I have to erect some shelves: 22 inches wide, supported at the ends by heavy-duty bookcase-type uprights and brackets. This is to hold fairly weighty audio-video equipment.
Given an equal thickness (18mm? 20mm? More?) and a choice between MDF, plywood, veneered chipboard, solid timber or something else, would any particular material be preferable? 22 inches isn't much of a span, is it? And appearance isn't really a factor.
Many thanks.