How Instructional Audio Overcomes the Top 3 Barriers to Listening   

Students spend three-quarters of their school day listening to the teacher. Even if children can hear the words spoken, they can encounter barriers to learning if they don’t quite understand what those words mean. 

Whereas adults only need to comprehend 50 to 60% of spoken words to understand what’s being said, children need to hear 90 to 100% of spoken words to get all the information they need, as their database of knowledge is still developing. ​Young children between the ages of 6 and 9 have a significantly harder time tracking and distinguishing voices amid background noise than adults, according to a recent study published in the Journal of Neurosciencei.​ 

By using instructional audio systems, educators increase both the audibility and intelligibility of their voices, so every student can hear and understand their instruction.  

Audibility + Intelligibility = Comprehension 

First, it’s important to understand the difference between audibility and intelligibility, and how it affects the listening and learning environments for students.  

  • Audibility refers to whether or not we can hear what is said. 
  • Intelligibility refers to whether or not we comprehend or understand what is said. 

For example, a teacher might speak at a consistent, audible volume at the front of the classroom. However, audibility and intelligibility decreases when she turns to write on the board, or when she moves around the classroom. Add some ambient and background noise into the mix—the hum of the HVAC system or shouting in the hallway—and regardless of how loud the teacher speaks, these additional factors further compromise intelligibility. 

Here are the top three barriers to listening in the classroom and ways schools can use instructional audio technology to boost audibility and intelligibility to support better learning outcomes. 

1. Environmental Barriers to Listening 

Similar to how bright lights and warm temperatures distract students, environmental noise can quickly divert their attention. Common environmental barriers to listening include ambient noise (the whirl of an HVAC unit), reverberation (reflected sounds, such as the echoes of laughter or moving furniture) and learning space design (open classroom environments or learning pods).  

According to the American National Standard for Acoustical Performance Criteria, empty classrooms typically register a background noise of 35 decibels, somewhere between a soft whisper and the hum of a refrigerator. However, when those classrooms include students and teachers, the noise level can quickly skyrocket to 60 decibels (equivalent to normal conversation or the sound of an air conditioner). Particularly lively classrooms can reach up to 90 decibels (the level of noise you’d hear sitting in traffic in a car). 

Even if ambient noise levels are kept to a minimum, room acoustics impact the ways students perceive sound and understand their teachers’ words. For example, sounds like the scrape of a chair or the thud of a book can linger in a room after they first happen (also known as reverberation). These sounds bounce off desks and walls. When many of these sounds reverberate at once, noise levels increase and intelligibility decreases. 

Classroom design, or the ways in which students are taught today—in small groups, rotating through learning stations or learning in open classrooms—also introduce additional noises and interruptions that compete with the teacher’s voice and present environmental barriers to listening. 

​​​By connecting to Lightspeed instructional audio systems, teachers can speak into a lanyard microphone that helps deliver the same listening experience to students—regardless of competing noises. 

2. Physics of Sound and Voice 

In addition to environmental barriers to listening, the barriers related to the physics of sound and voice greatly affect audibility and intelligibility. These include distance (the space between the teacher and the student), directionality and the projection of key sounds. 

Where you sit in a classroom, significantly impacts how you perceive sound. When the distance between the teacher’s voice and a student’s location doubles, sound intensity decreases by 50%. For example, if a classroom is comprised of rows of desks—three, six, and 12 feet away from the teacher—sound intensity will slide from 70 decibels to 58 decibels by the time it reaches the students in the back row.  

Consider these statistics revealed in recent studies: 

  • Students sitting as close as 6 feet from the teacher showed a 17% loss in critical speech recognition.ii 
  • Students sitting at the back of the classroom may miss up to 30% of a teacher’s words.iii 
  • Students who speak English as a second language understood 93% of what a teacher says when sitting 6 feet away, but those sitting 18 feet away only understood 62%. iv 

Another critical component of audibility is directionality—which also affects how well a student can hear her teacher.  For example, if a teacher changes sound direction by walking as she speaks, or turns away from the class, her sound level decreases, as does intelligibility.  

Certain types of sounds can create listening barriers if they are not projected clearly. For instance, there are differences in the ways we say and hear consonants and vowels. It’s easier to project vowels with louder voices, but consonants—particularly soft consonants like “p,” “th” and “sh” can create an intelligibility gap for students.  

Particularly for beginning readers or non-native English speakers, hearing and understanding all these sounds build language acquisition.  With the support of classroom audio, teachers can express nuances in speech, including the differences between soft consonant sounds and blended sounds. At the same time, instructional audio allows them to dynamically teach without  straining their voices. 

3. Physiological Barriers to Listening 

Even in the most carefully designed classroom environments, some students will face physiological barriers to listening. Children with mild or moderate hearing loss, auditory processing disorders, or learning disabilities face even higher stakes in noisy classrooms.  

Because hearing tests may only be given annually or every other year, their educators might not know which of their students are experiencing hearing deficits. 

  • According to The MAARS Project research study, 30% of elementary school students can’t pass a 15-decibel hearing test, primarily due to ear infections. The study concluded that 70 percent of students with mild hearing loss will become academically deficient in at least one subject by the 6th grade if they don’t receive interventions. 
  • According to the American Osteopathic Association, 20% of teens will experience some hearing loss— a rate about 30 percent higher than 20 years ago, largely attributed to the increased use of headphones. 

Teachers are also not immune to physiological barriers that impede student listening. They talk for hours all day, every day, and compete with other noise. Nearly 600,000 teachers in the United States miss at least one day of work per year because of voice problems. At a time when schools nationwide face acute teacher shortages, these absences due to strained vocal cords put additional pressure on school staffing. 

Educators can consistently deliver audible, intelligible lessons to their students with the support of instructional audio. Teachers using these systems audio systems report ease of speaking and greater vocal endurance as well as decreased fatigue, and greater voice clarity.v 

No matter what physiological barriers they face, every child should hear every word from anywhere in the classroom. Instructional audio brings equity to the classroom by ensuring that teachers’ voices can be heard and understood, and that they’re able to connect with their students without raising their voices. 

Lightspeed Instructional Audio Cuts Through the Noise, Delivers Equity and Access 

No classroom will ever be 100% free of noise or distractions, and all students have different needs.  

With the aid of classroom audio technology, educators can overcome environmental, physical and physiological barriers to listening in diverse learning settings.  

To learn more about how instructional audio helps classrooms overcome barriers to listening, download our eBook, Improving Student Learning Through Clear, Intelligible Sound