Tuesday, June 28, 2011

Noise Reduction Software

by: George Smith


Remove hiss, hum, sounds of wind and rain, audience noise, pops, clicks, crackle, and all background noise from recorded audio with the Noise Reduction Effect.

The Noise Reduction Effect is sold as a plug-in to Blaze Audio's RipEditBurn Plus, RipEditBurn, and Wave Creator.

1. Locate a section in your audio file which contains just noise (hiss, hum, crackle, audience noise, pops, clicks, rain, and other sounds that persist during the recording) but does not contain music or voice: a section which otherwise should have been silent. Noise can often be isolated at the beginning or end of a file, and in pauses in the sound during the music. This section can be very short. Selecting the area around a short silence in the music and enlarging the waveform (View menu->Zoom to Selection) can make it easier to find areas that only contain noise.

The Noise Reduction Effect includes 8 preset samples of common audio noise, in case you cannot find a silent section in your file.

2. Select the Noise Only section in your file by holding down the left mouse button and dragging the cursor over the area with the noise you want to remove. The selection can be quite short. The selected area will be highlighted.

3. From the Effects menu, choose Noise Reduction. The Noise Reduction Effect dialog box opens. Save your noise profile for future use by checking "Save Profile" and entering a name in the window. Click on the Calculate Noise Profile button. This will build and save a noise identity for the selected section. The dialog box will close automatically.

Select the section of audio which needs to be cleaned, or select nothing if the entire file needs to be cleaned.

Once again, choose Noise Reduction from the Effects menu.

In the dialog box, use the Noise Reduction Level slider to set the level to 3.

Click on the Remove Noise button. The noise will be subtracted from the file, using the last calculated noise profile, unless you select a different noise profile from the drop-down menu. Listen to the results.

The noise in the file on the left has been removed. There is now silence before the music starts, as represented by the straight line, and the noise of the audience has also been removed from the music itself.

If the audio is distorted, click Edit->Undo, select the section of audio to be cleaned (or select nothing if the entire file needs to be cleaned), select Noise Reduction from the Effects menu again, and this time, reduce the Noise Reduction level one step, and try again.

There's no need to calculate Noise Profile again for the same file (in fact, if you saved your profile, it will now appear in the drop-down menu next to Load Noise Profile every time you use the Noise Reduction Effect).

If not enough noise is removed, undo the operation and, open the Noise Reduction Effect again, and set the level to a higher number.

Noise Reduction Level: This controls the intensity with which the noise components are removed. A high value will remove the noise more aggressively, but might also affect the original voice or music. A low value will remove the noise less aggressively, affecting the original voice or music less, but at the cost of leaving some noise in the signal.

The Noise Reduction Effect is sold as a plug-in to Blaze Audio's RipEditBurn Plus, RipEditBurn, and Wave Creator.

Visit www.blazeaudio.com to learn more about these programs.