Originally Posted by Magariz
While a good EQ is always good it cannot change the sound that the headphones can produce, only maximize their output. I don't have mine tweaked perfectly, but I have tuned mine to what I feel is their best output and the most bass they can get. The bass is good but it is very "hollow", I am looking for more of a punch without sacrificing my clarity. A DSP is not going to give me what I want. My sound card comes with a nice one also. There is a reason that Denon sells $3,000 headphones, that is just out of my budget and those are more designed for pure or refined sound.
Equalization does not "maximize" output, the maximum amount of SPL is always tied to the output impedance, current and headphone efficiency. There is no "+6dB" in any DAC, the signal bottoms out after 0dBFS (that's why it's called decibels from full scale).
Also, while in theory all sound is a sum of sine waves and can be perfectly simulated, equalization can drastically change the sound for the better or the worse, depending on the particular headphones (transient response, ie. square wave test) and the headphone output's impedance (because this affects the damping factor on low frequencies and too low nominal impedances). Your headphones don't seem like a particularly difficult load so I don't see why you couldn't EQ them for more bass successfully. Try adjusting more around 30-100Hz and not too much higher than that because it turrns thumpy and hollow after that. And while some equalizers automatically zero the EQ levels, it's best if you don't apply any +dB settings but instead attenuate all the higher frequencies you don't want emphasized, then just turn up your pre-amp/headphone amplifier. I've seen some volume adjustments just very crudely compress and start distorting the output signal when +dB are applied, so better stick with attenuating unwanted frequencies.
If you really want to buy a new set of headphones, the Beyerdynamic's DT 770 Pro isolate very well, are IMO very comfortable, and have amounts of bass that make you grin. They're also durable and affordable. In another recommendation, the now discontinued Sony XB-700 are VERY affordable and surprisingly high quality/comfort for the price.