How to Clean Up Your Audio Recordings

No amount of digital processing and mouse clicking is ever going to fix a poorly recorded track. However, you can make many improvements to flawed recordings; in fact, there is a plethora of specialized software programs designed for these specific functions.

There is no reason to go out and spend loads of money on a batch of new software when the ability to clean up your recordings is available for free with a few minutes of Web searching, some research and perhaps a little experimentation. The freely downloadable Audacity audio software is a good place to start.

Here, we will begin with more jarring audio anomalies, often referred to collectively as "clicks and pops.' These can occur as a result of noise on a scratchy old LP you used as a source for a recording, or they can be digital glitches in a badly encoded audio file. Either way, the track will never sound pristine unless you can re-record it, but you may be able to make a subtle improvement if the original source is not available.

Open the track in Audacity with File > Open, then make sure you can see the entire waveform as clearly as possible by choosing View > Fit in Window and then View > Fit Vertically. This way, you'll be able to see the changes you make as clearly as possible.

Select the entire waveform by choosing Edit > Select > All, then choose Effect > Click Removal. The dialog box that appears will give you adjustable options, but the best option to start is to use the defaults. Press the Remove Clicks button.

Listen to the resulting track, then select Edit > Undo and listen to the original as a comparison. The clicks may be less apparent, but does the presence or volume of the music suffer as a result? You can Redo and Undo as many times as you like, or use the Preview setting on the Click and Pop Removal dialog box while adjusting the settings. At higher settings, the Threshold slider will remove less sound. The Max Spike Width slider refers to spikes in the waveform, because clicks tend to be very narrow spikes and a higher setting will thus remove a wider range of noises, but may interfere with actual musical sounds as well.

You can perform this procedure on just a small portion of the track as well by manually selecting it with the Selection tool. This can be very handy when cleaning up the beginning of the first track from an old vinyl record, where there may be more crackle than on the rest of the album.

Sometimes there will be just one irritating little pop on an otherwise pristine track that you simply can't ignore. A sound like that can usually be removed with a quick edit.

Listen to the track in Audacity, and stop playback just as you hear the offending noise. Zoom in a little, put the cursor back to just before the noise on the waveform, and listen again, stopping again just as you hear the noise. Repeat this procedure a few times until you can actually see where the noise is represented on the waveform, then place the cursor there and zoom right in to sample level, in other words, you should be able to see little dots along the waveform representing each individual digital sample.

Check both the left and right channels. If the anomaly is tiny enough, you should be able to smooth out the path using the Draw tool from the upper left corner to select and drag that part of the waveform more or less into line with the surrounding pattern. This takes some practice, so don't hesitate to use Undo frequently as you are learning.