Hi there, This is not a homework question. I am currently conducting a visual perception experiment with a professor. We are trying to find out how duration of a sound presented concurrent with a visual stimulus affects the localization of the visual stimulus which participants have to localize. The experiment protocol is as follows. 1. There is a a fixation point on the screen that subjects stare at. 2. They click a mouse and a target appears to the left or right of the fixation point (which dissappears) and the participant has to make a saccade (eye movement) to that target. 3. Around the same time a stimulus is briefly flashed on the screen concurrent with a sound (white noise) played for some duration (8 ms). 4. Subjects have to use the cursor to click on where they think they saw the flash occur. The issue is with step # 3. We want to make sure that the sound is perceived to emanate at the location where the flash occurs and not just coming out of both speakers. Using stereo doesn't work because that just plays the sound from either the right or the left speaker. Here's to show you what I mean: FP--------Flash 1 1 1 Head FP = Fixation point on the screen. Participant's head always faces straight (we have a bite bar to keep their head stable) The visual stimulus is flashed some random degrees to the right of left of the FP (above it's flashed to the right). I am looking for a function that shows amplitude (loudness) decreasing as a function of increasing distance (between head and flash). I don't where to start since I only have a introductory background in Physics.