QUOTE (Seren @ Jan 11 2013, 06:20) <{POST_SNAPBACK}>
Only thing I can suggest is to look for sound drivers for the laptop or turn off any added effects the OEM may have activated.
Or possibly on the old laptop you had some effect activated to suit your tastes which is not active on the new laptop.
For example in Windows 7, there's usually something like:
Volume Context Menu/Playback Devices/[specific device used]/Properties/Enhancements/Bass Boost (or possibly even Room Correction)
that can affect the frequency response as well as Disable All Enhancements.
(On my laptop, I have a separate entry for headphones, but the Speakers setting controls both headphones and speakers, so try something to check you're adjusting or checking the right 'playback device')
I guess we can eliminate high output impedance trying to drive a low-impedance load, because your Turtlebeach Z2 are 32 ohm impedance and the earbuds are likely to be similar, which ought to be fine.
Does the Z2 have a combined microphone and headphone 3.5mm jack plug? That might be a potential problem in a standard stereo headphone-only socket perhaps.
Also there are some audio devices specifically tailored to be non-flat (e.g. ~20 dB bass boost present in one 'stylish' CD player's headphone jack & speaker output with no adjustment available).
A loopback test (or input to a PC soundcard with a line-in port - usually lacking on laptops) might be revealing if there's a problem with your settings. You could compare the spectrum of captured and original audio or even run a RMAA test.