Two acoustic architectures, two approaches

Since 2018 we have delivered 20,000 pairs of one-piece chambers for a six-driver balanced-armature series, while another product line uses clear resin to make internal structure part of the exterior. Below are the problems, the approaches taken and the results achieved.

Client A · six-driver balanced armature Client B · custom in-ear 20,000+ pairs of chambers Since 2018
Case A: six-driver one-piece chamber Many components, tight space, unibody appearance to preserve Case B: clear chambers and internal colouring Left/right consistency, surface quality and colouring
CASE A

Six-driver balanced-armature earphone

One-piece chamber + labyrinth low-frequency tube

Since 2018 6 drivers Labyrinth sound tube Seamless unibody chamber
20,000 pairsChambers delivered for this series
80.2 mmLow-frequency labyrinth tube length
≈90%Assembly efficiency gain vs. cast-mould process
1 stepBonding steps during assembly

Problems to solve

  • 1The earphone uses six balanced-armature drivers plus a crossover board and resistors, so internal space is tight.
  • 2The product positioning requires the unibody look, so the shell cannot be split into multiple parts for easier assembly.
  • 3Conventional cast-mould processes pre-assemble drivers and tubes with many bonding steps, leaving consistency dependent on operator feel.

What we did

  • 1One-piece chamber: driver mounts and sound tubes integrate directly into the chamber, with multi-angle mounting to raise space efficiency.
  • 2Seamless face: no seams on the front of the chamber, preserving the unibody look.
  • 3Clear skin-friendly resin: yellowing-resistant and highly transparent, leaving room for the later diamond-cut faceplate.
  • 4Labyrinth tubes: three tubes of different lengths and bores arranged around the chamber, with an 80.2 mm low-frequency tube in a labyrinth layout.
Six-driver balanced-armature earphone
Six drivers and a tuning switch in a one-piece chamber
Multi-angle driver assembly inside the chamber
Multi-angle mounting maximises internal space utilisation
Three sound tubes and a low-frequency acoustic path
Three sound tubes arranged around the chamber, low-frequency tube in a labyrinth
Seamless front of a one-piece chamber
One-piece forming leaves no seams on the chamber face

Reviewing the project, the partner noted that integrated service support let the product move from design straight into rapid sampling and production, speeding up both B2B programmes and consumer product updates — and that the absence of any visible seam on the chamber face is the most tangible result.

— Client product lead, from the project interview
CASE B

Custom in-ear earphones

Clear chambers, left/right consistency and internal colouring

2 models 3 colours Convective venting Anatomical chamber
2Models delivered (four- and six-driver versions)
3 coloursGlacier Blue · Highland Green · Violet
2 piecesLeft and right chambers modelled separately, delivered as a pair
0 casesReported contact discomfort from the client

Problems to solve

  • 1Left/right chamber consistency was critical. Previous suppliers showed noticeable layer lines that directly affected the finished look.
  • 2Surface finishing had to be fine enough for close inspection of texture and colour — “functional” was not enough.
  • 3Internal driver arrangement needed more design freedom, while fit had to stay comfortable with no discomfort from contact parts.

What we did

  • 1High-resolution DLP combined with a fine post-processing sequence controls layer lines and keeps left/right chambers consistent in dimension and feel.
  • 2Internal colouring: colour is set inside the shell while the outer layer stays clear, avoiding wear-induced fading on the exterior.
  • 3Convective venting improves in-ear pressure, making sound more open and long wear more comfortable.
Clear chamber of a custom in-ear monitor
Clear-chamber custom in-ear · internal structure becomes part of the exterior
Three internally coloured earphone shells
Glacier Blue / Highland Green / Violet: colour set from inside the shell
Fit and shape details of a custom in-ear monitor
Ergonomic chamber: conforms to the ear, spreading pressure over long wear

In the project interview the client said the decision came down to chamber accuracy, stable left/right consistency and fine surface finishing with almost no layer-line issues; both models received good fit feedback with no reports of irritation.

— Client marketing lead, from the project interview

At the client's request, brand names, model numbers and personal names are anonymised. Technical data comes from publicly available partner material and images are used under licence; specific parameters and capacity are subject to project-specific evaluation.

Your product can start with a feasibility assessment

Send structural drawings or ear-impression data and we will provide material recommendations, a process plan and a quote — assessment and revision advice are free.

Fill in the enquiry form View hearables solutions