harry potter - Why didn't Dumbledore make a sound when he appeared at Privet Drive?

In Harry Potter and the Sorcerer's Stone, Dumbledore appears at Privet Drive:

A man appeared on the corner the cat had been watching, appeared so suddenly and silently you'd have thought he'd just popped out of the ground. The cat's tail twitched and its eyes narrowed.

As far as I know, the only ways to travel almost instantaneously in the wizarding world are apparition, portkeys, and floo powder. I think we can ignore floor powder in this case.

In most instances of apparition in the books, there is a reference to a loud "crack" sound:

With two loud cracks, Fred and George, Ron’s elder twin brothers, had materialised out of thin air in the middle of the room. Pigwidgeon twittered more wildly than ever and zoomed off to join Hedwig on top of the wardrobe.

...

And with another loud crack, the twins Disapparated

...

The door slammed shut and at the same moment a loud crack echoed inside the cellar... revealing Dobby the house-elf, who has just Apparated into their midst.

...

But then, with a very faint pop, a slim, hooded figure appeared out of thin air on the edge of the river... With a second and louder pop, another hooded firugre materialized.

...

With a crack like a whip, Dobby vanished.

...

There was a loud crack, and a house-elf appeared.

According to the Harry Potter Wiki:

Apparition can cause an audible noise ranging from a small faint pop to a loud crack that may sound to Muggles like a car backfiring. House-elves may also Apparate but without some of the restrictions that wizards have. For example, they can Apparate inside of Hogwarts and even the Crystal Cave, where powerful enchantments prevent witches and wizards from doing the same. Also, when they Apparate, the sound is mostly a loud crack.

Finally, according to this answer:

Fortunately JKR provided (most probably unintentionally) a nice explanation about how is this avoided - every time someone apparates/disapparates a loud bang is heard. This bang is most probably caused by the air filling in the vacuum when someone disapparates and the air being pushed out when someone apparates.

I can think of 3 explanations for Dumbledore's silent appearance on Privet Drive:

1. 
   

   He is sufficiently skilled in apparition so that he does not make any sound. This would invalidate part of the answer to the question linked above.

   
   


2. 
   

   He was already on Privet Drive and simply deactivated his disguise, which would most likely have been a Disillusionment Charm.

   
   



3. 
   

   He did not apparate, but used some other form of instantaneous transportation that is not mentioned in the canon.

   
   

So, the main question: Why did Dumbledore not make a sound when he appeared on Privet Drive?

Answer

I was under the impression that those who were more skilled at apparation could do so quieter and even silently.

Now some instances Rowling may have left out mention of pops/cracks as they did not contribute to the story, or they may have been left out simply because there were none/not audible.

Inexperienced / Low Skilled Wizards

We see those that are inexperienced or weaker apparating loudly:

Fred and George:

'Mum,' said George and without further ado there was a loud crack and Harry felt the weight vanish from the end of his bed. (Order of the Phoenix, Chapter 6)

Mundungus:

A loud, echoing crack broke the sleepy silence like a gunshot; (Order of the Phoenix, Chapter 1)

Gasping and spluttering, Mundungus seized his fallen case, then--CRACK-- he Disapparated. (Half-Blood Prince, Chapter 12)

Experienced / Skilled Wizards

While those that are typically more skilled being quieter (or no mention at all of popping/cracking):

Assorted Death Eaters:

The air was suddenly full of the swishing of cloaks. Between graves, behind the yew tree, in every shadowy space, wizards were Apparating. (Goblet of Fire, Chapter 33)

Twycross:

Twycross stepped forwards, turned gracefully on the spot with his arms outstretched and vanished in a swirl of robes, reappearing at the back of the Hall. (Half-Blood Prince, Chapter 18)

Narcissa and Bellatrix:

But then, with a very faint pop, a slim, hooded figure appeared out of thin air on the edge of the river.

...

With a second and louder pop, another hooded figure materialized. (Half-Blood Prince, Chapter 2)

Does the above hint that Narcissa, while more reserved, is more powerful than Bellatrix?

Dumbledore and Voldemort

In the Battle of the Ministry of Magic, we see instances of both Voldemort and Dumbledore apparating.

'Don't waste your breath!' yelled Harry, his eyes screwed up against the pain in his scar, now more terrible than ever. 'He can't hear you from here!'

'Can't I, Potter?' said a high, cold voice.

Harry opened his eyes.

Tall, thin and black-hooded, his terrible snakelike face white and gaunt, his scarlet, slit-pupilled eyes staring ... Lord Voldemort had appeared in the middle of the hall, his wand pointing at Harry who stood frozen, quite unable to move. (Order of the Phoenix, Chapter 36)

In the passage above Voldemort appears completely silently. There is no mention of a crack or pop, and Harry only realizes Voldemort is present when he speaks.

Later in the same chapter we have,

Voldemort raised his wand and another jet of green light streaked at Dumbledore, who turned and was gone in a whirling of his cloak. Next second, he had reappeared behind Voldemort and waved his wand towards the remnants of the fountain.

...

Voldemort, who vanished and reappeared beside the pool.

...

Voldemort vanished;

...

Then he was gone and the water fell with a crash back into its pool, slopping wildly over the sides, drenching the polished floor.

Again, no mention of any sound being made or any of the characteristic CRACK we see with other practitioners.