"If a tree falls in a forest, and no one is around to hear it, does it make a sound?"
	Have you ever tried to solve this riddle?  
	I don't mean in the cheeky literalist way, where the answer is yes because a tree falling must produce a vibration of some kind, and sound can be defined as a result of vibration.
	No, the intent of the riddle is to consider the provability of the circumstances surrounding an event where there is no evidence nor witness.  It's a riddle because it's common sense that a sound would happen without an observer, but that that assumption could potentially be in error.
	So what if I say yes and you say no?  Before addressing the conflict, take a step back and ascertain whether there even is a conflict.  Did we imagine the same tree?  The same forest?  Because the riddle is such a simple line of text, the details are left entirely to imagination; I suggest that, no, the chances of us imagining the same scenario are infinitely small.  Effectively there can be no singular correct solution because there is not a singular scenario to reference.
	Now, I have to go into why any of that matters.    If you look at the wording of the riddle, you'll see why it is not sufficient to accept a single subjective conclusion.  "does it" may as well be "will it", which is much different from "can it".  This means that it must be proven with no exceptions.  Naturally, this leads one back to the literalist realm of answers, but I'll ask you to ignore that for now in favor of examining a different idea:  how real must the scenario be?
	With heavy reliance on imagination, one could easily imagine a set of extravagant - even supernatural - circumstances that could force a certain answer.  The riddle does not exclude such things explicitly.  So the riddle is impossible to solve, because it will always be possible to imagine at least one scenario for both "yes" and "no".
	Implicitly, you're supposed to think of a realistic scenario, of course.  However, imagination must be a factor because it is linked to observation, which is absolutely a factor.  We are not machines; we process and configure our sensory data into observations - likewise we can imagine an event without direct sensory data while being able to imagine what the sensory data from the event would be.  So what makes something real?  I will posit that an objective reality is not necessary to validate the quality of "real"; that a daydream is just as real as the tree and the forest featured in this riddle.
	Even if the premise scenario were changed from text to a mute video, answers could vary.  Even if you and I both stood watching it in real life, our answers could vary!  It sounds silly - obviously if there are multiple direct observers, it's not even a riddle anymore, just a comparison of factual data.  Let me put a twist on that.  Let's say there are 100 observers for this real event, and that you are 1 of them.  Afterwards, everyone is asked if the fall of the tree made a sound - and all 99 of the others say "no" while you say "yes".  Would you doubt yourself?  Would you doubt them?  Something is clearly not right.  But who is wrong, why are they wrong, and how can anyone prove it?  It's not actually provable without reading everyone's minds.  No, I will suggest a simpler explanation to circumvent this problem:  the existence of objective reality is entirely unverifiable because everything must be an interpretation of one's subjective reality.  In other words, there is only a problem when one asserts that all observers of an event must have the exact same experience - further, that every observer can have wildly different and contradictory experiences from the same set of stimuli.  ...And that is from a scenario of minimal imagination.
	If you think about this for a minute, it might not seem very useful.  I will add another metric:  belief/certainty.  If you and I observe an event and conflict in our interpretations, but I am less certain of my interpretation than you are of yours, then your reality is more real than mine is (as far as that event is concerned).  This does not necessarily mean that your subjective reality is closer to objective reality than my subjective reality, but that wasn't a goal anyway.  So what does it mean when your certainty exceeds mine within (relatively) the same boundaries?  It means that the determining factors of what is reliably real to you were more thoroughly crystallized than the similar factors were for me.  One common interpretation of what this means is that the reality you experienced has more details that can be recalled than the reality that I experienced.  So it is possible to dismiss my answer of "yes" based on my inferior certainty (whether this is wise is another matter).
	Finally, while it's simple enough to place two beliefs on a scale and compare them, what of the earlier example of 99 contradicting realities?  To make the same dismissal based on certainty, it is not sufficient to make 99 individual comparisons.  The exact formula I cannot properly suggest, but let's speculate a simple sum in order to complete the point.  The total sum certainty of all 99 contradictions would need to be inferior to the certainty you have in your reality - a tall order.
	In loose summary, the answer to the riddle is "Whatever I say the answer is, and the burden of proof is on everyone else, but only to believe I'm wrong more strongly than I believe I'm right."