Self-Taught Designer Uses 1890s Tech to Crack a Problem Audio Engineers Called Impossible, and Sennheiser Noticed

A century-old acoustic trick pushes a basic dynamic driver past anything major brands have ever pulled off.

Making flathead earbuds produce sub-bass frequencies was considered a physical limit by the audio industry, not a problem worth solving.

Valphonics, a self-taught designer in Northern Ireland, didn’t accept that idea. So, he reached back to 1890s physics and older earbud concepts to build something the community thought was impossible.

When he shared his achievement on Reddit, audio engineers and even an iconic audiophile brand started paying attention.

The Problem No One Bothered to Solve

Typical earbuds suffer from acoustic short-circuiting. When the driver moves to create sound, bass frequencies (longer wavelengths, lower energy) simply dissipate before reaching the ear.

It’s like trying to create a strong wind in an open field using a tiny handheld fan.

That’s why frequency response drops fast below ~100Hz. By 50-60Hz, or the range of kick drums and bass guitars, response has fallen off a cliff. Major manufacturers have known this for decades. They considered it a physical limit, not a problem worth solving.

“We’ve had teams of engineers working on earphones for decades, and got nowhere. Not due to inability but due to what was deemed physical limits.” — oratory1990

And with IEMs dominating the market, there was little incentive to chase a problem considered unsolvable.

The Solution: Old Physics, Older Designs, New Trick

Valphonics’ trick isn’t new. He combined Helmholtz resonators, which are principles dating to the 1890s, with the 1990s “pipe earbud” concept from brands like Sony and Aiwa (Head-Fi thread). Then, he built it with modern 3D printing.

It isn’t pure open-earbud magic, but it applies familiar physics in a purpose-built way.

The Caveat

Because Helmholtz tuning relies on controlled air volume behavior, a partial seal helps the system work. Hence, the mandatory foam covers: they create a semi-seal that lets the resonator do its job.

Some purists may argue that this weakens the achievement.

One of those is oratory1990, a pro engineer who has measured 700+ headphones and has been a prominent figure for headphone audiophiles.

Valphonics acknowledged the issue and clarified that the frequency response graph he shared was actually a result of a ‘non-complete seal.’

Still, oratory1990 remained skeptical, so he requested a test unit.

Why Couldn’t the Industry Do This?

Major manufacturers have engineering teams, R&D budgets, and deep institutional knowledge. Sennheiser, for instance, already uses Helmholtz resonators in their IE 900. But, they used it for treble refinement in the 6.5-10kHz range, not bass.

So why didn’t anyone push the same idea into earbud bass? Capability isn’t the issue. Priorities are.

Flatheads are a niche product. IEMs dominate the market. Corporate R&D doesn’t chase problems deemed physically unsolvable when the business case is thin. “Physical limits” became dogma, and dogma doesn’t encourage experimentation.

It’s not that they haven’t tried, though. FiiO’s EM5, for instance, added an “acoustic flute tube” to boost bass. However, reviewers found it lacked the authority and depth of a good in-ear monitor, so it didn’t really grow in popularity.

Valphonics, on the other hand, can iterate without roadmaps or quarterly goals. He can chase a single problem with no corporate pressures.

“I absolutely love flathead earbuds,” the designer has written. “I will forever stand by them as my favourite transducer type.”

He’s also made a few other unique designs in the past, like the Lander and Mascara, which also use vintage designs or technology with a modern twist. Plus, he open-sources his designs after a year.

Then Sennheiser Showed Up

When Valphonics posted the build to Reddit, the thread quickly drew thousands of upvotes and hundreds of comments.

One of which is Sennheiser’s official account with a coy “Like working in project management?!”

Valphonics replied, “If it meant working for Sennheiser I would 100% be down 😀.”

Reddit immediately clocked the irony, with user craterIII quipped, “Sennheiser on the way to steal this man’s IP.”

A German audio giant with nearly eight decades of engineering expertise uses the same Helmholtz technology in their flagship products. They could have solved flathead sub-bass themselves.

Instead, they’re asking a self-taught designer from Northern Ireland if he’d like a job.