Home Non-Linear Editors: How To's How to Reduce Audio Noise in 4 Simple Steps: Video Edition

How to Reduce Audio Noise in 4 Simple Steps: Video Edition

how to reduce audio noise

It’s a well known fact that noise reduction introduces unwanted artifacts into your audio recording when used carelessly.

The processing of dynamic high frequency analysis introduces freckles, glitches and that underwater effect across the high frequency spectrum. Not good.

The good news is that using noise reduction plugins, or utilising noise reduction presets subtly and complimenting this process with EQ, we can bring noisy DSLR recordings back to life simply and easily.

Step 1.Use the ‘Learn’ Function

First off, all noise is different depending on the type of mic used in the recording, as well as it’s placement, the amount of gain applied and a number of other factors.

Noise Reducers can come with a ‘learn’ function. ‘Learn’ analyses the nature of the noise attached to your audio and creates a ‘noise profile’, which makes for more accurate noise reduction.

how to reduce audio noise
1Insert a Noise Reduction plugin on your audio channel or clip
2Look for the ‘Learn’ function of the plugin and click it.
3Press play to run your noisy audio through the plugin for some time. Analysis of the noise spectrum will begin whilst a ‘noise profile’ is being created.
4Slowly reduce the ‘threshold’ control whilst listening to the source audio

Step 2. Play with the Threshold Control

Noise reduction works best when you constantly play your audio source through the plugin and reduce the ‘threshold’ down very slowly.

noise reduction audio DSLR camera audio
1Whilst playing back your source audio slowly reduce the threshold control
2Listen not only for reduction of hiss and noise but also increases in unwanted artifacts such as digital bits and phasing
3Find a balance between satisfactory reduction of noise and unwanted artifacts such as fractals, crackle and smear
4Don’t worry too much about audio sounding dull and underwater, this can be corrected later
5Find a balance between a natural sound and a reduction in hiss and noise.

Step 3. Brighten and Recover

Now that you have reduced hiss and noise to a satisfactory level you’ll notice the source audio feeling dull and subdued, but only slightly.

The subtle use of DeNoisers is key here, to avoid unwanted artifacts from effacing the audio. Using EQ, Compression and Gain can recover from this underwater effect.

EQ is the tool you need at this stage.

1 Insert an EQ plugin directly after the Noise Reduction Plugin on your audio channel
2Look to engage the ‘High Shelf’ normally located on the far right of the EQ
3This will lift frequencies in the high range bringing clarity, brilliance and air back into the audio recording
4Select a frequency between 10,000Hz (10kHz) and 12,000Hz (12kHz)
5Set the gain from between +3db and +6db
6Set the output gain on your EQ plugin to +1.5dB

Step 4. Zone In On the Sweet Spot

With all audio, no matter the source, there will be a sweet zone of frequencies in the high range that when subtly boosted will add sharpness and intelligibility.

The human voice piques our interest at around the 1,000Hz (1kHz) range.

Our ears have natural abilities at these frequencies, which is why we can often pick out distant human voices despite being smothered in external environmental sounds.

1Set a frequency band control to 1000Hz (1khz)
2Set it’s gain control to +6db
3Slowly sweep the control from 1kHz to 9kHz listening carefully to your camera audio recording
4Find a spot where things pop out a little more but don’t re-introduce the noise you were experiencing.
5Now reduce the gain of that EQ control from +6dB down to +3dB to settle on a subtle boost of the sweet spot

Perfection is Inhuman

It’s worth considering that recording perfectly crisp, clean, super-quiet audio is not possible for the majority of us, and nor is perfect audio always desirable.

Some noise can add analogue character to a recording and noise reduction plugins can only go so far as to tame problem source audio. That said, noise issues are a common problem and the key is to use DeNoisers subtly, then compliment this transparent processing with EQ.

I hope this article is inspiring and helps you tame unwanted hiss and noise in your DSLR recordings.. let us know how you get on!