This is a straight forward tutorial and not much to be said about it but one most beginners would like to get out of the way as it is a very used item in mapping. I know there are many tutorials but I'm making this an easy to find beginners triggering tutorial, With the trigger! (Please dont flame)

So let me get to the beginning.

Alright, First of all you need to think about the scenery you are at, If it's a bathroom, We would maybe want to find a looping shower sound, Or maybe a Once triggered Flushing sound, If your in a sewer, mabey water drops. This plotting can add depth and reality to your map.

So first make a nice little map, No need to go fancy, Unless you are adding this to a map you already made, I've made a sort of box tile type room, Sort of like a bathroom if you will.

The Sound

Now, I want you to go to the entity tool, And select Ambient_generic, This is an Entity that produces sound when told to, Or sound right of the bat, When you start your map. The generally only Sound tool that you need. Now, Place it in your map. Oh look! There is a little yellow circle around the entity, Well, This is... Your sound radius,It's basically how far the player will be able to hear the sound from. You can tinker around with the entity option, (I.E Sound Volume) But i will not go into an explanation of each, Due to the fact that they are pretty self explanatory, Give it a name i used "Toilet." Now look at Sound Name. Once you've clicked it you will see a Browse button show up just to the right. This will bring up another box, With a MASSIVE list of usable sounds. Now you're probably thinking, "Are you serious?!" No I'm not, If you look at the last option at the bottom you will find a box the saiis "Filter" I'd like to thank valve for a moment for putting that in. Now all you need to do is is type in the name you want your sound to be, Bear with me, Vavle has not added all the sounds you might want, If you can't find it, I would suggest doing another search with a different name.

Now, After you've found a sound you like, Name it anything you want. If you're working on a big map, And are using lots of sound, You might want to label them properly, For oginization purposes. For this tutorial i will be using the name "Toilet."

The Trigger

So I'm going to have you create a brush with the trigger texture (Nodraw works too) And press CTR>T, This will bring up and menu And I'd like you to make it "Trigger_soundscape" This will generally mean, Trigger a sound. No need to mess around with the options but feel free to take a look around.

Now, GO to the OUTPUT Tab and near the bottom you should have an ADD option, Click it. Now where it says "My Output Named" I want you to select "OnStartTouch" This means that once the player touches the Trigger the sound will fire, You can also select a plethora of options for this but for tutorials sake stick with "OnStartTouch" (The explanations will be giving near the end of the tutorial)

Now go to the next options "Target Entities Named" and write in the name of your entity, I used "Toilet."

After that go to "Via This input" and from the Dropdown menu, Select "Play Sound" This will trigger the sound to play, When the player Touches the trigger.

And You're Done!

And that's it! There ya have it a working sound trigger, Just for your map. You might want to mess around with it for awhile if you have the time, You can make some really neat stuff.

Oh ya, And here are those explanations i promised you:

Explanations

First of all, Under "My Output Named", It pretty much mean, When the trigger will be activated after an entity walk into it, Or moves into it.

The next one is "Target Entities Named" This is pretty self explanatory, It just generally means What entity is the one that will be targeted, For us we are doing "sound" or whatever you want!

Next is "Via This Input" It mostly means What is going to happen to the named entity after something hit's the trigger.

There is also "With A Perimeter Override Of" But i will not get into it, IF you need help with that Ask the "HalfLife Storm" Studio, Because this entity dose not need explanations until you are of at least Expert standings.

Last of all "After A Delay In Seconds Of" is just as it sounds, It makes the trigger action happen X Seconds after the entity touches the trigger, Or leaves the trigger space and whatnot.

Alrighty Have Fun With You're Mapping Guys!

-Computer-Zombie