It is Simba’s Tiger Roar, not a Lion’s, that can be Heard.
For some, including the roar of adult Simba at the end of The Lion King on this list may seem like an odd decision, but it’s actually pretty interesting: the sound effect that was used to create the sound of grown Simba was actually a sound effect from a lion.
As an alternative, Disney chose to employ the roar of a tiger, because the conventional lion’s roar is thought to be a touch too faint, despite what the MGM lion may suggest. They made a wise choice, but isnt it weird that a real lions voice was used for simba and not for a grown up lion.