Saturday, September 26, 2009

How to Reduce Noise in an Audio Recording

In studio they are using expensive microphones and noise reduction foams for eliminate noise in audio recording but this could be not identical for home use and also it is expensive.

Here I have listed some tips which I found for noise reduction using almost any microphone in your own home, even with the internal Mic in your computer. Article divides into two parts, Mic Recording Noisenaturally reduce noises while recording and as well as eliminate noise in audio already recorded.


1. Recording Environment

Before worry about anything else get rid all possible noise in your recording space. Pick the least noisy area to record. Turn off any fans, heaters, air conditions, and other non-essential applications. Even an extra laptop or idle gaming console makes noise, so if you're not using them shut them off. Close the doors and shut the windows.

Place your microphone away from any remaining noise sources. Don't record next to a window, even if it's closed. Remember that your computer makes noise too! Even non-audible sounds will become noticeable once you amplify your recording. Finally, turn off any cell phones. Not vibrate, but off. You don't want to get any GSM buzz while you're recording.


2. Get as close to the Mic as possible.

The closer the microphone is to the audio source, the less background noise will show up in the recording. Positioning for tonality and comfortability has to be taken into consideration, but beyond that you simply want to get the mic as close as you can. Speak louder, or if you're recording an electric instrument turn up the volume. If your levels start clipping, bring the volume down on the mixer.


3. Tweak the EQ.

Once you've got your audio recorded, you can often eliminate noticeable buzz or hiss using the equalizer. If your mixer has equalizer presets, try playing with those before you start recording to see what bands you can turn down to diminish noise.

If you're mixing digitally, you can record the audio straight in without any EQ and apply one during the editing process. Finding the right equalizer band to mix down is often trial and error.

If it's a hissing sound, it's going to be in the higher spectrum. If it's a buzzing sound, it's probably coming from the mid to lower spectrum. A graphic equalizer is a great mechanism to form a valley in the EQ and move it around until the noise is reduced.


4. Use a Speech Enhancer plug-in.

All good recording application has inbuilt Speech Enhancer plug-ins. If you couldn't find one, try searching the internet for a third party plug-in. The Speech Enhancer will let you apply some quick tone settings to make a speaking voice sound more professional.

More importantly, it will give you the option to dial back the more quiet sounds in a recording. This will help isolate the vocal and push everything out. While this type of plug-in is meant for spoken audio, it can be used (with mixed results) on any kind of audio.

Note: speech enhancer can deteriorate the quality of your audio. While it's fantastic for several minutes of audio, using it across an hour long podcast where levels and noises are frequently changing could have undesirable results. The more noise you reduce, the more likely you are to find additional compression noise.


5. Know your noise gate.

The noise gate is your key to absolutely silent pauses and crystal clean audio. What the gate will do is take all noises under a certain level and turn them down however much you tell it to. If you find that your desirable audio never gets any quieter than -20dB, you can tell your noise gate to turn the recording down any time audio is not exceeding -25dB.

You can even tell it how much to turn it down - all the way for a clean recording, or maybe just a little to allow some natural hiss in. The noise gate appears easy enough on the outside, but can be a little complicated to master. If your settings are too high, you will clip out parts of your recording making it obnoxiously unlistenable.


If the above steps don't eliminate the noise in your recording probably you have some serious noise issues. For the really tough jobs you can use a noise reduction plug-in (like the one in Soundtrack Pro) to take a noise print and eliminate that print from the recording. You can also try a denoiser plug-in. These tools will get the job done, but not without sacrificing the quality of your recordings.

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