Hello. I was reading some threads and noticed there are still few topics devoted to the 518 and lots about 558 and 598, and I believe there are people interested about knowing the differences between them, since Sennheiser in the last years is proving to be one of the most reliable and commented headphones manufacturer, and there are people wanting to buying one of them, but don't know the differences between each model.
About the differences, some of them are explained here in this thread: http://www.head-fi.org/t/609634/hd-518-teardown-with-a-shocking-twist , and all of them make sense.
I'm here to say if you're planning to buy one of them and is more prone to choose the 518 because of its lower price, but is worried about getting not-so-good headphones, throw this fear away, now. This won't happen. The old 515 may have its stigma, but this is not the case with the 518, as johan851 showed on his thread.
I've bought my HD 518 almost a year ago, in march of 2012. My previous pair was an HD 201, the best cheap headphones I've ever used, with neutral, crystal-clear sound and great isolation. But it had a huge lack of bass, and this was starting to annoy me, since I listen to a lot of eletronica and I had the feeling I was losing something. So I decided to move on to the next level, the >$100 tier. Since I used to know Sennheiser's sound signature, I didn't think twice and chose to keep with them, and after some research about the 500 series (and hating the 598's colors) I decided to get the 518, since I've thought I wouldn't get much difference with the 558.
At first look, the build looked solid, they didn't have that cheap feeling when touching. Many moving parts with flexible plastic, but no crackling noises, nothing that would make you think "damn, this gonna break soon". So I put them and well, immediate comfort. It quickly took me back to my child days, when I used to listen to music with my father's AKG K501. That always was my reference of comfort, I remembered putting that monstrous thing in my head and feeling like touched by a cloud. But the experience wasn't totally the same because the 518's cushions aren't THAT good. It's a kind of velour, smooth indeed, but not as velvet. And it's so easy to accumulate dirt, hair grips on it like magnet. I always put it back to the box after using it, it's necessary since there's a lot of dust where I live. Well, at least it's not easily decaying and hot like leather, I'm sure these pads will last a lot of time.
After listening to some music with it, my first thought was: now, I DO have bass. And the second thought was: this bass is somewhat muffled. It was superimposed on the sound. But after some hours of use, it started to settle down. So, in that moment I was absolutely sure that break-in is a truth. And with Sennheisers, break-in is pretty fast. On the next day, the sound was much more balanced. That's when I started to feel the beautiful soundstage of these headphones. The instrument separation, the mids now were in perfect place, the bass was still roaring but in an acceptable level and the treble was not sibilant but present, which is awesome since I personally hate strong, overimposed highs. I'm definitely a middle man.
I use them in my desktop with a dedicated sound board (ASUS Xonar DG) or through the iPod with a CMOY amp (Grado RA-1 chipset, a pretty powerful one). Since the 518 is a low-impedance one (50 ohms), amping is not really necessary, for those to wonder about. These headphones accept amping very well, but it's definitely not mandatory as it is with a Q701, for example. Now you all listen to me: after a year of use, I'm 100% sure that the feature that makes the 518 shines the most is the EQing. After trying a lot of combinations, I can say, at least to my taste, that the golden combination on using a Sennheiser HD 518 is low-gain amping with mid-scoop (smiley face) EQ. After listening to music with smiley face EQ for some time and later going back to flat, I was shocked. "How come I was listening to this horrible, muddy sound before and wasn't even noticing?", that was my thought. Seriously, the improvement is something around 30, 40%. I know some people don't like mid-scoop because it gives a "fun", Beats-like sound. But it worked beautifully with these cans, it's great for 90% of music styles. Only with jazz, classical and hip-hop that I need to make adjustments sometimes.
All in all, this was just my personal experience. What I can say for everyone is:
• The Sennheiser HD 518 is worth every penny. May not be good as a 598, but definitely it's not THAT difference, since they have the same driver.
• If you want to get high-end without spending too much, there's no better way. Some guy on reddit who owns a lot of higher-end headphones put the 598, in a ranking, just below the Beyerdynamic T1, which is a mammoth. He also said it's the more comfortable, par excellence. So, if you own a 518, you're not that far from music perfection.
• If at first listen the somewhat muddy sound turns you off, wait. Just wait.
• They're great, but EQing will make'em greater. Amping is not mandatory, but it will help.
• Works great with iPods or any other (good) portable.
• Cable and ear pads are replaceable.
• Sennheiser doesn't need any marketing gimmick. Their products speak by their own.
• Oh, and they're open. They leak a lot of sound (in case you don't know 500 series' nature).
Edited by MarcosRV - 2/22/13 at 9:52am