About the mid nineties our Haunted House was going full steam and we were trying different things. One thing that had worked for us was using a Quija board and making it move around using magnets. It was a cool looking effect (not magic, just spooky for a witches lair). With that success we were working on a chalkboard that had "Death" written on it and a piece of chalk (with a metal pin inside and magnet beneath, the magnet being on an old phonograph) that would move around the chalk board. This also looked kind of cool for our witches lair so we added sound to the effect, the screeching noise of someone writing on a chalk board. When we tried it out it looked and sounded great, but when we used it in practice, the sound was worthless, it was completely drowned out by other sounds in the haunted house. The chalkboard did not look as good without the sound so we scrapped the whole idea after a couple of days.
With the conditions of a seance or even just general closeup, the sound idea does work and it really works well. Although we have abandoned our moving chalk for a set of spirit slates, the effect is almost the same. Now the drawback in working with a closeup audience is finding a set of spirit slates that does not talk much, we tried about 6 different ones with varying degrees of success till we found one at Fab Magic that we decided to run with. The Fab Spirit Slate (in my opinion) is the quietest gimmick out there so if you are looking at closeup or want to use the sound effect (which requires lack of background noise) you might want to consider the The Fab Spirit Slate.
The issue with spirit slates in general is that chalk slates are not nearly as popular today as they were in the past (this is easy enough to get around with a little patter about the past). Also when it comes to spirit slates and magic, it is really half a trick - a revelation - you have to provide the front end of the effect.
However I think the positives far outweigh the negatives. The spirit slate is like the black and white horror movie of magic - it does not have the blood, gore, or special effects of the newer movies but has the more elegant atmosphere of a Vincent Price movie. The spirit slates are very easy to do and can reveal anything you like, even gibberish. The Fab Spirit Slate also has a feature that will automatically line up the slates for you (if you are a magic purist and don't like this its not a problem, simply turn the slates over and they will work like a standard set of slates).
The sound of the chalk is optional and there are several ways to do this.
In the past (seances before electricity), the Medium would generate the sound by using their toes and writing with chalk on the bottom side of the seance table. Ipod technology solves this problem easily so modern magicians need not have to remove their shoes. The one I use has the volume turned up to make sure that the camera microphone would pick it up, but usually it is much more quiet, just enough volume to let them know something is going on. If you use an Ipod for this remember to put the sound effect in its own playlist, otherwise the Ipod will play the next song alphabetically (Johnny Mathis' "Chances Are" in my case). I use a one minute delay and am usually able to get within a few seconds of the sound effect.
Two slates 8" x 9" are displayed and locked together. A volunteer is asked to select a playing card from a deck of cards and return. The "spirits" know what card you selected! Upon opening the slates there is the selected card written in chalk!
These slates are made here in our studios. We use only the finest materials in their manufacture. Two different styles available. Our special magnetic locking frames - $55.00 and Hinged version $60.00