Voiceprint University

Spectrogram

The Spectrogram is a graphical plot of the sound frequency spectrum of the speaking or singing voice. This view shows a time history of the voice spectrum with frequency as the vertical axis, time as the horizontal axis, and the strength of the harmonic components is indicated by the color or intensity of the plot at each point. This Narrowband spectrogram is a display of frequency versus time that resolves the audio spectrum into its individual harmonic components. The audio waveform signal is represented by an amplitude versus time strip at the top of the spectrogram display.

Spectrogram View

The Spectrogram is a time-based display that shows how the frequencies in your voice change over time. This Narrowband spectrogram is a display of frequency versus time that resolves the audio spectrum into its individual harmonic components. The audio waveform signal is represented by an amplitude versus time strip at the top of the spectrogram display.

Unlike the power spectrum, which shows a single “snapshot” of frequency energy, the spectrogram provides a continuous picture of your voice as it unfolds.

• Horizontal axis (X-axis): Time, moving from left to right as you sustain, speak, or sing.

• Vertical axis (Y-axis): Frequency, from low to high.

• Color or shading: Intensity (power) of each frequency. Darker or brighter areas represent stronger energy, while lighter areas represent weaker energy.

In simple terms, the spectrogram answers the question: “How do the frequencies of my voice change moment by moment?”

This display is especially useful for observing:

• Pitch patterns: Fundamental Frequency (F0) and Harmonics appear as horizontal lines, making it easy to see pitch and intonation.

• Formant movement: Tracking resonant frequencies as vowels or vocal tract shapes shift will appear as changes in the shading on the spectrogram.

Power Spectrum View

The Power Spectrum is an instantaneous plot of the audio spectrum showing intensity or power of the signal spectrum versus frequency. Relative intensity level in dB SPL is shown on the vertical axis, and frequency in Hz is shown on the horizontal axis. The power spectrum shows these components as peaks and valleys that form an overall spectral slope or shape that can be viewed easily with resonance analysis on.

• Horizontal axis (X-axis): Frequency, measured in Hertz (Hz), from low to high pitches.

• Vertical axis (Y-axis): Intensity (power) of each frequency, showing how strong or weak each frequency component is.

In simple terms, the power spectrum answers the question: “Which frequencies are present in the sound, and how much energy does each one have?”

This display is especially useful for analyzing:

• Formants (resonant frequencies): Peaks that correspond to resonances of the vocal tract.

• Harmonics: Regularly spaced frequency components created by vocal fold vibration.

• Voice quality differences: For example, a bright or “ringing” sound often has more energy in higher frequencies, while a darker or breathier sound shows more energy in lower frequencies.

Pitch

The Pitch Trace feature displays real-time vocal pitch on both a piano keyboard widget and a pitch spectrum graph in Hz. As you phonate, your pitch is visually mapped to exact piano keys and frequency patterns, making it easy to monitor accuracy, range, and transitions. This dual display enhances pitch awareness and precision, supporting both visual and auditory learning in voice training.

Pitch Plot (Hz)

The Pitch view shows the fundamental frequency (F0) of the voice over time, measured in Hertz (Hz). This pitch trace tracks how high or low your voice is, making pitch patterns easy to visualize.

• Horizontal axis (X-axis): Time in seconds.
• Vertical axis (Y-axis): Frequency, measured in Hertz. Lower values correspond to lower pitches, while higher values correspond to higher pitches.

The Pitch Graph helps you observe:

• Steadiness of pitch: Whether a note is held consistently or varies in frequency.

• Pitch glides and transitions: Rising, falling, or sliding movements across time.

• Vibrato and tremor: Small, regular fluctuations in frequency.

Pitch Piano Widget

The Piano Widget provides a musical reference alongside the Pitch Graph. As you phonate, the widget highlights the corresponding musical note on a virtual piano keyboard.

• Each piano key is linked to a frequency (Hz), allowing you to see the relationship between frequency in Hz and musical pitch (note names like C4, A4, etc.).

