tag:blogger.com,1999:blog-6919674981128634746.post1767063130005087669..comments2023-11-05T07:41:34.380-05:00Comments on Kashu-do (歌手道): The Way of the Singer: Kashu-do (歌手道): STRUCTURE OF THE VOCAL FOLDS: A three-dimensional view Kashu-Dohttp://www.blogger.com/profile/17375903978220316261noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-6919674981128634746.post-6606234716268742017-10-17T15:14:51.591-04:002017-10-17T15:14:51.591-04:00Another excellent article! Thank you!Another excellent article! Thank you!Anonymoushttps://www.blogger.com/profile/04796498390408771247noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-55903121332446761272015-07-16T13:04:42.420-04:002015-07-16T13:04:42.420-04:00OK, you talk about X, Y, and Z, but I have to say ...OK, you talk about X, Y, and Z, but I have to say that I don’t understand your coordinate system :( And as far as I can understand, there is no coordinate system defined in the article either… Anyway, what Hollien calls total vocal fold mass (TVFM) is, in his terminology, L x T, length times “thickness”. (You may have misunderstood this since you talk about the length as the “Z value”). And what Hollien calls “thickness” is really what you call “depth”. (If I don’t misread him, that is. The article is not crystal clear everywhere.) So “mass” for him is <b> length times depth </b>. <br /><br />Moreover, the conclusion from the article is that it is the <b>depth</b> of the vocal fold that is relatively constant for each absolute pitch across voice types, and the depth shrinks very strongly with increasing pitch. This is certainly a very significant conclusion! In contrast, TVFM differs a lot between voice types, but it is more or less constant over the pitch range. This makes me suspect that TVFM is really a measure of the total amount of tissue, which of course does not change. The shape of the folds change under muscle action, but the total volume does not. <br /><br />I think what Hollien really is studying is the general, gross posture of the folds, where the most significant conclusion, from what I understand, is the lengthening of the folds with pitch and the strong thinning of depth with pitch. However, which parts and how much of the folds that are active in the vibration is not really studied, except perhaps the stroboscopic pictures of figure 8, which seems to indicate that it is mostly the top part of the folds that vibrate at that pitch. I suspect that this type of phonation hurts a little; it may have been me before starting studying with you :)Martin Berggrenhttps://www.blogger.com/profile/09015025825598248479noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-80225209558091126692015-07-15T09:37:32.162-04:002015-07-15T09:37:32.162-04:00I understan Martin. What is significant here howe...I understan Martin. What is significant here however is that the "area" X x Y is relatively constant for all voice types on a given F0. It is understood that the Z axis which represents the actual A-P length is not considered in its entirety. What he calls mass is X times Y times a given Z value (I believe). It is understood that the different voice types have different total A-P lengths (Z). Since the vibration cycle for the voice is based primary on the value of X-axis it is significant that the value of X is the same irrespective of voice type. Whether or not someone produces an efficient tone that isolates the fold cover or not is a question of refinement. That the X value is the same means that we can expect certain norms relative to F0 production. That is significant. More focused studies need to be done on the finer variations of this "cross-sectional mass" to determine the parameters of efficiency among professionals and between pros and non-pros.<br /><br />Longitudinal tension is obviously going to have in effect on what part of the horizontal thickness will be active in vibration and we should not expect the actual vibratory mass to be the same among singers. Two tenors of different weight will have different thickness of fold cover. That is not going to have an effect on the speed of the vibration cycle. What does is whether the X value is constant for both and I think the findings of this study imply that the X values will be closely similar across voice types.<br /> Kashu-Dohttps://www.blogger.com/profile/17375903978220316261noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-80044015173582684282015-07-14T16:47:34.991-04:002015-07-14T16:47:34.991-04:00So, now I've gone through the article by Holli...So, now I've gone through the article by Hollien. The article, although published in 2014, does not really report any new findings, but reviews and compiles results, where most of the primary measurements were done already in the beginning of the 1960s.<br /><br />It should be stressed that trained singers are explicitly excluded from Hollien's studies!