Fixing the ridiculously low volume output of the Vaio Z

My new 2012 Vaio Z was putting out a ridiculously low output on the headphone jack.  Not enough to notice until I took a plane trip, when I realized I couldn't actually hear most of my movies - even at 100% volume.

(This is with some Sony noise-cancelling headphones, which have always worked well for the past 50 hours of flying time.)

Anyway, the instructions most helpfully provided by Antriksh Yadavabout how to boost the volume on the Vaio E series helped quite a bit.  

On my Z, the Dolby enhancements were switched off for some idiotic reason.  Turning Dolby on boosted the headphones output by at least 50%.  Selecting "Movie" mode gave the midrange a bit of boost, good for dialogue.

The studio quality made no difference, the disable all sound effects was already unchecked, and there are no equalization settings on my Z as there are on the E.  But the Dolby tip alone was enough to raise my headphone audio from useless to usable.

If this isn't enough, I might have to get a USB DAC/amp like those described by Lifehacker.  Unfortunately, the reviews are chock-full of audiophile nonsense and quackery, making it hard to know if the things are worth it.  (Hard to believe in the 21st century people are still debating copper vs. silver cables and talk about "breaking in" semiconductor devices, especially when the truth is out there.)

Still, at around $70, it may be worth a splurge if my Vaio still can't compete with 737 engines.  If so, however, I'm still going to be bitterly disappointed this horribly expensive machine can't keep up with a ten-year-old Fujitsu Lifebook.

[Update]:  The Dolby enhancements were enough to boost the Z volume to workable on commercial flights.

However, on my Z, it seems that turning the Dolby enhancements "on" has resulted in a high-pitched air-raid-siren like sound emanating from the built-in speakers.  I rarely use the speakers (mostly headphones) so I did not notice before.

The noise is a thin, tinny, buzzy whine that varies in frequency.  It sounds for all the world like electrical noise caused by a electrical motor (i.e. a fan), but does not seem to be proportional to the fan speed.

Anyway, it is MASSIVELY irritating and renders the speakers utterly useless.  I should post a video or something of this; the irritation factor is difficult to credit until you actually hear this thing.  There are not too many more annoying sounds I have found in my life.

If my work continues to be slow, I may take it in to the Sony store and see what they make of it.  One strike against the "perfection" of the Z.

[Update]:  Sony support suggested to uninstall both Intel and Realtek audio drivers in the Device Manager.  On reboot, they are both automatically reinstalled.  This seems to have fixed the weird whining noise from my built-in speakers.  It did automatically disable to Dolby enhancements too, but re-enabling them shows the whine does not return.