• When the voice produces a pitch, the nearest piano key lights up, giving immediate feedback on intonation and note matching.

The Piano Widget helps you:

• Match your voice to musical notes for singing and training.

• Understand the connection between frequency and pitch names.

• Visualize pitch accuracy when aiming for specific target notes.

Together, the Pitch Trace and Piano Widget provide complementary perspectives: the pitch trace plot shows precise frequency changes over time, while the piano offers a direct musical context. Pitch View provides a clear record of pitch accuracy, stability, and flexibility, which is useful for both speaking and singing voice training.

Pitch Settings

Frequency markers corresponding to pitch can be set to practice pitch and intonation exercises.

Loudness

The Loudness view feature provides real-time visual feedback on vocal intensity through a loudness meter widget and loudness trace in dBSPL. As you produce sound, your vocal intensity is tracked and displayed, allowing precise monitoring of volume consistency, contrast, and control. These visual plots will help to develop balanced loudness across pitch and phrase, reinforcing healthy vocal effort and expressive dynamics.

Loudness View (dB SPL)

The Loudness Trace shows how the volume of your voice changes over time, measured in decibels Sound Pressure Level (dB SPL).

• Horizontal axis (X-axis): Time, showing loudness changes moment by moment.

• Vertical axis (Y-axis): Loudness, measured in dB SPL. Higher values indicate stronger vocal intensity, while lower values indicate softer sounds.

The Loudness Graph helps you observe:

• Dynamic range: The difference between soft and loud parts of your voice.

• Consistency of volume: Whether your loudness remains steady or fluctuates.

• Control of intensity: Smooth increases (crescendo), decreases (decrescendo), or sudden changes in volume.

This graph gives a clear record of how effectively you manage vocal power across tasks.

Loudness Meter Widget

The Loudness Meter Widget provides a real-time indicator of vocal intensity, displayed as a speedometer. As the arrow moves left to right the loudness of your voice changes from soft to loud.

• The meter shows instantaneous loudness in dB SPL, allowing you to monitor your voice volume as you produce sound.

• It provides immediate feedback on whether your loudness is within a desired range (e.g., soft speaking, conversational level, or projected singing).

The Loudness Meter helps you:

• Train consistent loudness levels for healthy voice use.

• Practice dynamic control for expressive performance.

• Avoid excessive vocal strain by keeping loudness within safe ranges.

Together, the Loudness Graph and Loudness Meter provide detailed and immediate visualizations of vocal intensity, supporting both vocal training and vocal health monitoring.

Loudness Settings

SPL target lines can be set at specific levels to practice exercises for loudness control.

Brightness

Brightness in the Estill Voiceprint is defined as a change in resonance resulting from changes in the shape of the epilarynx, or the vocal tract area above the vocal folds (filter). Actively narrowing this epilaryngeal space creates a bright tone quality some people describe as twangy, piercing, or ringy. Others describe this sound as “nasal” but we now know that this “ringing” tone can be produced through the nose (nasal) or through the mouth (oral). This sound is bright due to an increase in high frequency sound energy between 2.5 – 3.5 kHz. This spectral band-width is the range of the “singer’s formant” and is said to put the “ring” in the singing voice. Practice producing as bright a voice as you can by cackling like a witch or quacking like a duck. Have fun with these sounds – they should never cause an itch, tickle, or scratch.

The Brightness view provides real-time visual feedback on ring or brightness of the voice through a loudness display widget and dynamic trace graph in dB SPL. As you produce sound, your vocal intensity is tracked and displayed, allowing precise monitoring of volume consistency, contrast, and control. These visual plots will help to develop balanced loudness across pitch and phrase, reinforcing healthy vocal effort and expressive dynamics.

Brightness View

The Brightness Power Ratio measures the amount of sound energy in the 2-4 kHz frequency band by comparing it with the amount of energy in the 0-1 kHz band. This ratio is associated with brightness and carrying power in the voice. In the spectrogram, the Brightness frequency range is highlighted between horizontal green lines. The default setting is 2-4 kHz but this region can be changed in Brightness Settings.

