My friend and I are finishing up our first game right now and I have just discovered that even though he can make some decent music tracks, he has no idea how to make a sound effect. An explosion, for example.
How are sound effects made?
My friend and I are finishing up our first game right now and I have just discovered that even though he can make some decent music tracks, he has no idea how to make a sound effect. An explosion, for example.
How are sound effects made?
Do some research on what a Foley Artist does:
They can be everything. This is one of my favorite things to experiment with. I don't worry about "This could be a --- sound" I only worry that "this sounds interesting" at all times. For example Overgrowth has blood squirts from only slightly modified recordings of them squeezing a pineapple's insides by hand.
My bone cracking sound in my game is from celery and onions being broken and cut. Vegetables and strange gooey substances work great. I've used a VERY modified version of my local TRAX station recording (sounds of a train taking off) close to the ground as a gun boom. It works great too. Experiment it's fun. If you want explosions it would be things like that, things that have lots of changing over time, that isn't very abrupt or necessarily loud. Anything can be altered. Use the train as an explosion. You could just as easily use some old tile from your neighbors alley, or a cardboard box with rocks in it and drop them on concrete.
And yes, this is how it's done professionally too. An example is that a lot of the sounds of Zerg units in Starcraft II are from the sound designers squeezing hand soap in a bucket.
Foley sounds.
There is a video here which is a live recording of some guys from Dark Sector making sound effects for the game. In the clip they use:
Note the tarp floor, which gives a special "scattery" sound when the seeds hit the floor on the first watermelon hit.
An alternative youtube link here
I think the real answer is that most aren't, people just buy and use banks of existing effects.
You might find free sound effects online www.freesound.org has lots of sound effects, but they're under the Creative Commons Sampling Plus 1.0 license meaning you have to attribute the author for each and every one you use.
Alternatively, you could record sounds yourself and mix/edit them in a free program like Audacity.
The websites and programs answered so far are definitely the way to go. Recording your own explosions is no good. Most likely, any level of explosion you create will not sound much like what you're looking for anyway.
Not to mention, programming with a few less fingers would be tough.
Edit: However, as I'm thinking about this, one practical effect that could be pretty well recorded is that of gunshots. There's most likely a shooting range that rents out pistols and, as long as you call beforehand and make sure the range owner is alright with it, you could probably bring in a microphone for, at the very least, a trial run of how the recordings could sound. It's worth noting that, depending on the range, an indoor setup could likely make for some undesired echo if their sound dampening isn't well done. And, of course, have one of the employees supervise if you're not experienced with firearms.
You could try some dynamic sound effects generation where sound parameters would depend on your game action. For example, try Little Endian sound mangling SDKs.
Have fun making your own sounds.
If you are making a retro game I recommend trying out cfxr. It is a random sound generator and the sound effects sound like they would work well in a retro arcade game.
It is possible to create your own sounds with Software, a free software is for example Pure Data, but also any Software Synthesizer with enought variability will do it.
Here are some sources for sources of sounds i found and use
Free
Non free
Search machines
soundbible.com has a lot of free sounds with different licenses for whatever you are using them for.
bfxr.net is a new version of the popular sfxr program. This version has some new features for better sounds like new waveforms and filters.
The people who do these sound effects are called Foley Artists. They do things like throwing pots and pans and squishing fruit for different sound effects in video games and movies. http://en.wikipedia.org/wiki/Foley_(filmmaking)
If you want to you can try and make your own sound effects like squishing hand soap or boiling water to make lava bubbling sounds. Then you can digitally change the sounds for even more effects! Their are many different options to make cool sounds!
Actually this is a self discipline, called "sound engineering".
There's a guys in a movie industry for example, even whole compamies, which work is to create sound effects for movies, series, video games.
If you're writing a simple game, you can pick some open source sound library, which contains sfx'es for blows, explosions, whatever you need, or to buy a licensed one and use it.