What does Background Noise Entail?
Regardless of whether you are in a home studio or an acoustically treated room, you are bound to get some background noise when setting up a recording. Recording technicality requires you to assess the space that you are recording in. There will always be instances where unwanted sounds creep in, some of which would qualify as intermittent noise (sound that does not occur continuously, such as a train passing by).
Recommended Read: How to Use Noise Gate in Adobe Audition
It is important that you maintain the quality of the recording from start to finish. It might be a case where you pose a question to your co-host or guest and at the time they are giving their answer a train passes by. You may mute your mic at that instant but some of the sound is going to go on tape. While the noise here would be pretty obvious, oftentimes unwanted sounds (ones you are not consciously aware of) make their way into your recordings. As a musician or a studio engineer, it is important that you address those so your recordings are noise free.
Lastly, before we get to removing the noise using Adobe Audition let us go over the low-frequency noise type. Unlike intermittent, LF noise needs a keen ear to establish its presence. The noise may emanate from an air conditioner fan that is placed in a corner of your recording studio. You might have thought that getting a quiet fan was the way to go but chances are that the mics that you use are super sensitive to low-frequency sounds.
How to Check If your Recording has Background Noise
Before I start any of my recordings I look out for both of the noise types mentioned. Here are two scenarios that I encountered.
In the first, the recording was an interview in an office where the recording crew carried the equipment. A couple of floors below the office there was construction work going on with much noise coming from drilling equipment. This was coupled with traffic noise as this establishment was in an urban settlement. For such types of noises, nothing much can be done. Effects can be added to the audio file but it will mess up how the voices sound as well. Bits of the noise can be reduced nonetheless.
The second scenario which will be the reference point in this article is a recording that was done in a studio setup. How we speak varies from one person to the other, the host of the show had a guest who was soft-spoken with a gentle voice. In such a case you adjust the gain knob on your mixer for that particular mic.This is done to increase the level of audio that you are getting on your laptop. The downside to adding the gain is that you get increased white noise. White noise is the low frequency with a “shh” sound.
Here are two audio files zoomed in. In this first image, there is a bit of white noise. Look at the section where there is no audio waveform for a few seconds. You will notice a not-so-smooth line.
Here is an audio recording in an acoustically treated room with the gain set at an ideal level hence picking no room noise.
Remember that this is not the sole way to identify low-frequency. At times you have to listen back in addition to looking at your audio waveform.
How Do You Remove Background Noise in Adobe Audition?
Open your file in Adobe Audition. Here is what my file with noise looks like.
To remove noise in Adobe Audition you need to select a portion of your file. Analyze the selected part for the software to know what treatment is needed. Lastly, select the whole file or the section where the problem exists so that the treatment is applied to the other part. Here is the step-to-step process.
First, select a part of the audio. Note that find a long part where the noise exists so as to select as much noise as possible.
This is the part that will be analyzed. To analyze this part click on Effects on the menu tab and scroll down the option to Noise Reduction/ Restoration option. Hover your mouse pointer on this option. A new drop-down option will be opened. Under these options click on Noise Reduction (process). Alternatively, you can use keyboard shortcuts: Ctrl + Shift + P.
Once done this dialogue will pop up. Click on Capture Noise Print.
The dialogue box will now look like this.
At this point, you selected a part of your audio that had the noise and now by clicking Capture Noise Print Adobe Audition has assessed the frequency and given you an ideal level to apply to the rest of the file to reduce the noise across the whole audio file. Next click on Select entire File as shown in the image above.
If you look at the lower part of the dialogue box you will notice two lines with levels added to them.
One is Noise Reduction and it is labeled as a percentage. Once you have selected your whole audio file you can use this to adjust by dragging the circle from left to right. As you do this make sure the audio is playing in the background to assess if the changes being made sound okay or whether they are messing up the audio quality. The more you drag it towards 100 the more you reduce the noise level.
Scrolling the second one allows you to change the level of the noise decibels. Decibels are simply the units to measure sound. So dragging the mouse along this line level towards 100 allows you to reduce the noise level. Mostly you will not need to adjust this level.
Another important feature of this dialogue box is the power button. This will appear on dialogue boxes that you use to add effects to your audio files. If it is on green it means it is on and the audio that you are editing has the effects and if it is off the audio does not have the effects hence you are still listening to the raw unedited file. This helps in listening to the audio file without the noise reduction effect and comparing it with one with effects added.
You can drag this dialogue box a bit to the side by clicking and dragging it by the top white part. Now that you can view the file in the background better click on random parts of the file to assess how this effect has been applied to these different parts. To do this click on the highlighted part below.
It is important to do this so that the effect has a negative touch on some parts of your file. If you are content with how it sounds click Apply in the dialogue box. Your file has now either eliminated the noise or lowered it.
Click Ctrl + S to save your file.
Alternate Way To Remove Noise – Using DeNoise.
There is an option that you could use to remove background noise. Click on effects on the menu tab. Scroll down to the Noise Reduction /Restoration option and hover your mouse pointer on this option. A new dropdown with new options will appear. Under this click on DeNoise.
After clicking on DeNoise a new dialogue box will pop up.
Under the presets dropdown list options there are three options. A custom, default, light noise reduction, and heavy noise reduction. Don’t change this. The only time I get to apply a different preset myself is when the audio’s background noise was a bit louder.
On the lower side of the dialogue box there exists a slider to reduce the noise as you gradually drag it towards the 100% mark. Drag it as the audio till you get the noise removes as much as possible and the audio sounds ok.
On the right side, there are bar-level meters. As you are editing Click on the box next to the Output Noise Only to select it. What this does is it allows you to listen to what noise is being removed. You might notice a few of the speakers’ words are affected but this is okay. Unselect it.
Once you are done dragging the slider to an ideal position which makes the audio sound better click apply to effect these changes.
Finally, save your file.
Conclusion
As an audio editor, I have at times been sent audio files and my feedback was that the file in question has no perfect remedy to it. Let us say you are recording and someone walks in and throws a bunch of keys on the table. The recording software will pick both sounds, yours and the jingle of the keys. In such a case removing that noise completely is a pipe dream. So strive to reduce and not remove it.
As you are dragging the reduction levels always have your audio playing back. Do not eliminate the noise completely and in turn, mess up the quality of how your audio sounds.
