Acoustic foams and dust meshes for smart speakers
Acoustic foam combined with dust mesh helps smart speakers maintain a stable tone over time, reducing reverberation inside the enclosure and keeping dust off the speaker diaphragm throughout the product's lifetime.
Smart speakers are usually placed permanently in living rooms, bedrooms or kitchens, where there is fine dust, cooking oil vapor and fluctuating humidity. After a year or two without suitable protective materials, the sound can become muddier and the microphones less sensitive. Getting the design right from the start helps avoid these complaints.
Moreover, the microphone array of a smart speaker must pick up voices from a distance. Dust in the microphone port reducing sensitivity by just a few decibels is enough to noticeably impair the voice assistant's command recognition.
The role of acoustic foam in the enclosure
Inside the enclosure, sound waves from the back of the diaphragm reflect back and forth between the walls, creating unwanted resonance. Open-cell foams such as polyether polyurethane or melamine absorb part of this energy, tightening the bass and reducing boominess.
Foam density, thickness and placement directly affect the result. Foam that is too thick can reduce the effective volume of the enclosure; foam that is too thin absorbs poorly at frequencies below 500 Hz.
Dust mesh: acoustically open yet dustproof
Dust mesh uses polyester mesh fabric or ePTFE membrane mounted in front of the speaker diaphragm and microphone ports. The core requirement is low acoustic impedance, meaning sound passes through with almost no loss, while still blocking dust particles.
- Monofilament mesh fabric: acoustic impedance of 10–50 Rayl, suitable for large speaker openings.
- ePTFE membrane: good water and dust resistance, suitable for microphone ports.
- Mesh with pre-applied adhesive border: quick to apply, precise positioning.
Many design teams only measure sound when the product is new. We recommend also measuring after dust and humidity testing, because that is the condition users will actually hear for years. — Application Engineer, AMS Vietnam
Combining two materials in one part
A growing trend is to pre-laminate the dust mesh onto foam and double-sided tape into a single part. This approach reduces assembly steps, minimizes positioning errors and makes quality control easier. AMS can convert laminated parts to drawing, with cutting tolerances suitable for automated lines.
When choosing foam for smart speakers, it is also important to consider UL 94 HF-1 or HBF flame ratings since the speakers are plugged in continuously, as well as low volatile organic compound emissions so the product has no odor when unboxed. Melamine foam is light and highly flame resistant but more brittle, while polyether PU foam offers better tear strength and is easier to process.
Contact AMS Vietnam to receive acoustic foam and dust mesh samples, along with a proposed laminate structure for your speaker product.
