AIR PRESSURE AND RATE OF FLOW
FOR DOUBLE REEDS
Stephen I. Schellenberg,
Eugene, Oregon

As wind players, we are constantly striving for maximum efficiency in the use of air. We all have our ways of maximizing relaxation and achieving the optimum sound when we play. Many of the ways we think about breathing could almost be termed "Zen and the art of double reed playing". We conceptualize a sensation of relaxed playing and then attempt to achieve it, in a manner very similar to the "inner game" concepts of Timothy Gallwey (1974). Such ways of dealing with breathing often work because they bypass analytical thinking and concentrate on the natural aspects of breathing as part of the total sensation. However, when "inner game" concepts fail to work, either for us or for our students, we need a knowledge both of basic breathing physiology and of the physical ways in which air works on the reed.

Numerous articles and chapters of books have been written on the physiology of breathing. (A good brief article with a useful bibliography was written by James Lakin in the April, 1969 issue of Instrumentalist.) Although Taylor (1968) and others have found common misconceptions, especially regarding the precise function of the diaphragm, this topic seems to be fairly well understood by most wind players. Far less understood is the interaction of rates of air flow air pressure and range on the double reeds. These parameters have been studied extensively by Arnold Jacobs, who found that for each of air flow and pressure a single curve could be drawn that would include all brasses. That is, for notes of identical pitch, air pressure and flow rate were virtually the same for all brasses regardless of different instrument dimensions. The current study investigated whether this phenomenon also holds true for double reeds. It also attempted to determine the relationship between air pressure and rate of flow, independent of range.

Test pitches chosen as representative of low, middle and high ranges respectively were the three octaves of D for the oboe and low C, third space D and F above the staff for bassoon. Each pitch was played four times and results averaged to account for measurement error.

Results -- Means and standard deviations for all measurements are presented in Table 1. As expected, pressure increased and rate of flow decreased as pitch rose. Statistical analysis showed these trends to be basically linear for each instrument, that is, approximately the same change is involved in either octave. Results of the analysis are presented in Tables 2 and 3 at the end of this paper, for the statistically minded. The meaning of the analysis may become clearer through examination of Figures 1 and 2. These graphs make it obvious that something very similar to Mr. Jacobs' single curve for brasses pertains for double reeds, although a decisive statistical test with the current data is hard to find.

Correlations of pressure and flow for each of the test pitches were calculated. In general, they were positive, but none were significant. Partial correlations of pressure and flow with the effect of range removed were also calculated for each instrument. Again, they were positive but not significant.

The Study

Subjects -- The subjects in this study were all either advanced university students, university faculty, or professional performers from the Pacific Northwest. Seven oboists and seven bassoonists participated. Subjects were tested individually at various times over a four-month period.

Method -- Each subject first had vital capacity measured using a Vitalator calibrated bellows. This measurement was taken at least twice to ensure accuracy. Subjects were then instructed to take a full breath and play the test pitch for a specified number of seconds (experimenter timing). Residual air was then blown into the Vitalator and the difference from capacity was used to calculate rate of flow per second. The tube from a pressure gauge was held in the corner of the mouth while playing and the meter was read by the experimenter.

Discussion -- This study suggests very strongly that pressure and flow are as much a function of the range in which we are playing as of the way we play. However, looking at some individual cases in a rather non-analytic way, some opposing possibilities emerge. Two of the bassoonists, both principal players in professional orchestras, showed similar patterns of above average rates of flow with average or below average pressure. Although their dynamic level was not noticeably higher, both players had a presence and projection in their sounds that was not as noticeable in many of the other bassoonists. Among the oboes, the two most experienced professionals both also had higher rates of flow, but in this case with average or higher pressure. These instances, as well as the low pressure-flow correlations, suggest two possibilities. First, high intra-oral pressure may not have much to do with getting a lot of air through the instrument. Second, rate of air flow is the larger factor in good tone production. The way of getting higher air flow, of course, is different for every player.

Perhaps this study has shown more than anything else the need for further research in this area. A larger sample would give more decisive correlations. Effects of different reed styles needs to be known (although I suspect this is not nearly so great as we think -- look at the similarities for oboe and bassoon in the same range and then look at their reeds). Above all, ways of using this knowledge to help where the "inner game" has failed are needed.

References

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