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Clock drift can lead to a desynchronization between clocks over time, and apparently, this clock drift can vary according to the environment/temperature according to this Wikipedia article.

Has anyone recorded variation in clock drift in Soundtraps deployed in different environments (temperatures and/or depths)?

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Our group recently did a four-month deployment of SoundTraps in the northeastern Gulf of Mexico at depths ranging from ~100 to ~450 m. For the few instruments that were still recording when we recovered them (two ST500s and three ST600s), I was able to measure the exact clock offset and thus estimate their clock drifts (based on a linear drift assumption).

All the units were running slow, with drifts of 5.2 an 5.6 s/day for the ST500s and 7.7, 7.6 and 7.7 s/day for the ST600s. When we got back to the lab, I ran a deck test at room temperature on one of the ST500 and recorded a drift of ~1 s/day. Unfortunately, we don't have in-situ temperature measurements but it would be interesting to determine whether these really high drifts are consistent with temperature. Also, it's interesting that the ST600s seem to be experiencing a higher drift that the 500s, which are the older model.

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    $\begingroup$ Ludo, you can find the in-situ temperature measurements in each of the log files. It represents the temperature inside the unit, not the water temperature, but they should be pretty close to each other. $\endgroup$
    – Melissa
    Commented Oct 15, 2022 at 21:15
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    $\begingroup$ We recently tested the drift of the ST600s in our lab at room temperature and also found drifts of about 7-8s/day, for all three devices tested. $\endgroup$
    – DeniseR
    Commented Oct 22, 2022 at 16:17
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I compared the SoundTrap ST4300 clock to a camera system with a very precise RTC. The camera shutter sound could be heard in the acoustic recordings so I compared the time stamp of the images to the time stamp in the acoustic recording. I found that the drift was about 41.5 seconds per day! This was in the kelp forests off San Diego, CA where water temperatures was on average 22 deg C in July 2018.

See Figure S2 in the supplementary material of this paper: https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light

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I expect that like every RTC (real time clock) also the RTC of the soundtrap drifts: a good crystal (20 ppm) may drift up to 10 minutes per year if kept constant at 25 °C.

If the temperature changes the drift increases quadratically in temperature difference from 25 °C (0.04 ppm/°C^2 is typical).

More details can be found in here and here.

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We have observed up to a 15-20 offset in time after 5 month deployments with ST600s. The manufacturer is testing a fix currently to solve this issue, so within a few months, I would expect a firmware update to improve the clock accuracy.

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    $\begingroup$ 15-20 seconds or minutes? $\endgroup$
    – WMXZ
    Commented Apr 20, 2023 at 16:48
  • $\begingroup$ Sorry, 15-20 minutes. This was observed when using Periodic Recordings checked, Record 4 hours every 4 hours. This equates to continuous recordings, but limits each file to be 4 hours in duration. I am not sure if this scheduling affected our observations though. $\endgroup$
    – Timothy Rowell - NOAA Federal
    Commented Apr 24, 2023 at 15:44

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