When you watch YouTube videos, can you can tell the difference between good sound and bad sound recording? Bad sound is distracting especially when the video is a speech.
When it comes to your own video recording of a lecture, seminar or workshop, always use an external microphone. With a proper clip-on microphone on the presenter, you will get crisp clear voice quality.
HOWEVER... sometimes things happen! Someone in the audience coughed loudly, an electrical buzz interrupted from nowhere or an intermittent static noise interfered with your wireless microphone.
The worst thing is... the unwanted sounds are recorded into your video even before you can react.
If you have a back up audio recording device, great!
Otherwise, the big question is "How do I remove unwanted background noise from an audio recording?"
First, let me classify some common noises into two types, random noise and constant noise.
- Random noises are like coughs, sneezes, phones ringing, doors slamming and chairs creaking. Mostly created by individuals in the audience that can occur at any time. If loud enough, even a good external microphone on the presenter cannot isolate the noise from his voice.
- Constant noises are like the hum from the air-conditioner blower, laptop cooler fan, nearby vending machine, electrical buzzing and ambient hissing. These sounds have fixed patterns. They may stop for a while, but when they are back, they will go on for a long time with the same tone.
Here I present to you 3 simple software solution to repair a damaged audio recording.
Audacity is a free open-source software for recording and editing sounds. It has features to enhance audio as well as to repair bad recordings. My favorite feature is "Noise Removal". It is great for removing constant noise in the background. All you have to do is to mark out a segment of that constant noise. Audacity will analyze the pattern of the noise and remove that pattern across the recording. Depending on the intensity of the noise, you may not remove it completely, but reduce it to a comfortable level.
- Adobe Soundbooth
Adobe Soundbooth is a tool for video editors to create and polish audio, customize music, add sound effects and more. It can automatically detect and fix common flaws in audio such as hisses, hums, crackling and pops. My favorite feature is "Autoheal". Like a doctor, it heals coughs... Soundbooth can remove random coughing noise. All you have to do is mark the tiny segment where the cough occurred. Soundbooth will remove the entire audio from that segment, then analyze the sound waves immediately before and after the deleted portion to recreate a replacement. I experimented and found that Autoheal worked well on a music recording but very bad on a speech recording.
- Sony Vegas
Sony Vegas is more than just a professional video editing software. It is also a superior audio production tool. This is the software I use most often to enhance seminar audio recording and remove random audio interference. There is no dedicated feature to remove audio noise, but tweaking specific audio filters can enhance speech quality. I use basic editing features like split, mix and level adjustments to fix sounds. Works most of the time as long as there is a backup microphone recording. Sony Vegas may not be perfect for audio repair but doing it within my video editing software saves loads of time.
These are great tools for repairing audio, but always remember... prevention is better than cure. Double check equipment before and after setting them up. Wear headphones and listen throughout the recording so you can react immediately to any disturbance. If budget allows, get a separate audio device to record a backup.
PS: Have you repaired an audio recording before? How did you do it? Please share your technique in the comment box below.