Source Filter

Question 1

In regards to the Source Filter theory, what role do the vocal folds play?

Answer 1

Vocal Folds

• Source of Acoustic Energy
• Their movement (as well as their contact and closure time) alters transglottal airflow.

Question 2

In regards to the Source Filter theory, what role does the Vocal Tract play?

Answer 2

Vocal Tract

- Selective Sound Filter

Question 3

What are some features of the Source Spectral Slope?

Answer 3

Source Spectral Slope

• Relative Amplitude (dB) Vertically and Frequency (kHz) Horizontally on the graph (harmonics - left to right).
• Drop off of 18 dB per Octave for whispered speech.
• Drop off of 12 dB per Octave for regular speech production.
• Drop off of 6dB per Octave for robust sound production (opera).

PAGE 130 of Titze!

Question 4

Define Formants?

Answer 4

Formants - Resonances of the Vocal Tract

• They vary depending on the Size/Shape of the vocal tract.
• Potential Resonant Energy

Question 5

Which Formants determine the Vowels?

Answer 5

Lowest two Fomants determine the Vowels

* AKA - Vowel Formants

Question 6

What is the Singers Formant Cluster?

Answer 6

Singers Formant Cluster - F3, F4, F5 (Potential energy could be clustered together - a team of resonances that uniformly boosts certain frequencies.

Question 7

What part do Vowels play in Resonance?

Answer 7

Vowels Create Spaces in Vocal Tract

Spaces have Inherent Pitches

Inherent Pitches need to be:

• Acoustically sensitive to the Harmonics produced at the vocal fold level, or
• Modified to become more Acoustically Sensitive.

Question 8

Lilli Lehmann Resonance Quote and The goal of Resonance?

Answer 8

Lilli Lehmann says…. “Sing on pure resonance, not pure vowels”

*Focus on the goal:
Provide audience with a constant amount of acoustic information with as unified a timbre as possible so as to sound like one voice. Functionally you also enhance the vocal fold vibration with good tuning.

Question 9

Why is there a need to modify vowels?

Answer 9

Vowels have certain acoustic properties that make them more effective in some pitch ranges and less effective in others, hence the need to modify.

Question 10

What are the characteristics of the vowels from the three charts showing tongue position and the resultant space in the pharynx?

Answer 10

Vowels - (Potential energy)

• ah Vowel (as in FATHER) - less space in back and more in front: boosts occur at 800 and 1200 and 2600 Hz
• i Vowel (as in HEED) - More pharyngeal space, less oral cavity space - big boost at 300, and 2200, and 3200 Hz
• OO Vowel (as in Pool) - more pharyngeal space than ah, and more oral space than the ‘i’ vowel - Boost at 400 & 800 Hz

Question 11

How could a person determine the formant frequencies of their vocal tract.

Answer 11

USING VOCAL FRY - excites vocal tract space. Dr. Gill located where his 1st and 2nd Formants where by using vocal fry with the 5 main vowels. He then recorded himself speaking the vowels - and then compared the two Spectrums. Then second had spectrum displayed the realized boost in harmonics.

Question 12

What do F3, F4, & F5 control?

Answer 12

F3,F4 & F5 Control Timbre - when they cluster there is increased ring, when they move apart less ring.

Question 13

What is a Long Term Average Spectrum?

Answer 13

Long Term Average Spectrum - analysis of which formants are prominent over a certain duration of time.

Question 14

What are some things to consider in regards to men and woman and the Singers Formant Cluster?

Answer 14

For Men there is a boost in 2,500 to 3,200 Formant Clusters (F3, F4 & F5).

For Women - Orchestras are loudest below 500Hz, and Woman generally sing above 500Hz. So they dont rely on the cluster. Their Fundamental Frequency is high enough to be heard over an orchestra. The higher the F0, the further apart the Harmonics are, which is why it isn’t beneficial for woman to have a Singers Formant Cluster.

Take into consideration tissue damage - Women singing at high frequencies with high percentage of glottal closure will get stronger higher harmonics, but will come with a tissue cost.

