Well animals can hear sounds at frequencies that we can't, so the cutoff shouldn't be when we can detect something. But in that case, do we set a cutoff on the

Well animals can hear sounds at frequencies that we can't, so the cutoff shouldn't be when we can detect something. But in that case, do we set a cutoff on the lowest/highest frequencies that we know some animal can hear? Then we might discover something later that increases the range, what do we do then? It just makes more sense to generalize sound past what's actually audible, in my opinion at least.