discussion / Acoustics  / 14 April 2022

Sensor availability in the PRC

My lab has a visiting scholar from China who's interested in potentially conducting acoustic monitoring work once he returns home next year. It seems like most of the major manufacturers have pretty massive markup to ship to the PRC (he's mentioned finding SM4s for 3200USD), so my next recommendation was to find somebody who can do PCB manufacturing and make his own audiomoths but I'm wondering if there are any other options in the Chinese market that anyone is aware of. 

Hi David,

There a quite a few options to buy recorders through either Alibaba or Taobao. They are very cheap and the quality is actually pretty good depending on what kind of work you want to do. They can be powered with USB powerpacks for extended periods.

I would say this would be a good place to start.

Hi David,

I can build him one per requirements.  I'm getting started on the solar powered variant.  If your scholar is in the Beijing area, I can put him in touch with a colleague who does this sort of work.

Jamie's tip piqued my curiosity, so I bought what I thought might be what Jamie was talking about.  It is an SK-001 as detailed here (not my video) for SGD4 or thereabouts.  The price alone boggles the mind, though there are some characteristics that should be borne in mind if used for conservation work.

Foremost is the use of MP3 rather than raw uncompressed WAV which make comparing this data with existing recordings challenging.  Second, an electret condenser mic is used, so manual calibration of recordings may be required  (MEMS mics OTOH have stricter characteristics that are documented).  Third, it is unknown what kind of AGC or signal companding is used (this is in addition to data compression).   Since the device is advertised as a voice recorder, the presence of AGC/companding/noise gate features would not be surprising.  Also, I could not get it to work with a 64G micro SD card, but 32G was ok.

The SK-001 device could be useful for presence/absence type of PAM.  For other work, more testing would be needed to see if this device would be suitable.

Once again, I'm referring only to the SK-001 that I bought that I thought Jamie might be referring to.  These comments may not apply to other low cost recorders.