Vocal Warm-up Exercises & the Quantification of … Sciences and Disorders...Vocal Warm-up Exercises...

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Change in Intensity (dB SPL) Pre and Post VWUE vs PlaceboAll Subjects Mean Intensity Pre (dB) Mean Intensity Post (dB) Change in Mean Intensity (dB) VWUE 57.6639 60.3963 2.733 Placebo 55.375 55.9265 0.551 Difference in change following vocal warmup versus the placebo condition t = 3.88 dBA P<0.000 Intensity: Spectral measures: Vocal warm up exercises (VWUE) are considered es- sential for healthy singing technique (David, 1995; Sabol, 1995). Effects of VWUE are poorly understood (Sundberg, 1987). Although objective measures have been used to look at the effects of VWUE (Amir et al., 2005; Vin- turi et al., 2001), understanding the benefits of VWUE remains elusive (Elliot, 1995). A national survey of 508 collegiate voice instructors suggested that enhanced vocal flexibility is a pri- mary goal of VWUE (Meyer at al., 2009). Working assumption: Vocal flexibility is the ability to modulate pitch, vowel, and intensity of vocal performance in a rapid and smooth manner. Rationale: The development of non-invasive quanti- fication of vocal flexibility will support investigation of vocal exercise efficacy. Ultimately this may lead to more effective VWUE regimens and improved singer training. This pilot study explored acoustic criteria for evaluating vocal flexibility pre- and post-VWUE. Hypothesis: VWUE will lead to im- proved measures of fundamental frequency accuracy, stability, note -to-note transition speed, vocal intensity, and spectral measures. METHOD Subjects : 20 healthy, undergraduate voice majors 11 females, 9 males; ages 20-22 years old No singing or demanding speech for four hours prior to sample collection Recording apparatus and conditions: Samples were recorded with a headset-mounted omnidirectional condenser microphone (AKG HC 577) positioned 4cm from the subject’s corner of mouth. Audio signals were recorded at 96kHz, 24-bit sampling rate (uncompressed) utilizing a Marantz PMC661 Portable SD recorder. Recordings were made in a quiet research lab. Procedures : Each subject sang alternating pitch (perfect fifth, P 5 ) tasks on prescribed pitches, pre- and post-VWUE or pre- and post-placebo. Task 1: Sing a repeated P 5 (demo on keyboard) as accurately as possible at tempo established by metronome (120bpm). Task 2: Sing an accelerating P 5 “starting at a moderate tempo and then gradually accelerating until you reach your maximum speed.” [Not analyzed for this presentation.] VWUE: 10 minutes of semi-occluded straw exercises, flexibility exercises, and callisthenic tasks Placebo: 10 minutes of quiet conversation re: VWUE attitudes Singers fell into one of 4 vocal ranges. Target notes for each of the vocal ranges were as follows: Target Notes Corresponding Target Frequencies Range 1Bass: F3 and C4 174.61 Hz and 261.63 Hz Range 2Tenor: A3 and E4 220.00 Hz and 329.63 Hz Range 3Alto: F4 and C5 349.23 Hz and 523.25 Hz Range 4Soprano: A4 and E5 440.00 Hz and 659.26 Hz Audio Samples were captured with a digital audio recorder and analyzed with a KayPentax CSL 4500 using Real-Time Pitch. Vocalizations were trimmed to a “middle 8” cycles of this pattern. i.e. the first cycle was omitted and the “next 8” cycles were analyzed. Percent between target notes Reference lines were placed on the sample as follows: 1 semitone BELOW the upper target note and 1 semitone ABOVE the lower target note. All data points between these reference lines were considered “transition time.” CSL software tells percent of data points which are between the upper and lower reference lines. Intensity Intensity data were generated by analyz- ing the entire 8-cycle sample All subjects (20 out of 20) increased in intensity following actual vocal warmup Only 65% of subjects 13 out of 20) increased in intensity following the placebo condition. In this example, the measured interval ratio is 256.64 ÷ 171.54 =1.496 or 2.99:2 (3:2 being a perfect fifth) DISCUSSION AND CONCLUSIONS Outcome measures that were sensitive to the effects of vocal warm-up exercises included intensity and harmonics-to-noise ratio. Individual data analyses suggest that skill level of the singer may play a role in the selected outcome measures’ sensitivity to change. Findings suggest that self-perception of enhanced vocal flexibility may be associated with ease of generating sound of a sufficient vocal intensity and optimal quality. Future studies might consider similar measures with larger number of subjects and with a more demanding vocal task within a musical context. Future studies might also consider gender and voice type differences in response to VWUE. Fundamental frequency accuracy and stability, interval accuracy, and transition outcome measures did not yield statistically significant findings. Intensity and spectral content outcome measures yielded statistically significant findings. RESULTS Interval Accuracy Fundamental frequency data for the upper notes was extracted by placing 2 reference lines on the sample as follows: One line 2 semitones BELOW the upper target note and a second line arbitrarily high ABOVE the upper target frequency. All data points between these reference lines were considered “on target” for the upper note. Fundamental frequency data for the lower notes was extracted by placing 2 reference lines on the sample as follows: One line 2 semitones ABOVE the lower target frequency and a second line arbitrar- ily low BELOW the lower target frequency. All data points between these reference lines were considered “on target” for the lower note. “Interval Accuracy” was calculated by taking the ratio of the measured upper note fre- quency to the extracted lower note frequency. Measured upper note frequency ÷ Meas- ured lower note frequency = Interval Ratio. An interval ratio of 3 to 2 (or 1.5 to 1) corre- sponds to an interval of a perfect fifth. Vocal Warm-up Exercises & the Quantification of Singers’ Vocal Flexibility Western Washington University, Department of Communication Sciences and Disorders, Bellingham, Washington Barbara Mathers-Schmidt, PhD, David Meyer, DM, Tim Kraft, BS

