Using Sound In Horror Games
by Robb Neumann

Few genres in gaming rely as heavily on the building of tension as the horror genre. The suggestion of danger in a horror game can often been more satisfying and ultimately more successful, than the actual threat. For this reason, horror seems to stand out as the ideal genre for using sound effects to add tension to a game.
Although horror seems like the perfect genre for the use of sound effects, the tips provided here can be used for any game or setting. The sounds of a plane approaching, for example, could have a huge impact in a wartime campaign. Or, the sound of gunfire could alert the PCs about nearby people in a post-apocalyptic game.

1. Be Prepared
This is obvious. If the goal is to add sound effects in the least intrusive way possible, the Game Master needs to be an expert in how to use her MP3 player in the most efficient manner possible. Make sure that the MP3 player doesn't have a shuffle option turned on, that everything is setup properly (the speakers are turned on, plugged in, etc.), and that the GM can get to the player with the least amount of fuss during the game. Practice using this setup before the game starts will allow for time to properly troubleshoot any potential technological difficulties.
If at all possible, make sure the speakers are either located away from the gaming environment or out of sight of the players. Computer speakers are great for this, because they're often small enough that they can be placed almost anywhere. Set them on the floor, several feet away from the gaming table. Or, place them behind the sofa if you're going to game in the living room. The options are limited only by your particular gaming environment, of course, but the goal is to keep the speakers from getting any attention at all. You're the main entertainment, not the speakers, so keep them from attracting any interest from the players.
Test their volume before you start playing, if at all possible. Something that comes across too soft is better than something that comes across too loud, but you want to make sure the speakers can be heard from where the players will be sitting.
If you're hosting the play session at your house, you will have the luxury of being able to get set up far in advance. Use that time!
2. Never Replay A Noise
If things are going well, you may have a player gasp, "What was that? Play it again!" Don't do it. If there is anything that Hollywood has taught us, through countless horror movies, its that not knowing is far worse than having something shown to us. So, if a player wants to hear a noise again, refuse. Let them try to reimagine the noise in their minds. Chances are it'll be much better, and significantly more creepy, than anything you have on your hard drive.
3. Don't Overdo It
Use noises sparingly. The more sound effects you add, the less important they become in the long run.
4. Use the Noises Appropriately
Never penalize someone for not hearing a particular noise. Remember, the sound effects are meant to enhance the atmosphere of the game, not replace the normal skills and judgment of a Game Master. So, don't set up situations where properly hearing a noise could have an effect on the outcome of the game.
For example, you don't want the PCs to stumble across a door, play a growling animal noise, and then announce that they are automatically dead once they open the door because they should have known that the "hound of hideous death" was behind the door.
Also keep in mind that not everyone has perfect hearing. As a Game Master, you have a number of responsibilities to juggle, but if you add sound to your game, sensitivity towards differing hearing abilities becomes yet another one. If one of your players has a hearing disability, think about how they would feel if you started using sound effects. Would they feel left out?
With a little planning and creativity, a Game Master could easily add sound to her bag of tricks. As mentioned above, the addition of sound must be done careful, but proper use could add to a more intense, frightening gaming experience.

Fonte: http://www.fudgefactor.org/2005/05/using-sound-in-horror-games.html

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