2011 MBP- Poor sound quality through headphones? (After EFI update?)

[ReanimationN]

Hey all, how would you rate the sound through your 2011 MacBook Pro's headphone jack?
After swapping back to my 2009 Compaq/Windows laptop to use ArcGIS for a while (and to go through my old iTunes library while working), I noticed something odd.. my old Windows machine seemed to produce far greater sound quality through headphones than my MBP. After swapping back and forth between the two laptops, and listening to the same minute of Deadmau5's 'Strobe' on both machines multiple times, it became apparent that my MBP had muted, dull, flat sound when compared to my Windows laptop, which produces amazing sound through the headphone jack.

No matter which song I tried, or which headphones I used, the results were the same. Using Windows on my MBP has always generated slightly different sound to OS X so I left it out of my comparisons (it was always nearly identical to the sound produced by OS X though, so it was never all that noticable). I swear this wasn't the case though when I first got my MBP (a recent exchange for another unit with a faulty graphics card), it sounded the same as my Compaq, but after applying the recent EFI update, it now sounds quite different (although as I hadn't been using either laptop much around that time, I probably wouldn't have noticed for a while if I hadn't used the Compaq).
Could the EFI update have caused this, or has something happened to my MBP's headphone jack? Or do the 2011 MBPs generally have poor sound through the headphone jack and I missed out on that fact initially?

 

[eternalife]

I was about to post a new thread but came across this post in my search.

I just bought a new set of premium headphones (B&W P5s) - Premium to me anyways. I downloaded a 'Burn In' CD from here: http://binkster.net/extras.shtml#cd

I was running it through my headphone jack on my 3 year old crappy Dell laptop and listening to the different frequencies through the headphones - intersested in seeing how they handled the lower frequencies (40 Hz - 90 Hz). Surprisingly the headphones (and Dell laptop) sounded very good at this range. Well I had to take my Dell to work so I transfered the burn process over to my 2011 MBP. I started up the burn in process via iTunes and started listening just to make sure it was playing before I left for the day. Well, it was playing the tracks in this frequency range (beginning of the CD) and they sounded terrible (a lot of noise with very little evidence of the actual track sound). It wasn't until I got to around 100 Hz that the sound settled down and I could here the track.

What a disaapointment. Based on the lack of comments on this original thread I assume not too many people have had sound quality issues with their MBP or they just haven't checked. Can anyone else confirm they have issues (try using the tracks listed in the thread I included above)? I'm trying to determine if it is just my computer or all MBP (releated) computers. In other words I don't know if I should take it in for service or just accept the issue as 'the way it is'.

Any help ?