome.


Chen-Gia Tsai

______________________________________
Chen-Gia Tsai
Ph.D Musicology, Humboldt University Berlin
http://www.yogimont.net/jia/



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