Hearing is one of our most important senses. People react to what they hear, and sound can set the mood for your haunt. With so many different sounds available, you will not have any trouble finding that sound that you want. Sounds of Halloween and Haunted Music tapes are available at dollar stores, music stores, and online. We use several different types of sounds in our haunt, theme music for our overall sound at the entrance and sound effects in different sections. Remember when using theme music, what you recognize might not be something your "guests" relate with. The theme from Halloween is a real mood setter, it is easy to recognize, and the guests know what it means! Micheal is here somewhere.
We found that CDs are more reliable and easier to set up, but tapes work well, you just have to have someone to work them. For our overall sound, I use a powerful system with good speakers in many locations. Not only do they hear the sound, they feel the sound. This is very important, it gives it that larger than "life" feel. We use this sound starting about two weeks before our haunt begins. (this is a free haunt that is only open on Halloween) This reminds people what is coming, but keep in mind your location, you might not be able to do this because of surrounding neighbors. We use smaller CD players and tape players in other locations for the theme of the room or area. Keep in mind, there is no use having sound if they can't hear it!
If you have any questions about sound fx,
email me at 
lv2haunt@yahoo.com