Mounting MEMS microphone in housing - sealing gasket, adhesive

[davegravy]

I'm getting my feet wet with MEMS microphones for a personal project and eventually will want to integrate the sensor into a device housing.

A gasket needs to be used between the sound port and the housing. The gasket material and geometry chosen has a significant affect on the acoustic performance since it forms part of the acoustic channel with the housing, and my project is sensitive to this.

I'm looking for advice on how can one practically prototype the sensor-housing interface.

Are there vendors of miniature gaskets that will do small volume orders at reasonable prices? I think I'll be looking for something that's roughly 0.6mm inner diameter, 2mm outer diameter, and less than 0.5mm thick.

I presume some form of adhesive is also typically used to keep the sensor, gasket, and housing bonded together. Any suggestions on what type?

[Kean]

Maybe you can just use a small o-ring inserted into a recess in the adjacent housing?

Edit: You can find kits of mini o-rings intended for waterproof watches on eBay quite cheaply, and run some tests.

[BreakingOhmsLaw]

Read the application note and the general application notes very carefully. I assume you are using ST or Knowles, they both have a lot of literature available on the subject.  A big trap is the design of your accousting aperture. There's a nasty thing called Helmholtz resonance that can ruin your day.
Accoustic calibrators like the venerable Bruel & Kjaer 4231 are really useful - if not indispensable - when designing anything that is remotely precise.

[Benta]

Maybe you can just use a small o-ring inserted into a recess in the adjacent housing?

I second this. O-rings are standard, cheap, easy to source and available in different grades.
Don't reinvent the wheel.

[davegravy]

Read the application note and the general application notes very carefully. I assume you are using ST or Knowles, they both have a lot of literature available on the subject.  A big trap is the design of your accousting aperture. There's a nasty thing called Helmholtz resonance that can ruin your day.
Accoustic calibrators like the venerable Bruel & Kjaer 4231 are really useful - if not indispensable - when designing anything that is remotely precise.

I will be exploring different aperature designs, and impact on freq response with COMSOL but I'm uncertain about feasibility of prototyping and testing these designs without a big budget (which I assume is needed for things like custom cut gaskets).