Forum Posts

Robert Manzano
Jun 15, 2021
In Device Support
Hi all, After months of using AM for fieldwork I've noticed some of them create audio files with 0kb. Usually they do it (but not all of them do it) when battery voltage is approaching the 3'6V. But a few do it regardless the battery level. Have anyone come across this issue and the reason of it? Many thanks,
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Robert Manzano
Mar 02, 2021
In Device Support
Hi everyone, Here I share the first results from the comparative test we carried out to see differences in terms of performance on bats between recording devices and membranes. The tested devices were: 1- Audiomoth v1.1.0 (old version) 2- Audiomoth v1.2.0 (new version) 3- SM4 + U1 microphone (x2) 4- SM4 + U2 microphone Furthermore, each version of Audiomoth were set with 3 different membranes plus a fourth one with no casing: 1- Akustikstoff: https://www.akustikstoff.com/Buy-Cuts-of-Speaker-Cloth-in-Various-Sizes/Acoustic-Cloth-2-0-Pre-cut-50-x-160-cm-19-7-x-61-42-Colours::764.html 2- Hydrophobous fabric (TNT), similar to the light fabric used in dinning tables: (in Spanish) http://www.tejidonotejido.com/es/caracteristicas-tejido-no-tejido/ 3- Metal sticker (PP): (in Spanish) https://www.apli.com/es/producto/10066 The devices were placed in a window facing an urban area, at the same angle an elevation. All AM with membranes were using the same type of case. All devices recorded for 4h from 1h after sunset on the 16th of February 2021. The new AM v1.2.0 detected less batpasses (fragments of 5s with at least 1 bat call) and calls (individual pulses) in all four membrane configurations, with different results depending on the membrane used. Differences in batpasses ranged between 8% less (no case) and 43% less (PP membrane). When looking at species level, these values changed, only showing similar results in the commonest species the Kuhl's Pipistrelle. Much scarcer species like Common and Soprano Pipistrelle showed different results, showing much better performance on the former one compared to old AM v1.1.0 in all membrane configurations. Regarding membranes, the Akoustikstoff and TNT showed similar results, having 18-21% less batpasses with the new AM v1.2.0 than the no casing configuration. The PP showed very poor performance. Surprisingly, comparing the AM with SM4, both showed similar results in terms of batpasses, which is the usual variable used in bat ecology studies. I'm waiting for more detailed analysis from other tests done with the same devices, but the results so far point towards the following conclusions: 1- The new AM version has a worse performance in medium freq. bats (pipistrelles) than the old AM version. I think having worse numbers in all 4 membrane configurations is consistent enough to conclude this. The different results when looking at scarcer species might be due to low sample size. 2- The TNT membrane offers a good alternative to the Akoustikstoff membrane. 3- The AM may not be as bad as it seems compared to SM4 when analysing batpasses, at least for medium freq bats. Has anyone done any similar testing, especially regarding old vs new AM version? Or could anyone explain the difference in performance between species? Cheers, Robert
Old vs new vs SM4 (and membranes) comparison content media
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Robert Manzano
Sep 07, 2020
In Device Support
Hi everybody, Does anyone also have the feeling Audiomoth's files' sonograms look less well defined (blurred in Raven, pixelated in Audacity) than other devices? We've been using it for nocmig and comparing to many recordings from Xeno-Canto, ours done with Audiomoth are definitely less defined. Could it be something related to the number of bits the recordings are created with? Many thanks, Rob
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Robert Manzano
Apr 27, 2020
In Flashing support
Hi all, I'm trying to update my Audiomoth's firmware to 1.3.0 (currently using 1.2.1). I downloaded the Flash App and followed the instructions to manually switch to flash mode but I end up with a "No AudioMoth found" status at the end of the instructions, after both leds go off using the paperclip: The steps I follow are the following: 1- Set the switch to CUSTOM 2- Remove the 3 batt's (both led's are flashing) 3- Connect the PROGRAM contacts with a paperclip until led's go off 4- The instructions show No AudioMoth found on the current status. It's also said verify connection For some reason, I hear the usb disconnection sound on my laptop a few seconds after I get to step 4 and leds start flashing again. I'm using Windows 8 64 bits. Any ideas what is causing this problem? Many thanks in advance, Rob
Audiomoth won't get into flash mode content media
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Robert Manzano
Apr 09, 2020
In Configuration Support
Hi all, I've recently been using Audiomoth for nocturnal bird migration sampling in Spain and I was surprised to catch bat calls at unusual very low frequencies (5kHz or lower) with a sampling rate of 44kHz or less. Attach to this message you can find some examples. Having in mind bats usually call >20kHz (except for the bigger Noctules -10-20kHz- and the European Free-tailed Bat-usually around 10kHz-), those bat calls should not be there. They sound like they were sampled using a frequency division detector and some of them are probably Soprano Pipistrelle, which I have every night flying around home and sing 10x higher in freq. (usually 50-55kHz). Other Audiomoth users I know have also experienced this. I've tried to find a possible explanation for this. Perhaps Audiomoth "mixes" configuration parameters and those calls are actually sampled at a higher rate but displayed as if they were sampled in a lower rate? Have any of you come across this matter? Many thanks in advance, Robert Manzano
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Robert Manzano
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