<p>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 <strong>41.5 seconds per day</strong>! This was in the kelp forests off San Diego, CA where water temperatures was on average 22 deg C in July 2018.</p>
<p>See Figure S2 in the supplementary material of this paper: <a href="https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light" rel="noreferrer">https://tos.org/oceanography/article/an-optical-imaging-system-for-capturing-images-in-low-light-aquatic-habitats-using-only-ambient-light</a></p>

CC BY-SA 4.0
2022-10-11T23:27:58.047Z
2022-10-11T23:27:58.047Z
Camille Pagniello
<p>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.</p>
<p>If the temperature changes the drift increases quadratically in temperature difference from 25 °C (0.04 ppm/°C^2 is typical).</p>
<p>More details can be found in <a href="https://www.edn.com/rtc-design-part-1-real-time-clocks-still-matter-in-automation-iot-applications/" rel="nofollow noreferrer">here</a> and <a href="https://www.edn.com/rtc-design-part-2-temperature-compensation-is-critical/" rel="nofollow noreferrer">here</a>.</p>

CC BY-SA 4.0
2022-10-07T19:23:11.687Z
2022-10-08T07:18:14.960Z
2022-10-08T07:18:14.960Z
WMXZ
<p>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.</p>

CC BY-SA 4.0
2023-04-20T16:48:18.930Z
15-20 seconds or minutes?
WMXZ
CC BY-SA 4.0
2023-04-24T15:44:38.303Z
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.
Timothy Rowell - NOAA Federal
CC BY-SA 4.0
2023-04-20T13:59:21.143Z
2023-04-20T13:59:21.143Z
Timothy Rowell - NOAA Federal
<p>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).</p>
<p>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.</p>

CC BY-SA 4.0
2022-10-15T21:15:14.480Z
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.
Melissa 
CC BY-SA 4.0
2022-10-22T16:17:17.790Z
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.
DeniseR
CC BY-SA 4.0
2022-10-08T12:59:11.743Z
2022-10-08T12:59:11.743Z
Ludo Tenorio
<p>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 <a href="https://en.wikipedia.org/wiki/Clock_drift" rel="noreferrer">Wikipedia article</a>.</p>
<p>Has anyone recorded variation in clock drift in Soundtraps deployed in different environments (temperatures and/or depths)?</p>

<soundtrap>
Does the Soundtrap clock drift vary in different environments (temperature)?
# Does the Soundtrap clock drift vary in different environments (temperature)?

(Asked by: username_0 on 2022-10-07)

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](https://en.wikipedia.org/wiki/Clock_drift).

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

**Tags:** soundtrap


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## 4 answers

### Answer by username_4 on 2022-10-08. Score: 6 | Accepted answer

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.

> **Comments:**
> **username_5**: username_4, 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.  
> **username_6**: 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.  

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### Answer by username_1 on 2022-10-11. Score: 7

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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### Answer by username_2 on 2022-10-07. Score: 4

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](https://www.edn.com/rtc-design-part-1-real-time-clocks-still-matter-in-automation-iot-applications/) and [here](https://www.edn.com/rtc-design-part-2-temperature-compensation-is-critical/).


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### Answer by username_3 on 2023-04-20. Score: 1

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.

> **Comments:**
> **username_2**: 15-20 seconds or minutes?  
> **username_3**: 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.  

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