Whether you're new to sound design or it's of old hat to you it's always a great time to review the different sound effects categories. If you know what type of sound effects you are looking for it will always be easier to narrow down the sound effects.
To start off with there are basically five different sound effects categories. Webster's dictionary defines sound effects essentially as imitative sounds that give productions the illusion of reality. In today's culture with media being so main stream, sound effects are critical to making music, film, radio, and podcasts all stand out.
When going over the different categories of sound effects in the film industry, they are usually divided into five main different types of categories. Here they are:
Hard Sound Effects – Hard sound effects are definitely the most popular sound effects used in film making and usually come in a larger sound effects library. They usually evoke a clear "hard" sound and would be something like a gunshot, or a door slamming, glass breaking, or a car crashing. They are fairly easy to put into a production because they don't have to be synchronized exactly to the action. They quite easily evoke realism in the production when they are there because the sound effects are easy to associate with the action.
Foley Sound Effects – Foley sound effects are usually what add a lot of realism to a production. The most common known Foley sound effects are footsteps. Because one would typically hear sound effects such as footsteps in real life, something "small" as having footsteps in the background to a person approaching making a big difference in the production of a movie. You can easily get Foley sound effects available in a Foley sound effects library.
Background Effects – Background effects are often also called ambience effects. They typically do not correlate to anything specific happening on the screen; but instead, give the listener the feeling that they are in a specific area (for example New York). If you see a scene in downtown New York, typically you would expect there would be sound effects such as honking horns etc. Those are background sound effects (ambience effects).
Electronic Effects – Electronic sound effects are typically more like synthesizer and electronically produced sound effects. They will often be used in something like a title scene or special effect.
Design Effects – Design sound effects are exactly what it sound like. Design sound effects are specially designed in situations where it's basically impossible to create that sound effect naturally. Example would be if it's a really small noise such as a pin hitting a tile floor it would likely be easier to create that sound that try to record it.
Well, that's an overview of sound effects in the production world. Whether you create them yourself or buy them in a sound effects library you'll typically have your sound effects fall into one of these categories.