The Noise Reduction feature can considerably reduce the background sounds such as a whistle, hum, whine, hiss, buzz and the list is endless.
Noise Reduction can decrease constant background sounds such as hum, whistle, whine, buzz, and “hiss”, such as tape hiss, fan noise or FM/webcast carrier noise. It is not apt for individual clicks and pops, or asymmetrical background noise such as from traffic or an audience.
To use Noise Reduction feature in the software, you need a region in the waveform that comprises lone the noise you want to decrease.
Be mindful that it may be intolerable to get a satisfactory elimination when the sound is very loud, when the noise is changeable, when the music or speech is not much flashier than the noise or when the noise incidences are very like to those of the music or speech.
If your problem is mains hum or a high-inclined signal, the use of a Notch Filter may help, which must be approved out before smearing Noise Reduction.
Get Noise Profile
This first step demonstrates Audacity about the noise you want to eliminate by classifying the noise floor of the different occurrences that make up the noise.
Reduce the Noise
Pick the entire region of the waveform from which you want to decrease the noise, and then set the Noise Reduction limitations. This is frequently done by trial and error method, regulating the sliders and using the Preview button to listen to a few seconds of audio after noise lessening. Snooping to the Residue (the sound that will be clean out when you apply “Reduce”) can also be valuable in defining how much harm is being done to the wanted (non-noise) sound.
It controls the amount of volume decrease to be practical to the recognized noise. Use the lowermost value that decreases the noise to a satisfactory level. Higher values than essential may make the noise even lower but will result in damage to the audio that rests.
It also controls how much of the audio will be measured as noise, on a scale of 0 (off) to 24 (maximum). Greater sensitivity means that more noise will be impassive, perhaps at the expenditure of eliminating some of the anticipated sign as well. Lower values may affect the arrival of relics in the noise-condensed audio. Set this control to the lowest value that attains real noise removal without the outline of objects.
The frequency soothing option controls at values or higher the noise reduction into a stated number of neighboring bands. This adapts the sign you were expecting to keep, but if relics continue in the noise-abridged audio the flattening can make those relics sound more satisfactory. There is a chance that leveling will make the anticipated audio less clear, so where your anticipated signal is sturdy and of the wide frequency range and the noise is bright, try leaving this control at 0 (off).