When you’re learning audio theory, everything seems to be easy, but once you get into practice, things change. Now you devote more time to audio repair than to anything else. You get recordings and begin to process them. You eventually learn how to cope with (or avoid) problems and move on.
Take the noise floor for example: isn’t it unpleasant when your recordings include an unwelcome humming? But do you really understand what it is, where it originates, and how it impacts your work and music?
Do you know how to avoid it, more importantly? If you have any of these questions, you’ve come to the correct spot.
What is Noise Floor?
In a word, the noise floor is the amount of background noise detected in a recorded file. When there is no other auditory signal present, that noise is typically the easiest to identify.
When it comes to noise level, remember that the lower the noise level, the better. But don’t panic; this is a frequent problem, even among music professionals who have meticulously set up a home recording studio. Because almost everything may produce a noise floor, there isn’t much you can do to avoid it in most situations.
Everything may be picked up in your recordings, from computer fans to outside noise, microphones, and even the preamp itself.
Scales used to measure it
The noise floor may be measured in a variety of methods; let’s start with digital systems, which utilize the dBFS (Decibels, Full Scale) scale. The dBFS scale is used to quantify the loudness of recorded audio, and we use a value of 0 dBFS to represent the loudest sound that could be caught. The values of the meter will move from 0 dBFS to -10, -20, -30, and so on as the sound intensity drops (gets quieter). The dBFS scale is often used to measure input or output signals in your soundcard’s (digital audio) converter stage.
A sound pressure level (SPL) meter is another tool for determining the noise floor. It uses a dB SPL scale (akin to the dB scale) to measure sound and is often used in studios to monitor ambient noise.
For starters, when your preamp strength is set to maximum and nothing is connected to the input, you may readily identify noise floor in audio interfaces. In the periphery, it’s the same. In a nutshell, it has to do with circuit noise and the quality of the components you’re utilizing.
To help us better comprehend and examine the topic. The audio bit depth you’re utilizing limits the noise floor in recordings. Which implies it can’t get much quieter. Because of the bit depth’s dynamic range restriction. Take, for example, the following values:
- 16bits = -96dBFS
- 24bits = -144dBFS.
- each bit = 6db of dynamic range
However, due to electronic noise inside the device and within the measuring system, you will always have higher values in practice.
What effect does it have on the recording and final audio quality?
We’ve established a few things thus far. Most importantly (and this should always be said), the lower the noise floor, the better. And when I say noise floor, I’m referring to any unwanted noises on the recordings. So, why is it so essential to keep noise to a minimum? Please bear with me; I’ll get there. I’ll mention a few problems that noise floors may create below:
- It may be difficult to use dynamic plugins or peripherals;
- Because the signal to noise ratio (SNR) is too low, it may be difficult to establish the compressor threshold.
- When employing limiters, this may cause problems. When you restrict and crank up the make up gain, they will increase all low sounds (noise included) as a whole.
Dither vs. noise floor: what’s the difference?
I assume you have a decent understanding of what the noise floor is at this time. So far, we’ve seen a lot of information on what it does, how to measure it, and so on… But, contrary to popular belief, dither is not the same as noise floor.
Your computer will handle audio at a very high resolution when you’re working within a digital audio workstation. That resolution is typically in 32-bit floating point in modern DAWs. You must now decrease that audio file in order to burn it on a CD, for example. Quantization error occurs if the signal’s resolution is reduced to either 24-bit or 16-bit (a.k.a quantization noise). As a consequence of the shift in resolution, you get that noise.
While you aim to lower the noise level, dithering works in the other way. You really introduce noise throughout the dithering process. It may seem backwards, but bear with me while I explain.
If done properly, adding noise to this process may provide a nice final product. In fact, if done correctly, you may not even realize it’s there.
To sum up, we may conclude that quantisation problems are considerably less of a concern today. And if you’re concerned about using dither in the mix, don’t be; that’s something the mastering engineer will handle. Keep in mind that increasing the bit depth does not lower the noise level. It will be administered in a proportionate manner (and that is a much higher noise than if the recording was first recorded on the higher bit depth).
Suggestions for lowering the noise level on the floor
Now that you know what it is and how it differs from dither, let’s look at some strategies for avoiding noise floor problems. Please keep in mind that these suggestions will not address all of your problems, but they may assist you in meeting low noise floor requirements.
- Choose high-quality microphones and preamps wherever possible.
- Isolate the microphone from undesired sounds as much as possible;
- Ascertain that your home recording studio is properly equipped with acoustic treatment.
It’s important to remember that it’s always better to deal with noise floor problems throughout the recording process. If that isn’t an option, use an equalizer to eliminate noise that is present in a particular frequency band. Parametric EQs, as previously stated, may assist you with this. However, don’t reduce it too much or you’ll end up with undesired audio effects.
Some sounds, on the other hand, are in a much more reasonable frequency range, and lowering those frequencies will undoubtedly alter the sound. In such circumstances, it’s OK to make a racket. If the volume isn’t too loud or if there aren’t any quiet or low-energy periods with less instruments, it’ll probably be buried in the mix.
Addressing noise floor problems at the source is a good place to start. It cannot be overstated how essential this is. It’s important to keep in mind that the mastering process amplifies all audio signals, including disturbances.
A noise level of approximately -60 dbFS is required by ACX (Amazon’s Audiobook Creation Exchange). Although I recognize that this may be difficult to accomplish, keep it in mind as a goal. If you get a reading of about -60, I’d say your studio is quite silent and up to recording requirements.
My last piece of advise is to work within your constraints. For whatever reason, don’t become overly fixated on establishing lofty objectives. It’s just preferable to establish more realistic and attainable goals and work toward them. If you use a meter to measure the ambient dB SPL level and get about 40-60 dB, that’s also regarded professional. But it doesn’t rule out the possibility of working with 20-30 people.