Two different techniques utilizing vocalization in clarinet performance were examined through a research study in which one subject (the author) played several tasks utilizing each technique with different played pitches, vocalized pitches, and dynamic levels for each task. The first technique was singing while playing, which is also sometimes referred to as growling. This technique is produced by engaging the vocal folds during regular clarinet performance to create a second vocalized pitch that resonates in the oral cavity and exits through the mouthpiece as part of the same air stream as that used by the vibrating reed. The second technique studied was a much more recently pioneered technique that the author has labelled humming while playing due to its similarity to traditional humming in vocal pedagogy. This technique is produced by filling the oral cavity with air, sealing it off from the rest of the vocal tract using the tongue and soft palate, and humming through the nasal cavity. The cheeks are simultaneously used to squeeze air into the mouthpiece to maintain the clarinet pitch, much like in the technique of circular breathing.

For the study, audio, nasalance, and intraoral pressure data were collected and analyzed. Audio was analyzed using spectrograms and root mean square measurements of sound pressure for intensity (IRMS). Analysis of the nasalance data confirmed the description of the physiological mechanisms used to generate the humming while playing technique, with nasalance values for this technique far exceeding those for both singing while playing and regular playing. Intraoral pressure data showed significant spikes in pressure during the transitions from the regular air stream to air stored in the oral cavity when humming while playing. Audio analysis showed that the dynamic range of each technique is similar to that of regular playing, and that each technique produces very different and distinct aural effects.

This information was then used to help create a method to assist performers in learning how to produce both singing and humming while playing and a resource to help educate composers about the possibilities and limitations of each technique.