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Microphone question ?

in Device Purchase

Hi there, I just discovered your AudioMoth device and I have a question about the microphone.

What is the type of microphone you embedded inside of it ?

Is there a jack input available to use our own microphone ?

Thanks a lot for your answer

Julien

5 comments

5 Comments

julien

Nov 15, 2019

Thanks a lot, Alex.

Do you have a roadmap for the next version ?

We are interested for "data" logging purpose and art.

Alex Rogers

Nov 15, 2019

Hi, We use a Knowles SPM0408LE5H-TB-6 microphone - https://datasheet.octopart.com/SPM0408LE5H-TB-Knowles-Acoustics-datasheet-14433657.pdf.

There isn't a jack on the current version of AudioMoth but the next version will have the mounting footprint to for a 3.5mm jack on the top face so that it can be used with electret microphones and hydrophones. Alex

David Wilson

Dec 17, 2019

Replying to

Hi Alex, it appears that the SPM0408LE5H-TB-6 has been made obsolete by the manufacturer, so it won't be available forever. Knowles are recommending the SPM0687LR5H as a replacement, although the sensitivity and some other specs are very different. Do you have plans to replace the microphone?

Alex Rogers

Dec 17, 2019

Replying to

Yes, we're experimenting with replacement options at the moment. They all have less internal amplification than the the SPM0408LE5H-TB-6, but are effectively the same design, so we're looking at adding an additional pre-amplifier and also seeing if we can reduce the SD card write noise that sometimes appears in the recordings when the batteries are low by using separate linear regulators for the digital and analog parts. Piezo MEMS are also an option but they appear to have a much lower sensitivity at high frequencies so the Knowles replacements are probably what we will opt for.

Jean Weber

Dec 21, 2019

Replying to

Adding an additional pre-amp would be fantastic. I am not in electronics, but I guess that the difficulty could be to get it working with low self-noise and low power consumption. SPM0687LR5H has a noise-floor of 24db instead of 31db for SPM0408LE5H-TB-6 and less distortion (Invensense’s latest ICS-40730 is given for a noise floor of 20db). A well designed additional pre-amp could significantly reduce the noise for more distant recordings.