• As you phonate, the program calculates the relative energy in this frequency band.

• This measurement provides direct feedback on how much “brightness” is present in your sound.

• By focusing on this band, you can monitor and train resonance strategies that increase projection and clarity without excessive loudness.

Brightness Meter Widget

The Brightness Meter provides a simple visual indicator of bright energy in the voice:

• The column rises and falls in real time as the brightness increases or decreases.

• A horizontal marker line inside the meter shows the target Brightness Level, that can be assigned in settings.

• If needed, you can restore the defaults by choosing Reset → OK in Change Settings.

The Thermometer Widget helps you:

• See when you are meeting or exceeding your target level of brightness power.

• Monitor Estill Twang Quality consistency across different voice qualities.

• Train safe, efficient vocal projection by balancing brightness with loudness.

Together, the Brightness spectrogram and Meter provide both detailed acoustic analysis, immediate visual feedback on acoustic output power of your voice, and useful tools for developing resonance strategies and healthy voice projection.

Brightness Settings

Brightness Frequency Ranges–Input the lower and upper Frequency to be used in the Brightness Power Ratio measures. Start with 2000 – 4000 Hz.

Brightness Level Target – Set a Brightness Power Ratio for you and your clients.

Sensitivity Level – Move the sensitivity levels from 1 – 99 until the meter responds to your levels of brightness.

Clarity

This exercise is presented with a frequency versus time spectrogram on the left side of the screen. A clear vocal tone will display with strong and clear harmonic traces; a pressed tone will have fewer and or irregular traces with the scattered dots of noise. On the right side of the screen is a Harmonic Level meter with a circular display reporting the harmonic to noise ratio of the sound tracings visible onscreen. As the vocal tone becomes clearer, the blue circle expands indicating stronger harmonics and less noise; as the voice becomes pressed, the blue circle shrinks and may disappear entirely indicating weak harmonics and strong noise.

Clarity Measure

The Clarity Measure looks at how clear or noisy the voice sounds by examining its harmonic structure — the repeating, musical parts of the sound created by vocal fold vibration.

• A clear voice has strong, regular harmonics that show up as clean lines on the spectrogram.

• A less clear voice (pressed, breathy, or rough) has weaker harmonics and more scattered noise throughout the spectrum.

Behind the scenes, the program uses a technique called cepstral analysis to separate harmonics (the “ring” or “tone” of the voice) from noise. The key measurement is called the Cepstral Peak Prominence (CPP):

• High CPP = strong harmonics and clear voice quality.

• Low CPP = weaker harmonics and more noise in the signal.

This measure gives you a reliable score of how clear your voice is at any moment.

Clarity Ball Widget

On the right side of the screen, the Clarity Ball Widget gives an easy-to-read visual summary of this measurement:

• The blue ball grows larger when your voice is clear and harmonic-rich.

• The blue ball shrinks or disappears when your voice becomes noisy or pressed.

This simple display turns complex acoustic analysis into real-time, intuitive feedback. The larger the ball, the clearer your voice.

Together, the Clarity Measure and Clarity Ball Widget help you connect what you see, hear, and feel in your voice. They show not only whether your tone is clear, but also how small adjustments in your technique can improve clarity and efficiency.

Clarity Ball Settings

-The Clarity Level Target can be set from 1 – 100% in order to provide a target for you and clients during training..

Resonance Analysis Plotting

The Resonance Analysis Plot overlays a resonance trace/line (formant indicators F1, F2, F3, …) on top of the narrowband voiceprint or power spectrum so you can see how vocal tract resonances relate to pitch and harmonics in real time.

What the resonance traces mean:

• The green resonance trace is a line that denotes the center frequency of each resonance band (formant) on the Spectrogram. These center frequencies are estimated from a wideband spectrum analysis.
• The green overlay on the Power Spectrum traces the shape, or spectral slope, of the resonances (formants).

Ask a question or leave feedback