This week Zoom announced their latest offering Zoom F3 Portable Field Recorder, a 32 bit audio device that features no gain controls. It’s not the first device to offer 32bit Float (floating point audio), Sound Devices and Steinberg also offer this.

So what makes 32bit float so special?

For most professionals 24-bit audio is the standard rate and widely used in both music and post. But 24-bit recording does have some limitations which 32-bit float does away with. It is possible to clip a 24-bit recording. The latest generation of 32-bit audio interfaces are now appearing with NO GAIN CONTROL. The reason for this? The claim that you can neither clip the digital signal or add noise by setting the gain too low. Watch the video below to see more.

In many ways it seems that 32-bit float audio is something that offers so much, however for many 32bit recording is regarded as unnecessary.

We offer two areas of recording where 32-bit float recording is a useful tool in the arsenal of both music and post recording engineers. Both of them come down to one thing… uncontrolled environments.

32-Bit Recording For Live Music

There can be no more uncontrolled recording environment than a live gig. The soundcheck has taken place and you’ve set the gain on your preamps to account allow for enough headroom whilst keeping the noise floor as low as possible.

However, if someone on stage makes a change either to their equipment settings or playing styles then it’s perfectly possible to end up with clipping on the recording. 32bit floating point audio allows the person recording the event to set gains with caution in mind, knowing that any clipping on the recording can be removed in the DAW, or if any elements of the recording had low gain that can be lifted in the DAW with less chance of adding noise floor.

32-Bit Recording For Location Sound

Those who capture live sound on set deserve a medal. Often overlooked in the shoot planning or even worse, seen as an annoyance, location sound can be a tough gig. There’s a lot of fast moving parts and the unexpected can happen at any moment. In some cases the scene can be cowboys whispering threats then gunfire!

Even if you know what to expect, imagine capturing sound as a jet airliner comes into land. The shot starts with the plane half a mile away and ends with the rubber hitting the tarmac. At the start of the shot the sound of the jet is hardly audible but as it hits the tarmac the sound is deafening.

In both scenarios, 32-bit float gives the sound engineer an opportunity to capture the sound with less chance of either clipping or too much noise floor. Having researched for this article, many location engineers were sceptical of the 32-bit float theory to start with, but having created a 32-bit float workflow, said they wouldn’t go back.

Some Words Of Warning

It’s worth pointing out some words of warning for those interested in a 32-bit float recording workflow.

If you are using a conventional capture device that has gain settings for each channel, then it’s still possible to clip the pre-amps. 32-bit float recording just prevents you from clipping the digital recording. In effect it passes the problem of gain staging onto the post stage in the DAW.

Sound Devices has an excellent article on this part of the process and a deeper explanation on the benefits of using a 32-bit workflow.

“Modern, professional DAW software can read 32-bit float files. When a DAW first reads a 32-bit file, signals greater than 0 dBFS may first appear clipped since, by default, files are read in with 0 dB of gain applied. By applying attenuation to the file in the DAW, signals above 0 dBFS can be brought below 0 dBFS, undistorted, and used just like any 24- or 16-bit file.

For 32-bit float recording, exact setting of the trim and fader gain while recording is no longer a worry, from a fidelity standpoint. The recorded levels may appear to be either very low or very high while recording, but they can easily be scaled after recording by the DAW software with no additional noise or distortion. This can be seen with these sample files. This is the same source, one recorded with 24-bit fixed and the other with 32-bit float. Both files appear clipped when initially read into DAW software, but the 32-bit file’s gain can be scaled by the DAW.

Each audio sample for 32-bit float files consumes 32 bits of space on a hard disk or memory, and for a 48 kHz sampling rate, this means that 32 x 48,000 = 1,536,000 bits per second are needed for 32-bit, 48 kHz files. So for 33% more storage space compared to 24-bit files, the dynamic range captured goes from 144 dB up to, essentially, infinite (over 1500 dB). But more importantly, audio signals above 0 dBFS are preserved in the file, rendering clipped audio a thing of the past.

Recording 32-bit float audio files, along with high performance analog and digital electronics that can take advantage of its massive dynamic range, offer sound designers and sound mixers a  new way to record audio. This is especially useful for applications where very loud, unexpected sounds can be captured without the use of limiters. The trade-off for using 32-bit float files is larger file sizes compared to 24-bit files.”

Which leads to our second word of warning… workflow changes when using 32-bit float. Modern DAWs such as Pro Tools, Nuendo, Cubase and Studio One all offer 32-bit float options, but it’s important to make such that anyone involved in the project knows you will be delivering 32-bit float files. In nearly all cases a music engineer is expecting 44.1/24 and a post engineer 48/24. Be clear when working with 32-bit float to communicate with the person working at the end of the food chain, in some cases conversion or pre-mix preparation is going to need to happen.

Other arguments against 32-bit float include the file size increases? Really? In a world of 4k and 8K video specs and with drives costing next to nothing, someone really wants to cite file size as an argument against using 32-bit float?

In summary, for many conventional applications 24bit audio is fit for purpose, but for uncontrolled environments, such as the two examples given above, it is worth considering using 32-bit float for capture.

Are you using 32-bit float for either music or location? What are you thoughts?