Transcript of Vocal Warm-up Exercises & the Quantification of … Sciences and Disorders...Vocal Warm-up Exercises...

Page 1: Vocal Warm-up Exercises & the Quantification of … Sciences and Disorders...Vocal Warm-up Exercises & the Quantification of Singers’ Vocal Flexibility Western Washington University,

Change in Intensity (dB SPL) Pre and Post VWUE vs Placebo—All Subjects

Mean Intensity Pre (dB) Mean Intensity Post (dB) Change in Mean Intensity (dB)

VWUE 57.6639 60.3963 2.733

Placebo 55.375 55.9265 0.551

Difference in change following vocal warmup versus the placebo condition

t = 3.88 dBA P<0.000

Intensity:

Spectral measures:

Vocal warm up exercises (VWUE) are considered es-sential for healthy singing technique (David, 1995; Sabol, 1995).

Effects of VWUE are poorly understood (Sundberg,

1987). Although objective measures have been used to

look at the effects of VWUE (Amir et al., 2005; Vin-turi et al., 2001), understanding the benefits of VWUE remains elusive (Elliot, 1995).

A national survey of 508 collegiate voice instructors

suggested that enhanced vocal flexibility is a pri-mary goal of VWUE (Meyer at al., 2009).

Working assumption: Vocal flexibility is the ability

to modulate pitch, vowel, and intensity of vocal performance in a rapid and smooth manner.

Rationale: The development of non-invasive quanti-

fication of vocal flexibility will support investigation of vocal exercise efficacy. Ultimately this may lead to more effective VWUE regimens and improved singer training.

This pilot study explored acoustic criteria for evaluating vocal flexibility pre- and post-VWUE.

Hypothesis:

VWUE will lead to im-proved measures of fundamental frequency accuracy, stability, note-to-note transition speed, vocal intensity, and spectral measures.

METHOD Subjects:

20 healthy, undergraduate voice majors 11 females, 9 males; ages 20-22 years old No singing or demanding speech for four hours prior to sample collection

Recording apparatus and conditions:

Samples were recorded with a headset-mounted omnidirectional condenser microphone (AKG HC 577) positioned 4cm from the subject’s corner of mouth.

