It's essential to constantly monitor the signal and listen for problems such as levels set too high and stray noise. As with video, post-processing can greatly improve results even when audio seems perfect. There are four basic filtering procedures that almost always help. As with all of these recommendations, test profusely before applying them in crucial situations and be sure to use a copy of the original file. Once the audio is recorded, it may seem too late to apply compression filtering.
Normalization brings the highs and lows of the audio signal closer together.
Noise gate filters act like automatic volume controls. When relative silence is detected, audio gets muted, potentially eliminating background noise, which is particularly handy for public speaking situations. Crowd noise or air-conditioning rumble can be eliminated during pauses. Another glitch good to minimize is DC Offset. This error is quite common, thus many audio and video software tools include a DC Offset filter, which often can be applied on the fly.