32-bit float files – A New Era?

Two major manufacturers of recording equipment developed in 2019 both new recorders able to record not only 16 and 24 bit files, but a jump up to32 bit float files. These recorders (three from Sound Devices called MixPre II and three from Zoom, the F6, F3 and F2) are as most equipment not meant for birders, but musicians, podcasters and videographers. In 2021 the Zoom F2 came with mono Plug-in-power input and 15h batterylife in 2 AAA’s the size of 2 matchboxes! And in 2022 an F3 with connection for 2 XLR’s and up 1Tb SD-micro card creates possibilities for quality recording for days. There is even an updated F8n if more inputs are needed. So why should birders and bird recordists bother about this new technology?
See also: ZOOM F6 Setup for birders

SD MixPre3 II in Zoom F4 bag

The great advantage is the high dynamic range making it almost impossible to destroy a recording, since whatever level above 0 dB recorded could be normalized down to below 0 dB and worked further in post. I struggle a bit with Audacity as it only has limited amount of dB to be reduced, but Adobe Audition is great for this task as you can do it in several steps till the results are good. So, my suggestion for a workflow is to lower the volume (normalize input) in Audition till below 0 dB and then save the file as Wav in 32 bit or 24 bit. Then it is easy to open it in Audacity for further treatment with High Pass Filter for low 500 Hz rumble and if necessary, Noise reduction f.ex. 5 dB.
In practical terms out in field this means you can turn the input knob to nearly full gain all the time, not to be worried of blowing the files and then concentrate on the bird(s) in front of you. Rest is work at home on the computer. This will probably for many of you sound like really bad habits during fieldwork, but since the files now can not be destroyed by neglect or just birds screaming/singing/calling much loader than anticipated the only sensible thing to do is to get it all documented into the SD-card! You can even increase sounds far away, but then of course you so amplify surrounding sounds/white noise etc. as well.
Have a look here for further explanation of the workflow and the results of this new era in bird recording. See also page on Filters in Audacity

Blue Tit recorded with full gain (left) and then normalized to 0 db. The left part of the recording is completely distorted before treatment in Adobe Audition reducing the level – 25dB or more.
Great tit (Wav-file) in Audacity and then saved as Mp3, listen to result below
Great tit Parus major, Tromsø Norway 32 bit floating file to Mp3 in Audacity
Blue tit edited and saved as Mp3.
Common Shelduck female calling
Greenfinch singing from a treetop.


Since the new recorders were put in sale, the testing of the files and comments has now appeared, in the XC-community comments were added:

Setup of Zoom F6 for birders
32-bit float explained