I recently was contacted by a student in sound design asking for advice on the subject. While I was slightly intimidated by the request, since it is very much amateur hour here at Somewhat Soft, I wrote simple advice and let them in to the process of sound design as I do it for the games we've put out so far. Don't expect any masterclass material, but I figured some information could be useful to anybody starting into the medium.
On the importance of sound
First of all, sound is really important. Like, REALLY important. No matter the visual art style of a game, if you make excellent sound design, the entire game world will be instantly more believable and immersive to the player. I'd risk going as far as saying sound is the actual most important element of immersion, at least to me as a player. So...no pressure.
The way I work usually involves perusing sounds on the internet first and foremost. I use resources such as Zapsplat or even Youtube to find the sounds that best fit my needs, while always making sure they are copyright-free or under creative commons license (to the best of my knowledge, at least). Of course, the sound needs to be clean and without white noise, because you cannot mix-master your way out of a bad original recording. In that way, Youtube is less useful for sound effects, but perfect for different white noises / long ambiance samples. In the event I cannot find what I need, I make it myself. This is a more time-consuming process, which is why I only do it if I really need to, because as an indie dev, I wear too many hats to spend too much time on one thing. I have an old Zoom H2 recorder, and some sound-absorbing foam panels, so I create a little closed-off sound-proof space in my home office to record the sounds or voices needed.
Personalized sounds
As a general rule of thumb, I always try to add at least one very original sound to the design of a scene, to make it memorable to the player, even if they won't consciously notice it. For example, I've spent an awful lot of time designing the sounds for the fridge in the kitchen of our SPEK.TAKL game, so that whether you open the fridge door or freezer door, you can hear two different motor noises, since in real life, they do not make the same sound, obviously. You can technically play the entire game without opening either doors to the fridge, and the vast majority of players will not pick up on the subtlety, but I've seen at least one let's player comment on it, and this justifies my effort. It's just the kind of small detail that will add a realness to the experience.
I never use a sound as-is. I always need to 'make it mine' by at least mastering it, or modifying it in one way or another, layering it with another sound (even if the volume level of this second sound is kept to a very low minimum, so as to only add a little texture).
A quick note on music
When it comes to music, while I am an untalented musician (I cannot read sheet music, for example), I play it literally by ear. I compose electronic music, but I always aim to keep a human or imperfect element to it. Electronic music can sound so tight and structured, so you need to muddle it up a little, either by using quantization, using a mod wheel to modulate the sound, or throwing in samples of actual instruments here or there. Never make a song where the imprint of a human hand cannot be heard or felt, that's my motto.
The gear
Here is a non-exhaustive list of the equipment I'm using at home : Software : -Ableton Live 9 Suite
-Audacity -Sony SoundForge Equipment : -Zoom Audio H2 Recorder -Akai Synthstation 25 Midi Keyboard
-Audio-Technica AT2020 Microphone
-SoundBlaster Audigy Sound Card in my PC
-Behringer Xenyx Q1202 Mixer