[satow]

I got my first pair of Sennheiser HD 518 and boy, I really like them. Extremely comfortable and neutral sounding. I don't know why some say they are warm or dark sounding. Very clear detailed treble and good bass. Not too expensive for the awesomeness you get.

 

[satow]

Does anyone else use these headphones?   I was wondering what amp they use it with.

 

[Beyakusenn]

I got my first pair of Sennheiser HD 518 and boy, I really like them. Extremely comfortable and neutral sounding. I don't know why some say they are warm or dark sounding. Very clear detailed treble and good bass. Not too expensive for the awesomeness you get.

Congratulations! You have purchased headphones that deliver great value for money.
 
The HD518 were my first step into the world of good audio. Back then I thought nothing could sound so much better than the HD518  that it might be worth the price. I was wrong of course. Back then I also believed the HD518 sounded natural and neutral. After listening to my later purchases (AKG K550, Senn HD580, HiFiMan RE-400) I learned that the HD518 had a sound leaning towards the warm and dark side.
 
Now I own a Beyerdynamic T1, Beyer t51p, B&W P5 S2, Senn HD580 and the HiFiMan RE-400. Looking back, the HD518 was the best introduction I could have had to HiFi-headphones.
 

  Does anyone else use these headphones?   I was wondering what amp they use it with.

These headphones do improve when you use an amp, however the improvement might be greater if you purchase the HD580 =P
Looking at it as an investment for the future, you might want to look into Musical Fidelity X-can V3. It gives you the possibility to play with tubes while keeping Solid State characteristics.  I had one of those myself (with Philips NOS tubes) and it sounded great with both my Senns.

 

[satow]

Thanks for the reply!   I haven't tried the other headphones you listed.   I guess I was trying to find one that was universally good for all audio types.  Are there specific reasons why the others you listed are better?   I almost bought the Sony MDR7506, but read that the studio monitoring headphones are okay, but not great for music listening.

 

[Beyakusenn]

I think you made the right choice. The HD518 sounds great with many different genres. It's good to gradually get used to listening to music with good audio equipment. Listening can be trained and the more things you try, the more you learn.
 
Something very important is your source. Do you listen to music using your phone? An i-pod? A DAP or DAC? Your computer? if you use the standard soundcard in your computer or just your phone, you won't get the best out of your music. I have a Colorfly C3 and a Fiio X1 for on the go. My laptop has an awesome sound card so an external DAC would do no good. As a media player I use Winamp with WASAPI. WMP is no good.
 
Also very important: do you listen to mp3 files (lossy) or to lossless music (FLAC/WAV) or both? If you listen to mp3, do you pay attention to the bitrate? If you really want compressed files in mp3, 320 kbit/s is imo the only way to go.
 
Comparing the HD518 to the other headphones I own / have owned I can say this:
 
AKG K550: this is a more neutral headphone than the HD518, but a tiny bit on the bass-light side. It has a very accurate bass though. More so than the HD518. The mids and highs are nicely balanced. Some people seem to have problems with a treble peak. I didn't. Both headphones are extremely comfortable. The K550 has an incredible soundstage for a closed headphone at its price range. The soundstage is different from the HD518 and I can’t remember exactly how it was different, but I liked both equally.
Sennheiser PXC350: For on the go, these are really handy. The noise cancelling is good,  they fold flat in a carrying case and the sound is very good. They are large though and the sound is not as good as the HD518.
Sennheiser HD580: I bought these together with the Musical Fidelity X-can V3 with Philips NOS tubes for just €200. That's a steal! The sound is not dark at all, but it still has some warmth to it. Overall I'd say this is a neutral, natural sounding headphone. It's more detailed, has a larger soundstage, better imaging and it is even more comfortable than the HD518. Yes this is really a step up. It is a discontinued model, but spare parts are available everywhere because it has a large family with two younger brothers that are still in production (HD600 and HD650). The HD600 is basically a HD580 with drivers matched to have the same characteristics left and right, new grills and new paint.
HiFiMan RE-400: these are in-ears so it's not really fair to compare them, but if I have to: the RE-400 is very neutral and natural but has an in-ear soundstage, therefore the HD518 wins sound-wise. The RE-400 are extremely portable though, even for in-ears, so I'll keep using them often.
Beyerdynamic T1: I tried different headphones before upgrading from my HD580 and anything less than the T1 wasn't really that much better compared to the HD580. AKG K702, Beyerdynamic DT880, Sennheiser HD700, none of them was really an overall leap in performance. The Beyerdynamic T1 was the leap in performance I was looking for. It is more detailed than the HD580 over the whole frequency rate, more neutral overall, much faster. The extension, detail and structure of the (sub-)bass is amazing. I won't be needing an upgrade for a while (and I can't afford one anyway). It was much more expensive than anything else I have though.
Beyerdynamic t51p: This is a headphone for on the go. Not really comparable with the HD518. It has a bass hump (which works really well in noisy environments), still it retains great speed and detail over its whole range. It is clear that it has T1 genes in it (Tesla technology). The mids are terrific and the highs well balanced. Soundstage is very dependent on source though. It can be great, but with for example a Sansa Clip+ the soundstage is below average.
B&W P5 Series 2: I already had the t51p and knew I liked it better, but as warranty for my malfunctioning C5 in-ears I could get these for €150 less! so I couldn't miss that chance =)
 
By the way if you like neutral sound, don't go for the C5, those are really dark. Go for the RE-400 instead. Better sound for nearly half the price.