discussion / Acoustic Monitoring  / 20 April 2021

Recommendations for a waterproof microphone for bats and birds?

Hey all. I'm drawing up the specs for an at-sea recorder, geared towards recording migratory bats and birds. We're going to likely be using some of the Wildlife Acoustics (WA) bat minis, but we will have like 20+ stations, so are looking into AudioMoths as a cheaper yet reliable alternative.

However, most mics for these units are 'weather-resistant' rather than waterproof. Meaning they can withstand the rain, but not being dunked underwater (which is a reasonable event that may happen to some of our units). WA does make a waterproof design, but it is expensive (SMM-U2). I've also stumbled onto Dodotronics Momimic, but they have zero specs on their page. Has anyone used one before?

We are looking for something with at least an IP57 rating. Straight up hydrophones are not a good alternative, as the recording quality would be negatively impacted. We are open to potting some mics ourselves, but would prefer an off the shelf alternative.

Thanks for your advice in advance!

You may want to consider enclosing the mic in an IP57 enclsoure with a cutout covered by an ePTFE membrane. ePTFE membranes are breathable membranes rated to be waterproof to 10m depth. You may want to do some testing though as well. ePTFE are the membranes that cover mics and speakers on waterproof smart phones. If you can't locate any, let us know. We have a few of them in stock.


Hi Emily,

As an addendum to Akiba's excellent suggestion, if you're at the planning stage, you may consider contracting out the construction of a custom waterproof microphone and possibly housing, to interface with the recording unit of your choice.  The Vesper VM1000 has an impressive video but to my knowledge has not been used in conservation work (meaning your publications may face extra scrutiny).  I'm considering using this mic in a recorder I'm building, but any one of us will be able to put together a board to interface with your recorder.

There are a few waterproof lavalier mics out there that you can press into service as well, but I would consider this the expensive option.

I didn't see this post until the digest came out, but if you still need some comments...

I suggest asking this question on one of the sound recordists forums.  The people on [email protected] are generally quite knowledgeable on microphones and protecting them...and quite friendly :)   Ivano Pelicella (Dodotronics) monitors that forum and will happy to chime in if you have a question on their mics.  Or you can email him.

Regarding the Momimic...it uses the Knowles FG23629, but I see what you mean about the lack of much specs.  This is their datasheet, if you don't have it - https://www.digikey.com/en/products/detail/knowles/FG-23629-D65/810005

The Momimic seems like a good choice for what you described and it's off the shelf, although I haven't used it personally.  Maybe email Ivano for some help.

Good luck!  I hope you will be posting your progress and results!