Sennheiser HD 558 or Brainwavz HM5

Hi. I want to buy a fairly cheap and basic audiophile setup. When it comes to DAC I chose Fiio E10k but still can't decide which headphones should I buy. Sennheiser HD 558 or Brainwavz HM5. I'm going to use them mainly in home for music listening and gaming. I have quite big ears so size and comfort are really important. Now I'm using on board sound card and Skullcandy Aviator headphones, but the headphones are uncomfortable for longer sessions and the sound is not what I'm looking for. The question is will I really hear the difference? If you guys have other propositions with both DAC and headphones in this price range then I would be pleased to hear them.

I actually have a pair of Sennheiser HD 558 among my headphone collection. They are the pair of I use the most out of my bunch because of the comfort, sound and removable cable. The sound stage you get with them is great and they will be great in home use with both music and gaming (which i use mine for). The open backed design of the headphones gives you a nice sound stage which helps with situational awareness in games and also spaces out the instruments out more in music. I listen to primarily metal (Death, Black, Melodic Death, etc) and I find the 558s more enjoyable then my M50s. But when I do occasionally listen to some melodic/ambient electronic music, the 558s hold their own with bassier music, but does not add too much bass where it should not be (does not colour the audio to my ears at least). If you want something with more treble, the 598 is your next best option,  but in my opinion for the money and for a wide range of music listening, the 558s are a great pair of headphones to have. As far as amping, they will help considerably with 558s but it not entirely necessary, but something like a cell phone just doesn't do it for me. I do not own a pair of Brainwavz Hm5s so I cannot give you any feedback on those. 

Thanks! I have one more question. Will Fiio E10k or any other DAC in this price range (under 100$) be better at playing FLAC files (24bit/96kHz) than my on-board sound card, because I can't hear better audio qualiy than 320kbps now. I know that's a stupid question, but I'm a noob when it comes to audio :D

As long as your motherboard is ~3 years old or newer, you shouldn't have any issues with onboard audio.  Only look to get a dac/amp setup if you have actual issues with onboard (buzzing, crackling, lack of volume, etc.)

My motherboard isn't old actually, but I hear some weird noises when I plug in my headphones. DAC will help with that?

First, are you using the front panel audio jacks?  Those almost always cause some noise because you have to run a wire from the back of your case to the front, which can introduce a fair bit of electrical interference.  Try the rear audio ports if you haven't already (an extension cord would be a much cheaper solution than a DAC+Amp).

However, if you get noise issues even with the rear audio, a DAC+amp should pretty much eliminate this issue.

Unfortunately I have this issue on the rear audio port too.

I think I will buy a DAC. But what about headphones. Have you used Brainwavz HM5s?

Haven't tried the Brainwayvz, but I can definitely vouch for the Sennheisers.  For the price, they're pretty hard to beat.

The Sennheisers have the classic Seen veil on them. They have a much more laid back sound than the HM5 which is pretty aggressive with detail. Both are good for their price (though there is a cheaper version of the HM5 linked below), but you should pick which one you want based on the sound signature you want.

They're definitely on the relaxed side, but atm they're my favorite headphones.

Right, and if you are ok with the Senn house sound of laid back, with veiled highs, then they are a great choice. If you want more aggressive detail and something closer to neutral, then the HM5 (or one of the clones like I posted or the Fischer Audio rebrand) is a good choice. It is really just up to what the OP is looking for here.

What do you think about Audio-Technica ATH-M40x?

Loads of bass. If you are into that, then cool. IF you want an accurate, neutral sound, then not cool. The HM5 (and clones) are much closer to a detailed neutral sound than either the HD558 or the M40x from what I know.

2 months ago i bought Sennheiser HD558 and its the best pair of headphones for gaming and music i've ever owned, but then again i am not an audiophile.. but one of the "must have" options for headphones that i wanted was that you can get replacement parts through Sennheiser for the audio cable and earpads for a low price.

Welcome to the club. I recommend trying out the foam mod if you haven't already (and don't worry, you can easily return them to stock if you don't like the change).