<br /><br />The main question I have about Hollien’s article is: what quantities are really measured? A main conclusions (Table 4 and 5) is that what the author calls <b>total vocal fold mass</b> (TVFM) is more or less constant for each individual across all pitches! Moreover, the TVFM is strongly correlated to voice type; its mean values, from which is differs very little for different pitches, are 558, 342, 221, 137 (unit unclear) for low male, high male, low female, and high female, respectively. <br /><br />This sounded at first very strange to me, until I realized that TVFM likely <i>don't</i> corresponds to effective vibrating mass! What the authors of the original articles have done is to look at ordinary and X-ray pictures of the vocal folds and measured the horizontal length of the fold and the area of a vertical cross section of the folds, that is, roughly the red, yellow, and orange regions of your animated gifs above. From this area, which also includes the underlying muscle, a vocal fold <b>depth</b> is calculated (Hollien calls it “thickness”, but it really seems to be the depth). This depth seems to correlate strongly with absolute pitch across voice types; it decreases rapidly with increasing pitch. The TVFM is then defined as the length multiplied with the depth. (To me this seems like area rather than mass, but OK…)<br /><br />With this in mind, the conclusion that the TVFM is constant for each person but varies with voice type, simply tells me that the total volume of the vocal folds don’t change, which seems absolutely reasonable. The shape changes, but not the volume; it has simply nowhere to go! What happens is that the depth decreases and the length increases with increasing pitch, which also seems reasonable because of CT action. <br /><br />However, a large portion of TVFM is likely not active at all in the vibration, and I don’t think the results gives much indication about the effective vibrating mass at different pitches and for different voice types.<br />Martin Berggrenhttps://www.blogger.com/profile/09015025825598248479noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-51344236117268512602015-07-14T00:13:17.062-04:002015-07-14T00:13:17.062-04:00Isn't the difference therefore more a questio...Isn't the difference therefore more a question of the percentage of the overall mass that is isolated to vibrate and what acoustic function is played by the non-vibrating portion of the instrument in question. such that a cello playing the same note has a greater overall mass and a smaller percentage of the string is actively vibrating?Kashu-Dohttps://www.blogger.com/profile/17375903978220316261noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-4396986986346824752015-07-14T00:09:31.805-04:002015-07-14T00:09:31.805-04:00This is an argument I made quite a while ago, and ...This is an argument I made quite a while ago, and it always seemed logical to me. Although the mass would be close to the same, the longitudinal tension would be different. The folds are more relaxed for a soprano singing F4 than a bass singing the same pitch. The soprano is in her low range while the bass is at his top. How is the cello string different? Even if the overall mass is considerably larger than the violin, because the strings are stopped, isn't the vibrating portion more or less the same? The mechanism of fold vibration is slightly different in the way the air is propagated. Could this play a part?<br />Kashu-Dohttps://www.blogger.com/profile/17375903978220316261noreply@blogger.comtag:blogger.com,1999:blog-6919674981128634746.post-63452641344704506632015-07-13T17:51:41.862-04:002015-07-13T17:51:41.862-04:00(My comment from yesterday didn't seem to go ...(My comment from yesterday didn't seem to go through, so I'll make a second try!)<br /><br />Thanks for a thorough treatment! I will need to go through this slowly, and also read the interesting article you pointed to (Just downloaded it). Luckily, I have a full day of travel tomorrow to go through the stuff!<br /><br />I am quite surprised over the quoted conclusion, that the vibrating mass should be the same for the same absolute pitch regardless of whether a bass or a soprano are singing the note. Can this really be true? I have always thought that the difference should be similar to the difference between a double bass and a violin playing the same pitch. That is, the vibrating mass of the bass string is higher, and to compensate for that, the tension is higher. (In general, the simplest “lumped” model of vibration is that the square of the frequency is proportional to the tension divided by the mass.)<br /><br />Well, I will read the article and will return with thoughts about this fascinating issue! Martin Berggrenhttps://www.blogger.com/profile/09015025825598248479noreply@blogger.com