Doesn't take "acute," just takes "not destroyed."
I've, at various points in my career, grumbled about various things whining audibly (one particular motion light sensor was defective and right outside my office for a while). The trick to getting other people to believe you ("I can't hear anything... are you sure?") is to wait for a bring-your-kids-to-work day. And ask if they can hear it.
Or, perhaps, if it's bad enough, you don't even have to do that, because the kids will ask what that horrid whining noise is. We did eventually get it fixed after that, but I was quite literally the only one in the hall who could hear it.
On the topic of power supplies, though - Apple has done some impressive work in their small power supplies. The Chinesium clones are similarly sized, they just skip literally every safety feature intended to keep mains voltage out of your USB cord...
And a nice teardown is done here, by the same guy: http://www.righto.com/2015/11/macbook-charger-teardown-surpr...
> Doesn't take "acute," just takes "not destroyed."
It depends. Played in an orchestra, and I've found out that hearing is very different from person to person. Seen people with hearing lower than 20Hz band, or people who can hear a wrong note in a symphony orchestra recording, or people who can perfectly tune their instruments by ear... The list goes on and on.
Our ears' equalizers are not always flat and equal. We can damage them yes, but not everyone starts from the same point.
This is called subsonic hearing, and it is not any blessing. Those who can hear frequencies lower than most often experience pain. It's the low frequencies coming from diesel school busses that are most painful to me, when no one else nearby can even hear the bus at all until it gets close enough. What the GGP is talking about is supersonic hearing, which often also includes that extra detail of pain.
Probably my ears' sensitivity, and that little thing's age (~13 years) are both contributing factors.
Buy genuine Apple chargers, if not for you, then for your dog.
it's a well-studied economic fact that monopolists generally sell higher quality products, and it helps them maintain their monopoly. With their market power and the fat margins they earn, there is plenty of budget to do R&D and have achieve scale benefits. Their optimum-profit product-mix and pricepoints are skewed higher. Nobody complained about IBM mainframe quality, nor Bell Telephone quality.
So, it's not testimony to Apple's prowess, it's simply a cookbook outgrowth of their product differentiation strategy.
You too would benefit from a competitive iPhone market, there would have been an earlier introduction of large screens, cheaper memory options, perhaps getting choices that included repairability, replaceable batteries, microSD cards, etc.
Think of it this way: if Apple was broken into three Apples that compete with each other, the shareholders would not have lost anything that they are entitled to: they'd each still own what they owned before a share of each of the new companies instead of a share in the old. But previously monopoly prices would drop.
Well, that's completely ahistorical. "Nobody ever got fired for buying IBM" was due to conservatism and idiocy on the part of managers and businesspeople, not to mention... you know... IBM's monopoly power and the advantages that went along with that. During the bulk of the minicomputer and mainframe era it had little or nothing to do with the relative quality of IBM's stuff.
What does this have to do with Apple, which has neither the completely captive market that AT&T did nor the overwhelming market control that IBM did?
This is an important consideration all electrical engineers should take seriously when designing products for people. It's a shame many don't.
https://product.tdk.com/en/techlibrary/solutionguide/acousti...
https://www.edn.com/reducing-mlccs-piezoelectric-effects-and...
I will say I have been very impressed with Anker's GaN power bricks of late.