Avoiding Unwanted Background Noise When Recording Sound Effects
By Alan M McKinney
When recording sound effects, usually a clean isolated sound is required with no unwanted background noise. Even noisy ambiences can suffer from undesirable noise and once it's been recorded, it's usually very difficult, if not impossible to remove. With increasing traffic on our roads and more and more aircraft in our skies, recording outdoor sound effects can be tricky. But even the natural sounds around us can be undesirable too. Insects, birds, wind, the ocean... We can't control them so how can we eliminate them?
Planning is the key and if possible, visiting the recording location a day or so before you plan to record can save you coming back with unusable recordings full of background noise. Sit quietly and listen to the environment at the location and make some test recordings to take back with you. Listen to these for any undesired sounds such as people, trains passing by in the distance, aircraft noise, distant traffic, birds, insects and anything else.
Try Different Times
Many of these sounds can simply be avoided by making the recording at another time of day, especially at night. There will be fewer people, aircraft, trains, less traffic, birds and many insects quieten down at night time too. Rush hour is going to produce louder traffic noise, birds make more noise at dawn and dusk and at weekends more private aircraft are likely to be in the skies. By avoiding these times, you can cut the amount of background noise down massively and come away with much cleaner recordings.
Recently I found the perfect stream to record for a project I was working on. The problem was traffic noise from the busy road nearby and birds during the day. Also the stream was situated in a public garden so people were an undesirable noise and it was closed and locked at night. However the stream produced exactly the noise I needed so I was desperate to get in and record it. After a quick call to the owners I was able to get access to it at midnight the following night and the difference was amazing. Absolutely no noise was present apart from the stream and I got the perfect recording.
If the ocean is an undesired sound at the location you're recording in, check tide times. The ocean is at its noisiest when the tide is low and can be extremely loud and audible for quite some distance. Therefore try recording at this location when the tide is at its highest for the best results.
Wind can only be heard when it's blowing against something so if you're trying to record a sound at a location with lots of trees, heavy plantation, wires/cables etc. you may find even a light wind creates unwanted background noise. You may find yourself waiting for a day of no wind before that location becomes viable. Wind can also carry background sounds over long distances. The sound of traffic for example can be carried several miles downwind so it may be necessary to record on a day the wind is blowing in the other direction or if possible, record upwind from the traffic. Traffic will also be louder if the roads are wet so if it has been raining, wait for the roads to dry out before attempting to record. After a heavy rainstorm, water will be dripping from roofs and trees and running down guttering and drains etc. So if you've been sitting out a rainstorm waiting to resume or start recording, give the water a chance to stop running and dripping otherwise it could well become yet another unwanted background noise.
There are many more sound sources of undesirable background noise that you'll encounter when recording sound effects outside. However, with a little planning and a lot of patience, you'll become a master at utilising all that a location has to offer and come away with clean, professional sound effects.
Alan McKinney is the founder and co-owner of http://www.soundscalpel.com and professional sound designer with over 15 years experience