After The Session: Introduction to Vocal Acoustics for Spoken and Sung Voice with Gökçe Kutsal

How can understanding the science of sound help us become more effective voice teachers, singers and researchers? In our recent two-part course, Introduction to Vocal Acoustics for Spoken and Sung Voice, Gökçe Kutsal explored the fascinating relationship between the physics of sound and the way we produce, hear and understand the human voice.

Vocal acoustics can initially seem like a complex subject, filled with unfamiliar terminology and technical concepts. However, Gökçe’s approach demonstrated how these principles can be broken down into accessible ideas, supported by visual examples, audio demonstrations and practical applications for voice professionals.

Spanning a range of topics, including understanding the basic properties of sound and exploring resonance, vocal registers and spectrograms, the sessions offered a foundation for interpreting the voice as an acoustic system.

Understanding the science of sound

The course began with the fundamentals of acoustics: the branch of physics concerned with sound. Gökçe introduced key concepts including frequency, amplitude, period and wavelength, explaining how these properties relate to the pitch, loudness and quality of the sounds we hear.

Understanding these principles provides a useful foundation for exploring how the voice works. For example, frequency describes the number of cycles a sound wave completes per second and is measured in hertz (Hz). In vocal production, frequency is closely associated with our perception of pitch. Amplitude, meanwhile, relates to the size of a wave and the acoustic energy it carries, helping us understand differences in perceived loudness.

Gökçe also explored how sound travels through the air as a series of pressure changes, using visual demonstrations to make otherwise abstract concepts easier to understand.

For voice practitioners, this knowledge offers more than scientific background. Acoustics can help us explain vocal phenomena, investigate changes in tone quality and resonance, and provide students with visual feedback to support their learning.

Importantly, acoustic analysis does not replace a trained ear. Instead, it provides an additional way to explore and interpret what we hear.

Harmonics and resonance: How the vocal tract shapes sound

One of the central themes of the course was the relationship between the sound produced by the vocal folds and the acoustic properties of the vocal tract.

When the vocal folds vibrate, they produce a fundamental frequency alongside a series of harmonics. As sound travels through the vocal tract, its shape influences which frequencies are amplified. These areas of amplification are known as formants.

Formants play an important role in shaping vowel identity and vocal tone quality. Small adjustments to the vocal tract, including changes in jaw opening, lip shape, tongue position and laryngeal height, can influence the relationship between harmonics and formants, changing the sound we produce.

Understanding this relationship can help teachers move beyond broad instructions such as “open the vowel” or “make the sound brighter”. By considering the acoustic principles behind these adjustments, practitioners can develop a more precise understanding of why a particular change might influence the voice in a certain way.

Gökçe also explored how these relationships become increasingly important as singers move higher in pitch. As pitch rises, the harmonics become more widely spaced, which can make it more difficult to maintain the same acoustic configuration used in speech or lower-pitched singing.

Formant tuning offers a way to address this challenge by adjusting the vocal tract to optimise the relationship between formants and harmonics. Depending on the desired sound, these adjustments can help singers maintain vocal efficiency, manage transitions across their range and achieve particular tonal qualities.

Exploring vocal registers and tone colour

The sessions also examined the acoustics of vocal registration, including the differences between chest-like and head-like qualities and the ways singers can navigate transitions between them.

Vocal registers are often described using terms such as chest voice and head voice, but these labels can encompass several different aspects of vocal experience, including sound quality, physical sensation and the underlying vibratory behaviour of the vocal folds.

Gökçe introduced the M0–M3 classification, which describes vocal mechanisms associated with different patterns of vocal fold vibration. She also highlighted the complexity of registration, emphasising that the voice cannot be fully explained by looking at one structure or mechanism in isolation.

The course explored how acoustic relationships contribute to different vocal timbres, including yell and whoop qualities. These terms describe contrasting acoustic configurations: yell quality is typically associated with a stronger, brighter, more brassy sound, while whoop quality tends towards a rounder, smoother and more flute-like tone.

