CIEM build guide
Ear impressions that build a better custom monitor
A custom IEM can only fit as accurately as the impression we receive. For AAW builds, we need a clean, deep, full-shell pair: both ears captured open-mouth, past the second bend, with enough concha and helix detail for a stable seal.
Before the appointment
Start with a clean, professional impression session
Have your impressions taken by an audiologist or a trained professional. Do not attempt a DIY impression. The clinician should inspect the ear canal first, confirm it is safe to proceed, place an otoblock correctly, and use medical-grade silicone impression material suitable for deep ear impressions.
For CIEM work, the jaw position matters. Use a bite block and keep your mouth open naturally while the material is injected and while it cures. This helps account for canal movement when you sing, speak, chew, or perform on stage, reducing the chance of a seal that works only when your jaw is still.
Bring this requirement to your audiologist
Please request full-shell, open-mouth impressions for custom in-ear monitors, with canal extension beyond the second bend and complete concha/helix coverage.
Coverage map
What the impression must capture
The ear canal should be long enough to pass the second bend and preserve the natural direction of the canal. The outer ear must not be a shallow surface print; it should include the full concha bowl, helix lock, crus, tragus, anti-tragus, and the surrounding concha edge with usable thickness.
That outer-ear detail gives our shell designers the landmarks needed to model a CIEM that seats consistently, distributes pressure evenly, and stays secure without over-tightening the canal.
- Canal is smooth, complete, and extended beyond the second bend.
- Concha bowl is filled with enough material to show its edge clearly.
- Helix and tragus areas are present, not thin or collapsed.
- No air bubbles, drag lines, torn tips, folds, or missing surfaces.
Good reference
A quality pair from four inspection angles
A good pair should look complete from every side. The canal stalks should be long and smooth, the concha should hold enough body, and the outer-ear features should remain clear when viewed from the front, back, top, and bottom.
During the session
How to get the pair right the first time
These are the practical details that most often determine whether a pair can go straight into production or needs to be retaken.
Stabilize the jaw
Use a bite block and keep the jaw open until the material is fully cured. Do both ears with the same jaw posture so left and right behave consistently when worn.
Place the otoblock deep and safely
The audiologist should position the otoblock beyond the second bend when appropriate for the ear, after inspection. Leave the otoblock attached when sending the impression.
Inject slowly from deep to shallow
The material should fill the canal first, then the concha and helix area, without trapping air. A steady injection prevents bubbles, folds, and weak thin spots.
Wait for a full cure
Removing the impression too early can bend the canal stalk or tear fine landmarks. After removal, the clinician should inspect both your ear and the impression.
Retake warning signs
Common reasons impressions are not usable
If you see any of these patterns, ask for a retake before shipping. A remake at the impression stage is much faster than a refit after the CIEM is built.
Send to AAW
Pack the pair so the shape survives the trip
Once both impressions pass inspection, let them fully cure, label left and right, and pack them in a crush-resistant box. Do not trim the canal, shave the concha, remove the otoblock, or force both impressions into a small container.
Include your order number and contact details. If your audiologist provides a professional 3D scan, send the STL or HPS files to AAW support and keep the physical impressions until we confirm the files are accepted.
Shipping address
Advanced AcousticWerkes #01-03, LHK2 Building76 Playfair Road
Singapore 367996
Attn: CIEM Department
Tel: +65 8731 5476
The best refit is the one you never need.
Give the lab a complete, deep, clean pair of impressions and the finished CIEM starts with a better chance of sealing naturally, staying comfortable, and sounding like the model you auditioned.