Thursday, November 4, 2021

Review of The M500 and U384 USB Microphones from Pettersson Elektronik

Review of The M500 and U384 USB Microphones from Pettersson Elektronik

I actually wrote a review of The M500 USB Mic from Pettersson once before, exactly 5 years ago. It may be seen Here

What we'll be doing here, is having another (closer) look at The M500 - As well as the (newer) U384 USB microphone - Also by Pettersson Elektronik

Whenever ordering a bat detector from Pettersson Elektronik (in Sweden), you can always expect it to arrive very well packaged. In my experience, it's always been with the Pettersson / Batsound logo tape sealing the box.

These (USB-based) bat detectors, record the ultrasonic sounds of bats directly onto the device they are attached to. This is done in full spectrum; using various sample rates (kHz) depending on the model you select - As follows:

  • M500 - 500kHz

  • M500 - 384kHz

  • U384 - 384kHz

  • U256 - 256kHz


The M500's; require Windows, and BatSound Touch software to function. In other words, the computing device used with it, must have a Windows-based operating system. Android-based devices are not compatible (at time of this writing).


The M500-384 for example, is much more flexible: It may be used with all operating systems, and a variety of Apps.

In regards to the size and weight of these - The M500 or M500-384 - 43 x 114 x 13 mm (including microphone horn) 

Weight - 60 Grams

List price (directly from Pettersson) is £295 GBP / €343 Eur / $406 US (for either The M500, or The M500-384).


These USB-based bat detectors may be ordered from NHBS (in UK):

Or directly from Pettersson (in Sweden).

There are other wildlife monitoring equipment dealers who stock it as well, and there's probably one in the country where you reside.  


What exactly is The M500 USB Microphone?


  • It is an advanced, ultrasonic microphone, designed to record ultrasounds directly to the device it is attached to. In the case of the M500: This may be a tablet, smartphone, or laptop PC. 

    I found The M500 easy to use: Plug it into the tablet (or laptop) you’re using, launch the BatSound software, and click ‘Record’. The software retains it’s settings from the last time it was used.


  • Using laptop(s) proved to be an excellent arrangement for unattended recording of bats. Either for several hours - or in some cases, overnight - Laptop settings must be looked at / changed (to ensure it doesn't go to "sleep", turn off hard drives, etc.).


I have thoroughly tested The M500 on: Several types/brands of laptops; and several types of tablets - Without major issues.

It performed as one might expect: Issues such as Apps freezing, were eliminated, by closing additional Apps running in the background.

If you are planning to use a bat recorder situated on/near a window or windowsill - In other words, a stationary position: Then The M500 is actually ideal. This is exactly how I used it, when testing one for the (original) review. It worked very well in this capacity.


The M500 is provided with a removable cone, which helps it become more directional; as well as providing protection to the microphone element itself.

M500 with Directional Horn, and USB cable attached.

After installing The Batsound Touch software on a Windows-based tablet, The M500 proved fun and effective in use.



It produced excellent, clear recordings (and spectrograms) of bats. 

It also possessed excellent sensitivity and pick-up range.

I found that attaching a small foam windscreen (the type designed for lavalier mics) over the mic (both with, and without cone) reduced wind & background noise nicely. Most importantly - I determined that these small foam windscreens did not interfere with the recording of bat vocalizations. They may be found quite easily (and inexpensively) online; from various sources.

I’d experimented with several ways of attaching The M500 to tablets: Including double-sided foam tape, and Velcro (“hook and loop fasteners”) - Which worked quite well.


For those who will be recording bats while on the go, The U256/U384 will likely be better suited. They simply plug-in to a handheld smart device (phone or tablet) and you're ready to move.

Below, is a look at what you get when you open the outer box (directly from Pettersson). 



Unpacking of The U384 Microphone from Pettersson: 



The U384 USB Microphone with included accessories

If your device doesn’t have a USB Micro B jack, a simple/inexpensive adapter will get you operational.

BatSound software from Pettersson Elektronik (being installed).
Once again (as in years past) I’ve found BatSound to be a wonderful, sound analysis application. Producing Professional results. I have much more to learn about it...
Many Professionals around the world who work with bats, are quite fond of this piece of software. Further evidence of this can easily be seen whenever you pick up a book dealing with bat bioacoustics. See this book as just one an example.


The U384 USB Microphone’s Bat Recordings on BatSound



The U384 USB Microphone from Pettersson 

The U384 has a built-in cone as part of it’s design. (Photo from Pettersson Elektronik)



U384 - 43 x 35 x 13 mm (including microphone horn) 

Weight - 25 Grams. List price for The U384 Mic (directly from Pettersson) is £259 GBP. From NHBS (in UK) £299.17 


It is constructed of Aluminum with a flat black finish: Lightweight and sturdy. 

What exactly is The U384 USB Microphone? 
  • It is also an advanced, ultrasonic microphone, designed to record ultrasounds directly to the device it is attached to.
(in the case of The U384: This may be a tablet or smartphone)
  • It covers 1 kHz - 192 kHz, records in 384 kHz/16 bit format, and features an Anti-aliasing filter.

I have tested The U384 on: Several types and brands of tablets with zero issues.

I like the fact that it’s frequency range begins at 1 kHz (rather than 10 kHz) which allows me to record all kinds of interesting creatures! (mainly, singing insects).


I've found this USB microphone a joy to use - It’s sensitive, and produces very clean/accurate spectrograms (regardless of the software you use to analyse your recordings).  


So, what's it like to use The U384 Microphone?


Well, it is smaller & lighter than The M500; and transforms your device into a very capable bat detector in an instant. 

The U384 Mic is very easy to use! Plug the module into your device’s USB port, launch the App (of your choice), and you are monitoring/recording bats. 


The U384 requires less current than The M500 units, which translates to longer battery life / operation in the field. The U384 uses a MEMS microphone element; as opposed to the electret type used on The M500 Mics. 


This provides higher sensitivity, and a lower overall noise level. I’ve experienced this firsthand: In use, The U384 is remarkably quiet (the same goes for The U256 USB Mic). BatSound software is a very capable analysis platform. 

Happy bat detecting!

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