Rather than treating these qualities as fixed categories, understanding their acoustic foundations can help voice teachers and singers explore how changes in vowel shape and vocal tract configuration influence the sound.

The sessions also considered how singers can manage transitions between these qualities to develop a more even tone across their range. This has practical implications for vocal pedagogy, particularly when working with different voice types and musical styles.

What can a spectrogram tell us about the voice?

A particularly practical aspect of the course was the use of spectrograms to visualise vocal sound.

A spectrogram displays the frequency content of a sound over time, allowing us to examine patterns that may not be immediately apparent through listening alone. Gökçe demonstrated how spectrograms can reveal harmonics, formants, vibrato patterns and changes in vocal energy.

Through a range of audio examples, participants explored how different vocal techniques appear visually, including classical singing, contemporary vocal qualities, vocal distortion and overtone singing.

These demonstrations illustrated how spectrograms can help practitioners connect what they hear with the acoustic processes that contribute to the sound. They can also provide useful feedback when tracking a singer’s development or comparing recordings made before and after a teaching intervention.

However, interpreting a spectrogram requires an understanding of what its features represent. A visual pattern does not automatically explain the cause of a particular vocal sound, and different acoustic features may overlap. Gökçe encouraged participants to develop their understanding gradually, using listening, reference materials and experimentation alongside visual analysis.

The aim is not to measure every possible detail, but to identify the information that is genuinely useful for a particular teaching or research question.

Creating reliable recordings for teaching and research

The second part of the course also explored how recording conditions influence the acoustic information we collect.

A recording captures not only the voice itself, but also the effects of the surrounding environment and the equipment used. Room reflections, reverberation, microphone characteristics and recording settings can all affect the resulting sound and its visual representation.

Gökçe explained the differences between sound reflection, absorption and transmission, highlighting how hard surfaces can create reflections while softer, porous materials can absorb more sound. Neither a highly reflective nor a completely acoustically dead room is necessarily ideal for every purpose; the goal is to understand the environment and ensure that it is appropriate for the task.

For voice research, consistency is particularly important. When comparing recordings, using the same microphone placement, room and recording settings helps reduce unwanted variation and makes the results more meaningful.

The course also introduced considerations when selecting microphones and recording formats. For detailed acoustic analysis, an appropriate microphone response, sufficient recording quality and uncompressed formats such as WAV or AIFF can help preserve the information needed for analysis.

These principles are relevant not only to researchers collecting data, but also to voice teachers who want to document progress or use visual feedback in online and in-person lessons.

Bringing vocal acoustics into practice

A key message throughout the two sessions was that acoustic analysis should support, rather than replace, professional judgement.

Gökçe discussed how practitioners can use recordings and visual feedback to explain concepts, investigate specific vocal challenges, document development and support students’ understanding of their own voices. For example, recordings taken at the beginning, middle and end of a teaching period can provide a useful comparison, provided the same repertoire excerpt and recording conditions are used wherever possible.

At the same time, it is important to avoid overinterpreting small differences in a spectrogram or assuming that every visible variation is significant. Acoustic information is most valuable when it is connected to a clear question and considered alongside listening, musical context and the individual needs of the voice user.

For those interested in developing their skills further, experimenting with spectrogram software and listening to recordings with selected frequency ranges filtered out can help build familiarity with the relationship between acoustic features and perceived sound.

Over time, this combination of listening, observation and analysis can make technical concepts more intuitive and easier to apply in practice.

Connecting science and the art of voice

Gökçe Kutsal’s Introduction to Vocal Acoustics for Spoken and Sung Voice demonstrated how scientific understanding can enrich our approach to singing, speaking and voice education.

By exploring the properties of sound, the relationship between harmonics and formants, vocal registration, spectrogram analysis and recording techniques, participants gained an introduction to the tools and concepts that can help make vocal phenomena easier to understand.

Ultimately, vocal acoustics is not about reducing the voice to numbers or graphs. It is about using scientific insight to deepen our understanding of the extraordinary instrument that is the human voice.

Thank you to Gökçe Kutsal for sharing her knowledge and guiding participants through these fascinating concepts across both sessions.