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24 -bit vs. 32-bit float audio recording

27 Jun 2024

32-bit float audio is similar to 16- and 24-bit standards, but it works a little differently.

Under a 32-bit float, a much wider range of audio values can be recorded. Vastly more than if there were simply eight new bits to play with.

16-bit audio is capable of recording sound with a dynamic range of up to 96.3 decibels.

24-bit audio recordings can capture a dynamic range of up to 144.5 dB. Meanwhile,

32-bit float audio can capture the absolutely ludicrous range of up to 1,528 dB. That’s not only massively beyond the scope of 24-bit audio, but it’s beyond the scale of what even counts as a sound on Earth.

As Audiophiles, we lean toward the extremes: lower distortion, greater dynamic range, lower noise, higher resolution.

The main difference between 24-bit and 32-bit digital audio is the level of precision or resolution in the audio data. A 24-bit audio sample can represent up to 16.7 million levels of amplitude, while a 32-bit audio sample can represent over 4.2 billion levels of amplitude. A 32-bit digital audio recording can capture a greater dynamic range than a 24-bit recording.

This means a 32-bit digital audio recording can capture a greater dynamic range than a 24-bit recording.

The dynamic range of a 24-bit digital audio signal is about 144 dB, while 32 dB weighs in at 192 dB.

A full symphony orchestra has a dynamic range of about 100 dB. This means the quietest parts of an orchestra are around 30 dB or so, while the loudest parts inch up to 130 dB. A typical conversation at normal speaking volume is around 60 dB, while a rock concert can be as loud as 120 to 130 dB. So a 144 dB is more than sufficient to cover this range. (The dynamic range of human hearing is typically considered to be around 120 dB).

So, if 32-bit is so great, why isn’t it the default? For starters, many steps of production–including editing, mixing, and especially distribution–will use a 24-bit workflow, which means that extra data will be lost at some point. And an audio engineer at some stage will need to make adjustments to ensure that the audio signal doesn’t get clipped when downsampling to 24-bit, the same as it would if levels weren’t set properly during the initial recording.

Essentially, this means that the work that would’ve been done initially on set gets offloaded to post-production. So, you have a choice: Either set levels properly on set and record directly in 24-bit, or record in 32-bit and add the extra step later. One way or another, it’s a step you’ll have to do, and some would argue that you may as well do it when you’re on set.