I got my storage cubes for the attic craft space assembled. Two of them are these open cubes I turned on end and left the backing off. That way they “frame” my speakers and I don’t have to cut holes for the wires. They are by Foremost and I ordered them from Staples. I like this brand because they are light enough in the carton for me to carry them upstairs, they are easy to assemble, and the particleboard is soft enough to drive a screw in with a normal screwdriver if the drill battery is dead. The drill sure speeds things up, though.
Unless I’ve mismeasured, the Container Store has shelf baskets that should fit nicely above the speakers. I hope I can get by there this week!