Quoted from mmuglia:
I saw this posted and had to give it a try. I installed the 4.7k resistor and there is definitely more bass, but overall, the sound is very muffled and it sounds like shit! Adjusting the volume of the game only made it sound worse. Maybe a different value resistor would be better. I took the resistor out after 1 minute of gameplay.
Thanks for your honest feedback, I appreciate it. I guess the best (and only?) other solution is to use pinsound... not cheap thought.