It is not a very high frequency and 12 dB is equal to silence
I suspect you are right in that some machines are more audible than others in the higher frequencies. 'Coil whine' has been extensively discussed elsewhere and provides a perfectly plausible explanation given the lack of moving parts. I guess the exact frequency has never been proven. Does anyone know what frequency this whine is on, as that should help target the part?
High frequency hearing is incredibly subjective and very easily damaged. Advancing age will definitely show a positive correlation with a diminishing ability to discern higher frequency sounds, but that relationship certainly won't be linear.
Now personally I see this as a good thing, as potentially, I can actively deter random pets and 'the youth of today' from using my stuff! j/k
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I found a tool producing increasingly high frequencies and tested me (I am 69),
At about 10 KHz I could hear nothing more.
This should be the case with most people at my age.
I then found 2 Apps measuring in dB the sound around.
I am aware that the mike of my iPad 2 is not the ideal equipment but I had nothing better.
I could not in a silent room obtain that the dB needle should show less than 30 dB. Obviously some noises from outside or inside, even not loud at all, translate into such a value.
My quite breathing made it jump about 8 dB. That proved the tool was working although certainly not any high piece of sound level measuring equipment.
What that all means?
First that the noise recorded by different users complaining about a "noisy" nMP must be in my humble opinion of just a few KHz. Otherwise I could not in any way hear it and I DO HEAR THE RECORDED FILES!
Second, if Apple offers their nMP stating no more than 12dB noise, that means for any practical use SILENCE!
To sum up, the noise that at least some nMP make is by no means so high that age might be the decisive reason why some people hear it and others don't.
And if a nMP keeps the spec of Apple of no more than 12dB, then it is truly silent and dead quiet (or the opposite order or words if somebody prefers).
Whoever hears from a nMP an annoying sound, has received a machine with a clear and undeniable hardware fault and has a legitimate right to ask for repair or replacement until the 12dB threshold is kept, in which silence is a reality.
To argue that this causes unnecessary expenses to other buyers of nMP (as some genius has written) is absolute nonsense.
Every repair under warranty causes some expenses. Therefore let's abolish all warranties and avoid in this way expenses for other customers.
Do all agree with this wise solution????
If a giant like Apple cannot resist the ridiculous percentage of losses caused by repairing a relative small quantity of faulty computers in the best and most expensive class they offer, then let's start to collect money to help them survive!
