978-1285198248 Chapter 5

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Phonation Lab 1

Visipitch

To the instructor: The Visipitch is a really useful tool to view the interaction between

fundamental frequency and intensity in real time. The great part about using Visipitch (or similar

tools) is that the student gets to manipulate her or his voice, more meaningfully. This activity is

pretty basic, and I’m sure you’ll find ways to change it to make it better! Please realize that these

instructions are very specific, so they may not be the same for your model of Visipitch. I have

left some elements that are clearly different for the newer Visipitch versions so that they are

accounted for, and I would recommend going through the lab and editing it to match your model.

Use of the Visipitch

Visipitch Demonstration

The Kay Visipitch is a very versatile tool but has limitations also. Let’s look at what it can do.

Definitions:

Optimal f0 (sometimes referred to as optimal pitch): This is the most efficient frequency of

vibration of your vocal folds, given their current physical characteristics.

Habitual f0 (habitual pitch): This is the frequency of vibration of your vocal folds during

everyday usage. There are many different stimulus situations that can be used for habitual f0.

We’ll use a reading passage and a counting task.

Vocal range: This is the range of vocal production, defined as the difference between the highest

frequency of clear vowel production (exclusive of falsetto) minus the lowest frequency of clear

vowel production (exclusive of glottal fry). I’m excluding falsetto and fry here because the

measure we want is of vocal range for modal phonation (modal phonation is the type of

phonation used for typical, or modal, speech production).

Vocal jitter (perturbation): Cycle-by-cycle variations in fundamental frequency.

1. If the computer isn’t on, turn it on and select Kay Control from the menu. You first need

to select the proper filter setting for your voice on the Visipitch box to the left, under the

2. Verify display. Sometimes the filter setting isn’t appropriate, and you need to change it. This

can happen because a person’s voice is too low or high in frequency or because the task

moves it out of range. To verify that you are in a good starting place, do the following:

d. If you see a nice straight line about 1/4 of the way up from the bottom of the screen,

you’re in business. If not, change filter settings and repeat this task until you see that

straight line.

e. Hit return to go back to the main menu

3. Identify habitual f0:

a. First, let’s lengthen the viewing time. Select “time display,” hit enter, and change it to 9

seconds and hit return.

“You wish to know all about my grandfather. Well he is nearly 93 years old and still

thinks as swiftly as ever.”

i. When you are satisfied with your production, you’ll want to mark it with cursors at the

beginning and end to exclude information you don’t want in the calculation. Use the

down/up arrows to move to “cursor” (under the display screen). Hit “L” to activate the

left cursor and use the right and left arrow keys to move it over until it is snugged up

4. Habitual f0 for spontaneous speech:

a. This is not quite spontaneous speech, but it will get us where we want to go. In this task

you should begin taking data again, but this time count, evenly, starting with one and

ending when you’ve filled up the screen.

b. When you’ve done that, cursor it as before, and then get to the statistics screen.

Mean f0 ________ Hz

Max. f0 ________ Hz

Min. f0 ________ Hz

Range ________ Hz

c. How do the numbers between the two tasks compare?

5. Identify optimal f0:

There are many different ways to identify the natural frequency for a given set of vocal folds.

The notion is that you want to set them into vibration under conditions of low muscular

tension, but with a clear phonation. One way is to relax and say “uh-huh” a couple of times.

Do this and then check your statistics.

Mean f0 ________ Hz

How does the mean for habitual and optimal f0 compare? In an ideal world they are about the

same.

6. Identify range of f0:

Admittedly, above you identified range of phonation during a speaking task. We are also

interested in range of phonation as a maximum function task. Do the following:

a. Minimum: Sustain an /a/ and glide down while holding down the microphone. Watch for

the point on the trace at which you get into glottal fry. If your trace went away or started

breaking up before your voice did, you may need to move the filter setting down to “A”

for this. When you are done you can cursor over with either the left or right cursor, put

the cursor on that last point, and read out the frequency at the cursor (see the lower right

screen). Alternately you can go into the “calculate statistics” screen, but if you went into

fry, you’ll need to cursor the fry out anyway. Do this task again and take the average of

the two.

Minimum f0: ________ Hz

Minimum f0: _________ Hz

Average: _________ Hz

b. Maximum: Now sustain an /a/ and glide up as far as you can. Watch on the trace and

remember when you went into falsetto because you don’t want to include that. You’ll

probably need to raise the filter setting up a notch (from B to C) to make sure you include

all the samples.

Maximum f0: ________ Hz

Maximum f0: _________ Hz

Average: _________ Hz

Now calculate your range: Minimum−Maximum = __________ Hz

How many octaves is that? We expect an adult to reveal a two octave range. Remember that

an octave is a doubling of frequency. Try to get a ballpark notion of the number of octaves

that encompasses your range.

d. Approximately how many octaves does your range include? __________

7. Measure vocal jitter. On Visipitch, vocal jitter is termed “perturbation.” Perturbation actually

reflects a modified algorithm or formula for calculation; Koike developed a way to adjust for

longer-term perturbations. Get ready to take a sample. Before you do, remember that for

Go to the statistics screen and look for perturbation. Enter that number below and then do

this again so that you have two measures. Take the average of those.

Trial 1:__________

Trial 2: __________

Average percentage of jitter = __________

How do you compare with our 1–2% criterion for normalcy? What factors could lead to an

abnormally high percentage of jitter? __________________________________________