Engineers Garage

  • Electronic Projects & Tutorials
    • Electronic Projects
      • Arduino Projects
      • AVR
      • Raspberry pi
      • ESP8266
      • BeagleBone
      • 8051 Microcontroller
      • ARM
      • PIC Microcontroller
      • STM32
    • Tutorials
      • Audio Electronics
      • Battery Management
      • Brainwave
      • Electric Vehicles
      • EMI/EMC/RFI
      • Hardware Filters
      • IoT tutorials
      • Power Tutorials
      • Python
      • Sensors
      • USB
      • VHDL
    • Circuit Design
    • Project Videos
    • Components
  • Articles
    • Tech Articles
    • Insight
    • Invention Stories
    • How to
    • What Is
  • News
    • Electronic Product News
    • Business News
    • Company/Start-up News
    • DIY Reviews
    • Guest Post
  • Forums
    • EDABoard.com
    • Electro-Tech-Online
    • EG Forum Archive
  • DigiKey Store
    • Cables, Wires
    • Connectors, Interconnect
    • Discrete
    • Electromechanical
    • Embedded Computers
    • Enclosures, Hardware, Office
    • Integrated Circuits (ICs)
    • Isolators
    • LED/Optoelectronics
    • Passive
    • Power, Circuit Protection
    • Programmers
    • RF, Wireless
    • Semiconductors
    • Sensors, Transducers
    • Test Products
    • Tools
  • Learn
    • eBooks/Tech Tips
    • Design Guides
    • Learning Center
    • Tech Toolboxes
    • Webinars & Digital Events
  • Resources
    • Digital Issues
    • EE Training Days
    • LEAP Awards
    • Podcasts
    • Webinars / Digital Events
    • White Papers
    • Engineering Diversity & Inclusion
    • DesignFast
  • Guest Post Guidelines
  • Advertise
  • Subscribe

How does the human voice works

By D.Mohankumar April 21, 2008

Most of the sound generated by the human voice organ can be understood by the fellow humans. We produce sound to express emotion, mental imagery, and language. Human voice is the most natural form of communication involved with environmental and situational reality. Actually a spoken word has more meaning than its explanation in the dictionary.


Human voice is produced from the sound generating structures including lungs, larynx, glottis and voice tract. The three important structures are lungs, vocal cords in the larynx or Sound box and the vocal tract. The power source for generating the voice includes lungs, rib cage, diaphragm and abdominal muscles. These structures generate a controlled air stream that passes through the vocal cords. When the air rushes through the glottis (opening of the wind pipe or trachea), the glottis opens and closes and changes the resistance of air continuously. The power source structures are capable of complex adjustments to keep the quality and loudness of the sound.
Larynx
Larynx
 
The vocal cords in the larynx are responsible for the generation of sound. These elatic folds vibrate according to the opening and closing of the glottis. The air stream then passes though the vocal tract act as a resonator for the sound. The vocal tract includes the pharynx, tongue, palatte, oral cavity and the nose. The resonance of these structures determines the quality of the voice produced.
Vocal cords in the larynx
Vocal cords in the larynx
 
Adult men and women have different vocal folds sizes; reflecting the male-female differences in larynx size. Adult male voices are usually lower-pitched and have larger folds. The male vocal folds, are between 17 mm and 25 mm in length. The female vocal folds are between 12.5 mm and 17.5 mm in length.
 
 
[header = Sound Production]
 
The Bernoulli Effect and sound production
The Bernoulli Effect is the reduction of lateral air pressure due to its forward motion. As the air from the lungs passes through the vocal cords, Bernoulli Effect develops in the air. This combines with the elastic property of the vocal cords and causes the vocal cords to shut. When the air pressure below the glottis diminishes, the glottis opens. The excess pressure of air coming from the lungs cause an excess pressure below the glottis and move the vocal cords apart. Due to the Bernoulli Effect, the glottis closes immediately. Due to the difference in the air pressure, the glottis opens again. Thus due to the repetitive and controlled opening and closing of the glottis, a train of air pressure passes into the vocal tract.
 
 
[header = Human Voice Frequency]
 
Frequency of Human voice
The vibratory frequency of the vocal cords fixes the fundamental frequency of the human voice. The pressure of air from the lungs and the flexibility of the vocal cords determine the fundamental human voice frequency. Thinner vocal cords produce high frequency voice. The frequency of sound also depends on the air pressure in the lungs. The complex tone of the voice is set by a number of higher harmonics. The amplitude of these harmonics decreases with the frequency. Typically this decrease is around 12 dB per octave.
 
Resonance and Formant
The vocal tract act as the resonator of the voice. The sound from the vocal tract will have peculiar resonant frequencies rich in relative amplitude and relative loudness. The human vocal tract resonates in different frequency. Usually it shows four or more resonances. The Formant is the term applied to describe the resonant frequencies of the voice tract. Formant is defined by Fant as ‘the spectral peaks of the sound spectrum of the voice. The formants are frequency information characteristics of the voice. The formants change their centre frequency and band width during speech.
 
The fundamental frequency of the resonance depends on the length and shape of the vocal tract. In men the average length of the vocal tract is around 17 centimeters. The frequency of resonance can be determined using the formula
nV / 4L.
n is the positive odd integer, V is the speed of sound in the air and L, the length of the vocal tract. The first four resonant frequencies of male voice range between 500 and 3500 Hz.The formant amplitude is maximum in the glottis and minimum when lips open.
 
