I am perhaps not in a position to comment on this, BUT First I suggest youto hold it differently, find the nodal points usually on above to right or left of the soundhole about 5cm in. Grab it with one finger on each side and tap once and let it ring till no sound remains, hold your ear on the other side of where you tap and listen. IOt might be the how the video takes the sound but I could not hear much of a ring or ping or whatever. how thick is your top ? But again I have not the experience to comment except for the few tops I have made so far "3" haha. but they ring like crasy though. about 3-4 seconds. , tap mostly on the lower bout. and move around. if its dead then move with the fingers your holding the top with, just a cm here and there untill you find the perfect spot.
Any comment on my comment is great learning experience
Lars.