Audio signals were recorded at 96kHz, 24-bit sampling rate (uncompressed) utilizing a Marantz PMC661 Portable SD recorder. Recordings were made in a quiet research lab.

Procedures:

Each subject sang alternating pitch (perfect fifth, P5) tasks on prescribed pitches, pre- and post-VWUE or pre- and post-placebo. Task 1: Sing a repeated P5 (demo on keyboard) as accurately as possible at tempo established by metronome (120bpm). Task 2: Sing an accelerating P5 “starting at a moderate tempo and then gradually accelerating until you reach your maximum

speed.” [Not analyzed for this presentation.] VWUE: 10 minutes of semi-occluded straw exercises, flexibility exercises, and callisthenic tasks Placebo: 10 minutes of quiet conversation re: VWUE attitudes

Singers fell into one of 4 vocal ranges. Target notes for each of the vocal ranges were as follows: Target Notes Corresponding Target Frequencies Range 1—Bass: F3 and C4 174.61 Hz and 261.63 Hz Range 2—Tenor: A3 and E4 220.00 Hz and 329.63 Hz Range 3—Alto: F4 and C5 349.23 Hz and 523.25 Hz Range 4—Soprano: A4 and E5 440.00 Hz and 659.26 Hz

Audio Samples were captured with a digital audio recorder and analyzed with a KayPentax CSL 4500 using Real-Time Pitch. Vocalizations were trimmed to a “middle 8” cycles of this pattern. i.e. the first cycle was omitted and the “next 8” cycles were analyzed.

Percent between target notes Reference lines were placed on the sample as follows:

1 semitone BELOW the upper target note and 1 semitone ABOVE the lower target note. All data points between these reference lines were considered “transition time.” CSL software tells percent of data points which are between the upper and lower reference lines.

Intensity

Intensity data were generated by analyz-ing the entire 8-cycle sample

All subjects (20 out of 20) increased in intensity following actual vocal warmup

Only 65% of subjects 13 out of 20) increased in intensity following the placebo condition.

In this example, the measured interval ratio is 256.64 ÷ 171.54 =1.496 or 2.99:2 (3:2 being a perfect fifth)

DISCUSSION AND CONCLUSIONS Outcome measures that were sensitive to the effects of vocal warm-up exercises included intensity and harmonics-to-noise ratio.

Individual data analyses suggest that skill level of the singer may play a role in the selected outcome measures’ sensitivity to change.

Findings suggest that self-perception of enhanced vocal flexibility may be associated with ease of generating sound of a sufficient vocal intensity and optimal quality.

Future studies might consider similar measures with larger number of subjects and with a more demanding vocal task within a musical context.

Future studies might also consider gender and voice type differences in response to VWUE.

Fundamental frequency accuracy and stability, interval accuracy, and transition outcome measures did not yield statistically significant findings.

Intensity and spectral content outcome measures yielded statistically significant findings.

RESULTS

Interval Accuracy

Fundamental frequency data for the upper notes was extracted by placing 2 reference lines on the sample as follows:

One line 2 semitones BELOW the upper target note and a second line arbitrarily high ABOVE the upper target frequency. All data points between these reference lines were considered “on target” for the upper note.

Fundamental frequency data for the lower notes was extracted by placing 2 reference lines on the sample as follows:

One line 2 semitones ABOVE the lower target frequency and a second line arbitrar-ily low BELOW the lower target frequency. All data points between these reference lines were considered “on target” for the lower note.

“Interval Accuracy” was calculated by taking the ratio of the measured upper note fre-quency to the extracted lower note frequency. Measured upper note frequency ÷ Meas-ured lower note frequency = Interval Ratio. An interval ratio of 3 to 2 (or 1.5 to 1) corre-sponds to an interval of a perfect fifth.

Vocal Warm-up Exercises & the Quantification of Singers’ Vocal Flexibility

Western Washington University, Department of Communication Sciences and Disorders, Bellingham, Washington Barbara Mathers-Schmidt, PhD, David Meyer, DM, Tim Kraft, BS