You may need an oscilloscope to measure trigger and audio timing, a gaussmeter to objectively characterize the level of electrical noise in a space or something else along these lines.  If you are looking for something you don’t find here, let us know.  We recently added two new testing equiptment products made by Cambridge Research Systems, Ltd.  The SpectroCAL MK11 spectroradiometer is a cost effective reference spectroradiometer with software for vision science.  It is ideally suited for characterising computer monitors and projectors, including CRT, LCD, DLP, and even OLED displays.  We also have a ColorCAL MK11 colorimeter which is a calibrated and affordable colorimeter performing better than a spectroradiometer for gamma corre ction.  ColorCAL helps to make display linearization automated and fast.