New Echolocation Research Published at the University of Southampton

From a new study published by the University of Southampton:

The results showed that both sighted and blind people with good hearing, even if completely inexperienced with echolocation, showed the potential to use echoes to tell where objects are.

It is great to see this type of research being done to help aid the visually impaired community. When this type of thing has been studied in the past it is often to the benefit of science in general or discreet facets of the biology industry. Here we have a team of researchers dedicated to providing this information to help the blind mobility community and add more scientific framework to a mobility tool in need of this type of verification.

Researchers from the University of Southampton's Institute of Sound and Vibration Research (ISVR) and University of Cyprus conducted a series of experiments with sighted and blind human listeners, using a 'virtual auditory space' technique, to investigate the effects of the distance and orientation of a reflective object on ability to identify the right-versus-left position of the object. They used sounds with different bandwidths and durations (from 10-400 milliseconds) as well as various audio manipulations to investigate which aspects of the sounds were important. The virtual auditory space, which was created in ISVR's anechoic chamber, allowed researchers to remove positional clues unrelated to echoes, such as footsteps and the placement of an object, and to manipulate the sounds in ways that wouldn't be possible otherwise (e.g. get rid of the emission and present the echo only).

Read the rest of the article here:
http://www.southampton.ac.uk/engineering/news/2013/05/20_echolocation.page

Access the full report here:
http://www.sciencedirect.com/science/article/pii/S0378595513000737

VIDEO: What is Echolocation?

I recently put this video together to spread the word of echolocation to those who need more information.  It provides a clear cut, simple explanation of exactly what it is and how it's used.

If you are still unsure of what echolocation is, I'm sure this video will clear things up.  If you're still skeptical of echolocation, that's alright!  That just means you have the ability to think critically which will inevitably help you learn.

As always if you have any questions or comments feel free to leave them below or contact me directly.

Does the same noise sound the same to two different people?

Well that is indeed quite a question. After all, different people tend to react differently to a given stimulus. One person may find a specific stimulus annoying or even outright disturbing can be both soothing and relaxing to another as it depends largely on the culture and upbringing of said persons. For instance, in many cultures, black has been widely associated with ideas like death and evil while in Japan and other North Asian cultures, they use white to symbolize death instead. That is why one kind of sound may symbolize two radically different ideas for two people depending on their culture. A bell tolling may mean a wedding for one person, but might actually be an alarm to another.

Also, take note that a person’s ear structure also figures largely with how one actually hears and perceives sound. While there are animals in the animal kingdom that only possess exposed eardrums to receive and process noise, humans have the distinct ear shape with the rest of the more important faculties placed within the head proper. This is so that noise hits the structures and is channeled into the eardrum instead of just letting random noise from all directions that can be found in more primitive animals. Also of note is the fact that the position of ears can also differ from person to person, leading one to perceive noise differently from others. The sensitivity of ears is also another significant factor and some are more likely to perceive subtle vibrations than others.

What are Sound Reflectors?

Have you ever attended an orchestra or an indoor concert? Did you notice anything particularly in your general surroundings? Well, if you didn’t, then perhaps you’ll take note of the way the sound seems to be more solid and seems to reverberate in your bones while in the concert hall as opposed to what you’ll hear in an open-space concert. If you’re wondering what makes it all possible, then the explanation is rather simple. They make use of what are called Sound Reflectors which are relatively simple structures that are placed into the walls to make the musical piece reflect back towards the audience, giving it a fuller and louder effect.

So what are sound reflectors, really? Well, they are simply panels of wood that have been carved into a convex shape that will allow them to reflect sound directly into the audience in order to hear whatever is on stage with even greater clarity. Composed mainly of plywood with some gel to make them even more reflective of sound, this is what makes indoor concerts, lectures and seminars successful thanks to the way that sound is carried and distributed. This is what makes sound reflectors also a must in so many establishments like lecture halls, auditoriums and places of worship.

So next time you attend a huge public gathering such as a seminar or concert and are just wondering how they make sound travel and reverberate throughout the space without making use of any additional speakers, take note and look up as they are probably making use of sound reflectors.

Sound Mirrors Used During Wartime

World War II gave us many advances in technology, but one of the lesser known things that is directly related to echolocation is the “Sound Mirror” At first they seem baffling and quite strange to uninitiated onlookers, but when you understand what they were used for and how they work it's really quite simple yet quite remarkable.

Rising a good twenty feet off the ground and composed of concrete somewhere near the Greatstone Lakes, these structures that highly resemble some kind of ancient wonder built by a prehistoric kingdom are collectively known as Acoustic Mirrors, Concrete Dishes, Listening Ears and, of course, Sound Mirrors. And no, contrary to whatever impressions come to mind they were most assuredly not objects of worship, they were actually built by the British government in conjunction with the military so as to provide an early warning system against enemy air-strikes. Riddled with microphones and other listening equipment, the sound mirrors provided people with a 15 minute warning ahead of time in the event of an enemy attack. Simple but very effective, this allowed Britain and its citizens time enough to evacuate while anti-aircraft weapons are prepared for the eventual arrival of the enemy.

The interesting part here is to note that these are objects designed for sound to bounce off of them.  There aren't too many objects like that.  They acted to focus a small amount of sound energy (over the area of the face of the 30' dish) into a focal point, just like a radio telescope of satellite TV dish.  Somewhere in the center of the dish is where all of the sound would be focused.  If you were to put your head in that central focal point, which is where the microphones would have been placed, you would be able to hear all of the sounds coming into the dish.

An interesting concept when it comes to picturing how echolocation works!

Sensory overlap in humans

A recent email from a reader got me thinking about sensory overlap.  We have these five wonderful senses that we generally think are each doing their own thing to provide us with information.  But a lot of them can be considered to "overlap" in their functionality.  Of course the first case is echolocation.  We can perceive the things around us with our eyes, but we can also perceive things around us with our ears, as we are all learning.  Here are a few things that we perceive with more than one sense.  Feel free to list others you can think of in the comments.

Perceive objects around us:
Vision
Hearing
Touch (only arms length away)

Perceive texture:
Touch
Hearing (not as detailed)
Sight (sometimes deceiving due to color)

Perceive sounds:
Hearing
Touch (vibrations and impulses only)

Perceive flavor:
Taste
Smell

This is just a short list, I'm sure there are more.  What do you think?

Resonant Frequency of a Room

The resonant frequency of a room is a concept often discussed in acoustic design, such as the layout of an auditorium or music studio.  It could also be a topic of discussion when installing a home stereo system.

Essentially, most rooms are rectangular or square, meaning that they have parallel walls across from each other.  These parallel walls make it possible for sound waves to get "trapped" or resonate back and forth between one wall and the other.  Like the infinite image you might see if you look into a mirror and also have a mirror behind you.  And it starts getting really interesting when you realize that there are  particular frequency sound waves that "match" the size of the room.

For example, if a room measures 11.3 feet wide in one direction, that means that a 50Hz tone will bounce perfectly back and forth through the room.  Since the pressure wave continually peaks at the same point in the room it will amplify that frequency in that location.

No, you probably won't actively use this concept during echolocation, but, yet again, an interesting little side note about how sound works and some of the effects you might encounter on a daily basis while practicing active echolocation.