Which turtle beaches do you have? Are they 5.1? If not I would highly recommend the DSS module thing because that will give you a 100 times more of an advantage than any EQ settings.

Turttle Beach sucks man.  Get these

http://www.headphone.com/selection-guide/beyerdynamic-tesla-t1-balanced.php 

you will be hearing hrz low as .00000001   it shakes your body.  you migh c*m. 

i use px21 and i have had them since mw2 they were very good at soundwhoring in mw2 with sitrep on they were ok in b-ops not as good as mw2 but in mw3 its a little harder u can soundwhore but no were as good as other cods like #sworndeath says i would just try them out in other cods first get a feel for the sound set up u like best and ppl who say there crap no good what ever they are right if they can buy top end ones but for the price u pay for them they are very good

I have also heard that most people regret buying TB's, mostly because of build quality. I have had my PX5's for a year now and can safely say that they are much better quality than the cheaper TB's. I have not had a single problem yet, then again, I treat my equipment with respect as I payed my own $300 (yes it is that expensive in Australia) for the headsets. I have heard good things about the Astro's too but never tried them myself.

I took back my TB5's though I got a few kills by sound whoring, I didnt see a noticable change in game play, and infact I felt like they hindered me having some heavy phones on my head, I feel I do better without a headset

I got the PX5 as well and I'm pretty happy about it. Anyway, I'll explain what I did to find the presets that suited me best:

1. Go to the TB website, login and download all the presets that seem interesting to your playstyle.

2. Find a recent match in theather mode where you are in a spot with an enemy around, of which you want to hear the footsteps of (lockdown always works well because of the wood they walk on). If possible, try to find a sequence which you can repeat over and over by pressing the back button.

3. Connect your headset to your pc (while still connected to PS3). Load various presets into your headset while you listen to the sequence mentioned just above.

Try out the different presets to find the ones that suit you best. Write the ones down that give you the best results and start messing with those. Important note: pay attention to the effect the preset has, does it just increase the total volume or does it enhance the footstep noises.

I'll give you my favorites (from TB site) as listed in my PX5 Advanced Sound Editor:

Master: [PS3]Superhuman Hearing

Mic: any

Chat: any

Game: [DH]MW3_SuperSoldier

Master: [PS3] MP Footstep Focus

Mic: any

Chat: any

Game: [DH]MP Footstep Focus

It (of course) comes down to preference, if you're not happy with the results you should return them. I do have to tell you, in MW3 the footstep sounds aren't very easy to hear. If you pop in Black Ops or MW2, it's a world of difference and you can hear literally everything and everyone.