For a little more scale, a whispering person can be about 20 to 30 dB, while a typical conversation is about 60 dB. A motorcycle passing by would be about 90 dB, and a very loud concert can be in the 110 dB area. Much higher than that and you are entering a range where the sound becomes physically painful. If so, why should any recording equipment go beyond the dynamic 144.5 dB range of 24-bit audio?
Level settings (or not)
The crazy dynamic range of 32-bit floating audio is where the assertion that levels never need to be set comes from, even though this is a little trickier than it sounds. The highest level at which a device can record is called 0 dBFS (here FS means “full scale”). Anything higher than that will be trimmed, which is why it sounds distorted when youtubers shout like that.
Now you usually set the audio levels when you set up your computer to avoid reaching this limit. Setting these levels involves applying gain to the microphone signal, which is an irreversible step that crushes the dynamic range even of 24-bit recording.
“When you’re recording sound on set, you’ll usually apply gain. And some recorders will apply 30 to 90 decibels of gain,” says Pereira. “This is good when you have a quiet scene where two people are whispering. So you can go up the recorder dial to say, more than 60 [decibels]. So now when someone decides to call, between 60 and 145, it’s not very dynamic range. “
In contrast, with 32-bit floating-point recording, there is no need to apply gain before recording. “When you’re recording in a 32-bit format, there’s no volume button, it basically just creates a mathematical graph of data that you can then interpolate in post-production,” says Pereira.
Setting levels on 24-bit systems can be tricky due to ground noise. To put it simply, no matter how quiet your recording space is, there’s always a bit of noise from background objects or even the electronics where you’re recording. Adding gain to the signal during recording will amplify that noise, as well as your audio source, and once it’s incorporated into the recording, it will be there forever.
32-bit floating recordings have more flexibility to make adjustments after the fact (and in some cases can even help with low-noise noise issues). That said, it’s important not to let this give filmmakers and sound producers a false sense of security. “It will not solve the problems inherent in the shooting site. For example, if there is an AC or a strong fan nearby, 32-bit recording will not make that noise go away,” says Pereira.
Managing noise on the set and making sure that the microphones pick up the signal correctly will always be important, but once your computer is set up correctly, having the ability to capture audio even beyond the peak point is a useful tool. belt. But don’t expect to leave 24-bit audio behind forever.
Chain links
So if 32-bit is so great, why not the default? For starters, many steps in production, including editing, mixing, and especially distribution, will use a 24-bit workflow, which means that additional data will be lost at some point. And an audio engineer will need to make adjustments at some point to ensure that the audio signal is not trimmed when the sampling is reduced to 24-bit, as it would be if the levels were not adjusted correctly during initial recording.
Basically, this means that the work that would have been done initially on set is downloaded in post-production. So you have a choice: set the levels correctly on the set and record directly in 24 bits, or record in 32 bits and add the extra step later. One way or another, it’s a step you have to take, and some would say you can do it too when you’re on set.
