That's weird... never heard that one before...
Actually we get that all the time! Follow these steps and you'll be on your way to the joyfull blessing that is "sound."
1. Ask yourself this question: Am I deaf? If you answered yes, we cannot help you. If answered no, then continue to step 2.
2. Install Big Red's ATX Patch by following these instructions (quoted from another FAQ post):
3. Whew - you can take a break after all that... or continue to step 4A guy who knows how to install the ATX Patch wrote:FIRST
1. Make sure you have either the "big" or "small" patches installed. They can be downloaded at one of these links:
Right click trespass.exe and goto the Version tab to make sure you've got version 184.108.40.206. If you don't, you need the patch or you cannot change the Draw Distance Variable!!!
You're sure you have version 220.127.116.11 of the trespass exe. You need Big Red's ATX Patch.
1. Head on over to http://www.geocities.com/trespasserhacks
2. Find the Current version of ATX Trespasser by clicking on the downloads link at the top.
3. Save the .zip file somewhere you can find it.
4. Extract ALL OF the contents of the zip file into your Program Files > DreamWorks Interactive > Trespasser folder. Make sure all the directories it creates in your folder are preserved.
5. Run the ATX_Patcher program and select the trespass.exe. ATX will automatically backup your un-edited original version and will create an ATX Patched version in the same folder.
Now you've got a patched exe! Note: that this works generally the same way for the demo.
4. Find the ATXconfig file and open it up in a text editor.
5. Scroll down to [Troubleshooting] and change "DisableA3DdllDetection=0" to "DisableA3DdllDetection=1"
6. Give your patched exe a test run and enjoy sound
Note that this fix is pretty much not garanteed, but it has worked in the past.
That's it! Have fun Trespassing!