Hi, I work in a conservation organization, and we're looking to monitor noise from a nearby (20 meters away), very low, 20-40 hz analysis of bass/vibrations. I was recommended to use the UA-004-64 logger, made by Onset Instruments, white paper attached. Does anyone have any experience with this issue, and would this be a good choice for recording very low bass/vibrations? Cheers, Nikhil
3 February 2025 2:32pm
A geophone-based sensor might be the best choice for this range of frequencies. The Raspberry Shake platform might work well for you:
Professional grade seismograph and infrasound monitors - Raspberry Shake
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8 February 2025 5:43am
According to the white paper that you linked, this HOBO unit is suitable for recording vibrations (not necessarily noise in air) in the 20Hz-40Hz range, but just barely. See page 11, "Dynamic acceleration". Also, while recording at the necessary 100 samples/second, which is apparently the maximum capable, there is memory for only a few minutes of data. See Plot A.
13 February 2025 12:17pm
@Thomas, @ Harold, thanks a lot for your feedback. Clearly there appears to be no cutting back in costing if quality is to be expected. I was hoping for cheaper solutions, but to record at a professional quality level looks like we have to go in for the more expensive options. Thanks again, best regads, Nik.
13 February 2025 3:34pm
You can hack a 6-inch underwater speaker onto a recording unit, and swap it from being speaker to a microphone. They are, on paper, the same thing. That frequency range doesn't work will with small piezo surface (itty microphones). If you want to get fancy, you can add the resistors and capacitors to make a band-pass filter, so you don't pick up quite as much thunder and passing vehicles.
This is a fairly standard audio problem that a good audio engineer can assist with.
I've detected low frequency bird wingbeats with some low-power analog wizardry in the past. But you will need dedicated audio engineering time.
Thomas Blanford