The tree-falling problem, while often made out to be a deep philosophical paradox, is in fact a simple example of a basic semantic argument seeming deeper than it is. Although maybe that is, ironically, rather suited to this thread.
The tree-falling problem has nothing to do with subjective versus objective reality. On the contrary, the answer depends simply on the operational definition of 'sound.' If we are defining 'sound' as a physicist might, as waves passing through the air, then yes it makes a sound even if no one hears it. If we are defining 'sound' as a philosopher might, as a phenomenological element; or as a neurologist might, as a certain activation of the central nervous system; or as a psychologist might, as part of a certain behavioral process, then the tree does _not_ make a sound if no one is around.
I guess you could argue that what's really being asked is "If a tree falls in the forest and no one is around, does a tree actually fall in the forest?" which admittedly would be a deeper problem related to reality. But that is, however, _not_ what the riddle is asking.
I swear I didn't just try to change the topic. I swear.