 
[header = Male and Female Voices]
 
Male and Female Voices
Male and female voices differ in the fundamental frequency. The fundamental frequency of male voice lies in the range of 85 to 180 Hz while that of the female in the range of 150 to 300 Hz. In terms of the Formants, about five formants are required for male voice while four formats for female voice. The formant frequencies of female are higher than that of the male. The difference is very high in the third and fourth formants and least for the first formant. This is mainly due to the length of the voice tract. Voice tract of the female is shorter than that of the male. The formant frequencies are inversely proportional to the length of the voice tract.
Formants
Formants
 
Voice Pitch
The human voice has many components and is created through a myriad of muscle movements. Pitch is an integral part of the human voice. The pitch of the voice is defined as the “rate of vibration of the vocal folds”. The sound of the voice changes as the rate of vibrations varies. As the number of vibrations per second increases, so does the pitch, meaning the voice would sound higher. Faster rates form higher voices, or higher pitches, while slower rates elicit deeper voices, or lower pitches. The vibrations, and the speed at which they vibrate, are dependent on the length and thickness of the vocal cords, as well as the tightening and relaxation of the muscles surrounding them. This explains why women generally have higher voices than men do; women tend to have higher voices because they have shorter vocal cords. The length and thickness of the vocal cords, however, are not the only factors that affect one’s pitch.

Filed Under: Electronic Projects

 

Next Article

← Previous Article
Next Article →

Questions related to this article?
👉Ask and discuss on Electro-Tech-Online.com and EDAboard.com forums.



Tell Us What You Think!! Cancel reply

You must be logged in to post a comment.

EE TECH TOOLBOX

“ee
Tech Toolbox: 5G Technology
This Tech Toolbox covers the basics of 5G technology plus a story about how engineers designed and built a prototype DSL router mostly from old cellphone parts. Download this first 5G/wired/wireless communications Tech Toolbox to learn more!

EE Learning Center

EE Learning Center
“engineers
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, tools and strategies for EE professionals.

HAVE A QUESTION?

Have a technical question about an article or other engineering questions? Check out our engineering forums EDABoard.com and Electro-Tech-Online.com where you can get those questions asked and answered by your peers!


RSS EDABOARD.com Discussions

  • Finding past posts on edaboard?
  • Industrial Relay Board Design for Motorcycle Use
  • I think i have devised a new type of "super_transformer" for the Electricity grid?
  • What is the purpose of this relay?
  • mosfet driver problem in regeneration mode

RSS Electro-Tech-Online.com Discussions

  • Pic18f25q10 osccon1 settings swordfish basic
  • Sump pit water alarm - Kicad 9
  • Anyone jumped from Easyeda std to Easyeda pro?
  • turbo jet fan - feedback appreciated.
  • More fun with ws2812 this time XC8 and CLC

Featured – LoRa/LoRaWan Series

  • What is the LoRaWAN network and how does it work?
  • Understanding LoRa architecture: nodes, gateways, and servers
  • Revolutionizing RF: LoRa applications and advantages
  • How to build a LoRa gateway using Raspberry Pi
  • How LoRa enables long-range communication
  • How communication works between two LoRa end-node devices

Recent Articles

  • How IoT network topologies work
  • The top five AI startups to watch in 2025
  • STMicroelectronics unveils SoC based on secure MCU
  • Nexperia’s 48 V ESD diodes support higher data rates with ultra-low capacitance design
  • Taoglas releases Patriot antenna with 18 integrated elements covering 600 to 6000 MHz

EE ENGINEERING TRAINING DAYS

engineering

Submit a Guest Post

submit a guest post
Engineers Garage
  • Analog IC TIps
  • Connector Tips
  • Battery Power Tips
  • DesignFast
  • EDABoard Forums
  • EE World Online
  • Electro-Tech-Online Forums
  • EV Engineering
  • Microcontroller Tips
  • Power Electronic Tips
  • Sensor Tips
  • Test and Measurement Tips
  • 5G Technology World
  • Subscribe to our newsletter
  • About Us
  • Contact Us
  • Advertise

Copyright © 2025 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy

Search Engineers Garage

  • Electronic Projects & Tutorials
    • Electronic Projects
      • Arduino Projects
      • AVR
      • Raspberry pi
      • ESP8266
      • BeagleBone
      • 8051 Microcontroller
      • ARM
      • PIC Microcontroller
      • STM32
    • Tutorials
      • Audio Electronics
      • Battery Management
      • Brainwave
      • Electric Vehicles
      • EMI/EMC/RFI
      • Hardware Filters
      • IoT tutorials
      • Power Tutorials
      • Python
      • Sensors
      • USB
      • VHDL
    • Circuit Design
    • Project Videos
    • Components
  • Articles
    • Tech Articles
    • Insight
    • Invention Stories
    • How to
    • What Is
  • News
    • Electronic Product News
    • Business News
    • Company/Start-up News
    • DIY Reviews
    • Guest Post
  • Forums
    • EDABoard.com
    • Electro-Tech-Online
    • EG Forum Archive
  • DigiKey Store
    • Cables, Wires
    • Connectors, Interconnect
    • Discrete
    • Electromechanical
    • Embedded Computers
    • Enclosures, Hardware, Office
    • Integrated Circuits (ICs)
    • Isolators
    • LED/Optoelectronics
    • Passive
    • Power, Circuit Protection
    • Programmers
    • RF, Wireless
    • Semiconductors
    • Sensors, Transducers
    • Test Products
    • Tools
  • Learn
    • eBooks/Tech Tips
    • Design Guides
    • Learning Center
    • Tech Toolboxes
    • Webinars & Digital Events
  • Resources
    • Digital Issues
    • EE Training Days
    • LEAP Awards
    • Podcasts
    • Webinars / Digital Events
    • White Papers
    • Engineering Diversity & Inclusion
    • DesignFast
  • Guest Post Guidelines
  • Advertise
  • Subscribe