Sound Effects

‘Sound Effects’ (aka ‘SFX’, though this acronym may get confused with the acronym for Special Effects as well) are sounds that are used in various forms of media, other than the sounds of human speech or music.

Sound effects (typically digital in nature, living as a file on a computer) are recorded and edited, or synthesized artificially for use in some medium. This medium could be a theatrical play, film, television broadcast, radio broadcast, podcast, video game, application, or any other medium that can facilitate the playback of a digital sound file. Sound effects can also be of analog or acoustical nature and originally arose in use in early theatrical plays, providing an additional story-telling element (ex. a large metal sheet replicating the sound of thunder during a loud storm).

Recording Sound Effects

Nowadays, sound effects are typically recorded on portable field recorders using different types of microphones and microphone arrays to capture different spatial qualities and frequencies balances.

Various special microphones, like hydrophones and contact microphones, allow sound recordists to capture frequencies present in places humans may not ordinarily be able to listen, and may not be able to record with traditional microphones. Every microphone has a different capability in terms of frequency response, maximum Sound Pressure Level (loudness) and internal noise. Knowing how and when to use the different microphones available is important to the capturing of sound effects.

Every sound effect will sound different depending on how it’s recorded, making the need for an expansive collection of SFX prevalent when working on a large project like a film, television show, or video game.

Some sound engineers specialize in recording sound effects and focus solely on this aspect of sound. For instance, Soundsnap is a sound effects library that contains thousands of sound effects from various contributing recordists.

Sound Effects in Film

In the world of film and television, sound effects can be sometimes used synonymously with Foley sound, however, there is a clear distinction between the two. Foley is the creation of sound effects in real time, performed and recorded to the picture. Sound Effects are pre-recorded and potentially pre-designed files that get edited into a film or tv show in post-production.

Audio engineers involved with sound effects on a film are often given one of the following titles (though variations of these may occur):

  • Sound Effects Recordist
  • Sound Editor
  • Supervising Sound Editor
  • Sound Designer

Sound Effects in Video Games

In video games, sound effects are often cut, designed and optimized to serve as many functions as possible, to optimize efficiency on the CPU, RAM and game file size. For instance, in the code of the audio engine for a given game, events are built from multiple smaller sound effects via layering and applying real-time processing to them to alter them in some way. By keeping the SFX in smaller individual pieces, a video game sound designer can reuse and rearrange them to create a more dynamic sonic palette for the world of the game.

Common File Types for SFX

Since Sound Effects are carried in common audio files, they most common professional formats for this are either WAV (or BWAV) or AIFF, both of which are raw and uncompressed. When using compressed sounds, MP3 is the most frequent codec used. When using MP3 sounds, a high bit-rate is preferred (ideally 320kbps). In video games, another type of container is often used called an OGG file, in which the designers can get smaller file sizes in an uncompressed format as to reduce the load on the CPU during the game’s runtime.

Professional bit depths used are an absolute minimum of 16bit, but nowadays should really be at least 24bit to get the most flexibility and dynamic control of out the sound.

Sample rates should be an absolute minimum of 44.1kHz, but 48kHz is the standard sample rate for ensuring proper sync to film, thus most films are mixed in 48kHz and so your sound effects should follow suit when possible. A newer standard for professional sample rates is a minimum of 96kHz as large blockbuster films are now being mixed in that sample rate. However, even if the film is not mixed in that sample rate, having access to a higher sample rate like 96kHz or 192kHz gives sound designers more flexibility to time and pitch adjust the sample, therefore creating entirely new sounds.

Sound Effect Libraries and Royalty Free SFX

Libraries or collections of SFX are often recorded, edited and put together for one of two purposes;

  • Internal use for a production facility/studio and its team for use in current and future projects
  • For commercial resale, so that other sound designers, editors, or any other kinds of content creators may have access to the sounds.

In the case that they’re for commercial use, the sound effects are considered Royalty Free, and may typically be used any number of times after the initial purchase without needing to pay a recurring royalty at any point afterwards, so long as they are not individually resold as is (that is, they must be used in a larger project, or modified in some reasonably significant way).

The term ‘royalty free’ is not to be confused with ‘free’, as the 2 terms are unrelated.

Soundsnap’s entire library of 250,000+ sound effects is entirely royalty free and may be used as many times after purchase as desired.

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