We are often asked why does the ABox have two inputs?
![Image](http://www.e-stim.co.uk/images/2006/internal/abox_inputs.jpg)
The prototype of the ABox only had one, and in fact didn't even have the display the current ABox has. However as the ABox was designed to operate with musical audio tracks as well as dedicated tonal files (see Audio CD), It soon became apparent that being able to listen to the audio you were being stimmed by was useful. You could connect your MP3 player using a splitter cable, but that became an additional connection you had to have and it all became a bit complex. So two inputs were born. Simply plug your audio source into one, and a pair of headphones into the other.
Level Display
The ABox level display was another innovation that came about from play with the prototype. Silence was golden worked wonders, but without any visual display the person controlling the input had no idea if the subject should have been jumping around or not. A quick knob twiddle often resulted in the subject jumping around screaming spoiling the mood and the effect we were trying to achieve. So a level display was created. The 'Perfect' level, to get the most dynamic range our of the ABox is with the input level adjusted just enough for the Red LED to be flashing but not on continuously. With the microphone this can be adjusted with the sensitivity control,
![Image](http://www.e-stim.co.uk/images/2006/internal/abox_mic_control.jpg)
with an external audio source you simply adjust the sound output level control on the MP3 player etc.
Levels
BTW the ABox is designed to work with headphone level outputs (anything with a headphone connection) rather than professional audio equipment line out. Why? Well more people have equipment with headphone connections.
Hope this helps
Si