Ahh yes, nothing treats heart hypo perfusion quite like forcing the heart into overdrive and massive vasoconstriction. Why is the US so far behind on this???
Edit: sorry I was getting technical. Yes it absolutely has a role in cardiac arrest and it's used for this the world over.
It would be very detrimental in a patient with a heart attack without arrest though due to increasing cardiac demand when cardiac supply is already highly limited
For a perfect solution, it would simply be a matter of subtracting one waveform from the other. I suspect both isolated voice and isolated music would have significant "noise" leftover. This would likely be more noticable in the voice due to our increased perception of odd vocal sounds.
Theoretically you could have a projectile with downforce. This would allow you to break that limit. I imagine it's highly impractical though. I hadn't thought of that limit though, good comment!
Perhaps working 50 hour weeks and being well rested would result in faster and more efficient learning than working 80 hours. Yes - you have to do your time, but humans don't learn well sleep deprived.
You could try and force them to work 100, or 160 hours per week and I suspect you'd rapidly find quality of work and learning nosedive.
I think it's worth considering 80 hours is already on the wrong side of that curve.