3 Approaches To Echolocation Mechanics

This article describes three progressively complex ways echolocators interpret sound, surfaces, and space; ranging from simple reflective techniques to advanced reverse-engineering approaches used in noisy environments.

Exploring Basic Echolocation Approach

Most common technique echolocators use can be explained in this basic flowchart. Strong sounds are represented as Blue, Echoes are represented as green and events/objects in the environment are represented as orange.

 With this basic echolocation approach, there are three primary and three secondary variables. The primary variables are highlighted as orange on the above diagram and discussed here:

1. The Listener: what the listener physically and/or cognitively chooses to do, will impact the way information is received and perceived. For example, body Language; facing the source of sound or source of echo etc. 

2. The Sound Created: The listener has many options of kinds of sounds available and their delivery. Both things affect the desired results.

3. The Surface: When a sound bounces off a surface and creates an echo, it imparts a lot of information about the physical surface structure, influencing where the echo is directed towards etc.

The three secondary variables and the arrows representing how sound travels to the listener, here are their detailed descriptions. Although these secondary variables aren’t always consciously perceived, they are essential for building predictions and interpreting echoes accurately.

4. Reflected Echo: When an echo reaches the listener, the spatial information available is connecting the relationship between the three primary variables and that information is contained primarily within a reflected echo and that signal is what's perceived by the listener.

5. Emitted Sound: This is the path sound waves created are travelling towards the surface. The distance between the sound created and the surface it will bounce off will affect the information available if it varies between uses. This path of sound is present but imperceptible to the listener.

6. Received Sound: Similar principles of the variable of Emitted Sound is also applied to the Received Sound, but this is the path sounds created takes that is perceptible to the echolocator. A received sound contains some acoustic information the echo will also contain, this auditory information is different from the received sound's spatial information. This gives the user a predictive “fingerprint” of what to listen for in an echo to expect to arrive momentarily later. In practice, the received sound acts like a reference signal, allowing the listener to recognise and compare what changes once the echo returns.(Time Delays Note: Variables of timing between making a sound and hearing a sound affect how you cognitively process the time delay between a Received Sound and a Received echo. Most echolocators create sounds that are either made by their body or immediate surroundings, creating an unperceived time delay, allowing the time delay between a Received Sound and a Received echo to be a primary source of distance information)

Spatial echolocation information requires a minimum of all six variables to be present for echolocation to happen in its most basic approach and technique.

Exploring Complex Echolocation Approach

Some echolocators have trained themselves to be sensitive to the most sensitive echoes that they can cognitively perceive if they're in the right environment. These extra variables may carry far less acoustic energy than reflected echoes, sometimes by an order of magnitude or more depending on the environment.

 By choosing to use a complex echolocation approach, it requires extra patience and practice. Most times the auditory signals of complex variables are too quiet to be perceived unless you're in an environment that is already quiet. Here I would like to share some basics about these two extra variables.

Absorbed Echo

 A major reason people use echolocation and apply this complex approach is because, if surfaces didn't absorb a little bit of sound and reflect a lot, then your entire hearing functioning would cease to operate. And since you receive auditory signals by the inner ear absorbing some energy, you're able to perceive all this information still even if most sound is reflected back out of your ear as an Otoacoustic emission. It's a physical function of surfaces reflecting sound waves that shouldn't be ignored by the experienced echolocator as it equally affects the previously discussed “Reflected Echo” and the “Emitted Echo” which is discussed below.

 In short, absorbed echoes carry information about what a surface is made of, not just where it is.

Emitted Echo

 Emitted sound may be a fraction of the energy and information as a reflected wave, but unlike a typical echo, containing all the usual spatial information. This echo contains information about the material inside the surface, its inner structure and density. A real world example of this “emitted echo” being apparent is how bells resonate and ring. If they did not release energy as an emitted echo, then a ringing bell would never make a perceptible sound. You can read more about this effect and optimising it for echolocation in our article Complex Sound Mechanics

 In short, Emitted echoes reveal how a surface releases stored energy over time, offering insight into internal structure and material properties.

Advanced Echolocation Approach

A Reverse Engineering Approach to Echolocation

 This flowchart represents all information used and discovered while using a reverse engineering approach to using echolocation in a loud and sensory over-stimulating environment. Newly introduced variables and information to focus on, that aren’t a focus on simpler echolocation techniques, have been highlighted as orange. The amount of information contained in this approach is advanced and requires detailed explanation of all elements and processes. This will be explored in a future article.

 This approach is included here for conceptual completeness rather than immediate practice, and is most relevant in loud, complex environments.