Using Broadband Noise Reduction

For more information, see the following topics:

Performing Noise Reduction on Audio that Lacks a Noise-Only Portion

Editing the Contour Line

Before you start using BNR, take a moment to think about the nature of the noise in your session and where it’s located: Is it on a single track, or several tracks? Is it a single type of noise, or several different types? The answers to these questions will affect how you use BNR.

If there is a single type of broadband noise on a single track, insert the BNR plug-in onto the track. Solo the track to make it easier hear as you remove the noise. If a single track contains different types of noise, you may need to use more than one DINR insert to remove the other types of noise. If multiple tracks contain the same noise, you may want to bus them all to an Auxiliary Input so you can use a single DINR plug-in insert. This will minimize the amount of DSP you use.

To use Broadband Noise Reduction:

1 From the Insert pop-up on the track with the noise, select BNR. The Broadband Noise Reduction window appears.

2 In the Edit window, select the noisiest portion of the track—ideally, a segment with as little of the desired signal as possible. This will make it easier for BNR to accurately model the noise. If the track contains a segment comprised of noise only, select that portion.

3 Do one of the following:

Start audio playback, and in the Broadband Noise Reduction window, click Learn. BNR samples the first 16 milliseconds of the selected audio and creates its noise signature.

– or – 

Locate and identify noise on the fly, during playback, using BNR’s Learn Last Audio mode. To do this, Alt-click (Windows) or Option-click (Mac) Learn. Begin playback, and when you hear the segment that you want DINR to sample as noise, click Learn a second time. BNR will build a noise signature based on the 16 milliseconds of audio immediately preceding the second click.

4 Click Fit. BNR will fit a Contour Line to the noise signature just created. If you want to create a Contour Line that follows the noise signature even more precisely, click Super Fit. A Contour Line with five hundred breakpoints is created.

5 To audition the effects of the noise reduction interactively, in the Edit window, select a portion of audio containing the noise. Then select Options > Loop Playback and press the Spacebar to begin looped audio playback.

6 Adjust the NR amount slider to reduce the noise by the desired amount. To compare the audio with and without noise reduction, click Bypass.

7 To fine-tune the effects of the noise reduction, adjust the Response, Release, and Smoothing sliders to achieve optimal results.

8 To further increase noise reduction, edit the Contour Line. The quickest way to do this is to move the entire Contour Line upwards. In the Spectral Graph, Control-drag (Windows) or Command-drag (Mac) to select the entire waveform range. Then click the Move Breakpoint Up button. The higher you move the Contour Line above the noise signature, the more noise is removed. See Editing the Contour Line.

9 If you feel that some of high end frequencies of the audio have been lost due to the noise reduction process, try using the High-Shelf EQ to compensate. To do this, click BNR’s Hi Shelf button and adjust the frequency and gain sliders until you are satisfied with the results.

If you are happy with the results of the noise reduction, use the Plug-In Settings menu to save the settings so that you can use them again in similar sessions.

To enable Learn Last Audio mode, Alt-click (Windows) or Option-click (Mac) the Learn button. This button flashes red when armed for Learn Last Audio mode. When you hear the target noise, click Learn a second time.