Question 15

Where is the Actor/Speakers Formant located?

Answer 15

Singer or Actors Formant - 3,500 or 4,500 (at F4,F5). *does not include F3, which is included in the Singers Formant.

Question 16

What are 4 general rules for Vowel Modification?

Answer 16

General Rules

• Increase vocal tract length, i.e Round lips or Lower Larynx
• All Formant Frequencies uniformly decrease
• Decrease vocal tract length, i.e Spread lips or Raise Larynx
• All Formant frequencies uniformly increase
• Mouth Constriction
• Lowers F1, Raises F2.
• Pharyngeal Constriction
• Raises F1, Lowers F2

Question 17

Where does the Male Secondo Passagio typically lie? and where do the passaggios typically occur for Male voice types?

Answer 17

Male Secondo Passagio typically lies somewhere between D4 and G4 depending on voice type.

Bass - D4 to E4

Bass/Baritone - Eb4 (D4) to F4 (E4)

Baritone - E4(Eb4) to F#4(F4)

Tenor - F4(F#4) to G4 (G#4) in rare circumstances G4 to A4

Question 18

What are typical Male tuning strategies for Classical and Non Classical styles?

Answer 18

Classical Mode - Male singers typically change tuning from F1/H2 to F2/H3 when moving into and above 2nd Passagio on back vowels.

Non Classical Mode - Male Singers will remain in their F1/H2 tuning (Back Vowels) into and above their 2nd passagio, a sort of “Male belt”, but ultimately transition to F2/H3 tuning. (Delayed passagio)

Question 19

Where does the Female Secondo Passagio typically lie? and where do the passaggios typically occur for Female voice types?

Answer 19

Female 2nd passagio typically lies somewhere between D5 and G5, depending on voice type:

Contralto - D5 to E5

Mezzo Soprano - Eb5 to F5

Soprano - E5(F5) to F#5(G5)

Question 20

What are typical Female tuning strategies for Classical and Non Classical styles?

Answer 20

Classical Mode - Female Singers typically change tuning from F2/H2 to F1/F0 when moving into and above their 2nd Passagio.

Non Classical Mode - Female singers remain in the F2/H2 tuning into and above their 2nd passagio, “female belt” - sometimes use F1/H2 or F2/H3 pre-passagio in belt.

Question 21

DR Gills Resonance Strategy Study -

Answer 21

Classical Vs Non-Classical (Dr. Gill and Dr. Sandberg) Study

Ascending/Descending scales

• Sung on Ah
• Applying two different strategies through the passagio
• then rated by expert teachers on whether or not the recording is usual of classical transition.
• rater reliability was accurate.
• 1st sung in Classical Formant Tuning strategy.
• 2nd sung in Non Classical Formant tuning Strategy (Takes out vibrato)
• First one changes tuning strategies on top note. Second one didn’t adjust resonant strategies.
• Lowering of First Formant Frequency, below H2 - is what lowered in the classical version for all 3 subjects. (Most of them closed their mouth as they went through the passagio).
• F2 was near or just below H3.
• F1 has the most force - Dominant Formant, if both formants are tuned.
• F1 and F2 are typically lower in the Classical than in the non classical tuning, especially in the passagio.

Question 22

Describe the Source/Filter Theory -

Answer 22

Source filter theory: Vocal Folds or Transglottal Air Flow are the Source of Acoustic Energy that produce the sound. That sound energy passes through a filter. That filter is the Vocal tract, which shapes the sound. The way in which the vocal tract is shaped controls which harmonics are the strongest (get a boost).

Question 23

Describe what resonance is (Non Linear Model) -

Answer 23

Resonance: Back and forth relationship between the resonator (Vocal Tract) and the vibrator (Vocal Folds). When the Resonator is working well and encouraging the information from the source in a constructive way, then the vocal folds vibrate more evenly and easily. When the vocal tract is Destructive in regard to the frequencies that are passing through it, then the vocal folds start to vibrate less evenly, and more subglottic pressure is brought on to get more sound from the source.