When a Small Geometric Change Solved a Big Audio Problem

In product development, performance improvements are often associated with new electronics, better sensors, or more sophisticated algorithms.

Occasionally, however, the solution comes from something much simpler.

A few millimeters of geometry.

During the development of one of our wearable tracking devices, we encountered an issue that initially appeared to be related to microphone performance. The device incorporated an onboard microphone intended to capture environmental audio while remaining protected within a sealed enclosure.

On paper, the microphone met all requirements.

In practice, the captured audio did not.

The investigation that followed became a reminder that acoustics, much like structural mechanics, are heavily influenced by the physical environment surrounding a component.

The Problem Wasn't the Microphone

The tracker consisted of an internal microphone mounted within a protective enclosure.

Like many wearable devices, the enclosure was designed primarily around requirements such as:

• Durability
• Environmental protection
• Manufacturability
• Assembly simplicity
• User comfort

While these objectives were achieved successfully, testing revealed that audio quality was not meeting expectations.

Sounds that were clearly audible outside the device appeared noticeably attenuated once recorded through the enclosure.

Initial investigations focused on:

• Microphone sensitivity
• Firmware settings
• Signal processing
• Mounting conditions

Yet none of these areas explained the performance loss.

The microphone itself was functioning correctly.

The enclosure was not.

Understanding Acoustic Shadowing

Sound travels as pressure waves through air.

For a microphone to accurately capture those waves, the sound must be able to reach the sensing element with minimal obstruction.

Inside the enclosure, the microphone sat beneath a protective cover. Although openings existed for sound transmission, the geometry surrounding the microphone was unintentionally interfering with the incoming acoustic energy.

Rather than providing a direct path to the microphone, the enclosure geometry created a situation where sound waves encountered surfaces, cavities, and obstructions before reaching the sensing element.

The result was similar to trying to listen through a partially blocked opening.

The microphone could still hear, but it was no longer hearing efficiently.

Looking at the Problem as a Mechanical System

Instead of approaching the issue as an electronics problem, we began treating it as an acoustic and mechanical problem.

The question became:

"How can we provide a cleaner and more direct path between the external sound source and the microphone?"

The answer was surprisingly straightforward.

Rather than relying on a flat opening above the microphone, we introduced a conical tunnel extending from the enclosure opening directly toward the microphone inlet.

Why a Conical Tunnel Works

At first glance, the feature appeared insignificant.

It was simply a tapered passage connecting the external opening to the microphone location.

However, the geometry fundamentally changed how sound entered the enclosure.

The conical shape provided several advantages.

Improved Acoustic Directionality

The tunnel created a more direct path for incoming sound waves.

Instead of allowing sound energy to disperse throughout the enclosure volume before reaching the microphone, the geometry guided acoustic energy toward the sensing element.

More of the incoming sound reached the microphone with fewer reflections and losses.

Reduced Acoustic Obstruction

Without a defined pathway, portions of the enclosure effectively acted as barriers between the sound source and the microphone.

The conical feature reduced these obstructions by creating a dedicated acoustic channel.

This minimized the amount of sound energy being blocked, scattered, or redirected away from the microphone.

Better Coupling Between Environment and Sensor

Microphones perform best when they can interact directly with pressure variations in the surrounding air.

The tunnel improved the acoustic coupling between the external environment and the microphone inlet.

In simple terms, it allowed the microphone to "see" more of the sound that existed outside the enclosure.

Controlled Sound Entry

The tapered geometry also helped create a smoother transition between the external opening and the microphone location.

Rather than forcing sound through abrupt changes in cross-sectional area, the conical shape encouraged a more gradual flow of acoustic energy toward the sensor.

The Results

After implementing the conical extension, audio testing immediately demonstrated noticeable improvement.

Recordings exhibited:

• Higher clarity
• Improved sound pickup
• Reduced attenuation
• Better overall intelligibility

Most importantly, the improvement was achieved without:

• Changing the microphone
• Modifying firmware
• Increasing power consumption
• Adding new electronics

The solution was entirely mechanical.

A small geometric feature transformed the acoustic performance of the device.

The Broader Engineering aspect

This experience reinforced an important principle that extends far beyond acoustics.

Components do not operate in isolation.

A microphone's performance depends not only on its specifications but also on the geometry surrounding it.

A sensor's accuracy depends not only on its electronics but also on how it is mounted.

A structure's strength depends not only on material properties but also on load paths and constraints.

In every case, the environment around the component can be just as important as the component itself.

Engineering Often Happens Between Disciplines

What made this solution particularly interesting was that it sat at the intersection of multiple engineering domains.

The problem appeared electrical.

The root cause was acoustic.

The solution was mechanical.

These cross-disciplinary challenges are often where the most effective design improvements emerge.

In this case, a simple conical tunnel provided a direct acoustic pathway to the microphone, improving sound capture without increasing complexity elsewhere in the system.

Sometimes the best engineering solutions are not about adding more technology.

They are about creating a better path for existing technology to do its job.

How This Thinking Shapes Development at Hoomanely

At Hoomanely, we see this kind of problem-solving as a core part of building better products for pets and the people who care for them. Real-world performance is rarely determined by a single component alone. A microphone, sensor, antenna, or battery can only perform as well as the environment around it allows.

That is why we pay close attention to the details that are easy to overlook: enclosure geometry, component placement, acoustic pathways, airflow, sealing, and how a device behaves once it leaves the lab and enters everyday use. Often, the most meaningful improvements do not come from adding complexity, but from refining the physical design so existing technology can perform at its best.

The conical tunnel in this device is a small feature, but it reflects a larger engineering mindset we value at Hoomanely. Thoughtful mechanical design can unlock better performance, improve reliability, and create a better experience without changing the core technology itself.

For us, that is what good product development looks like: solving real problems with careful engineering, attention to detail, and a deep understanding of how products behave in the hands—and on the pets—of the people who use them.