[goldenSHK]

  I have both pro 900 and x1. Two of my favorites that I have kept after buying and selling MANY others.
 
The pro 900 is an EDM headphone. It has amazing fast bass, and sharp, clear clean highs. It's warm in the bass and bright in the treble at the same time. I've found I like to EQ the very top highs down a bit, to give it a touch smoother top end. But I also listen often without this EQ.
 
But yes, this is a sharp sounding headphone, that puts lots of detail out. It's an incredible headphone for EDM, and anyone who likes the genre MUST try it, IMHO. The tightness of the bass and punch is just fantastic.
 
The X1 is a great headphone as well. Comfort is excellent. Bass is deep and enjoyable. Highs not as sharp and extended and emphasized as in the Pro 900. Again, as great headphone for EDM. I actually use my Pro 900 short cable with the X1. It's my favorite cable I've found for the X1... the X1 also has a very nice soundstage.
 
The X1 isn't as fast, sharp, aggressive, and intense as the Ultra-sone. It's a smoother and more relaxing ride.
 
For bass-heads who can tolerate somewhat sharper highs, Pro 900 is a dream come true. Probably my favorite HP I've ever tried, including ones costing many times more. It is a unique sound, but boy is it fun.
 
The X1 is very special as well. If I had one annoyance, it flattens my hair (with that massive headband!) in a way I really hate, and I always have to adjust my hair after I'm done listening. But sound wise, incredible value for the price. I really think it's underpriced for the quality you get - both sound and comfort.
 
These are both headphones with a bass emphasis. The 900 has the highs emphasized. 
 
Try them both, both are excellent and well worth it. Not to mention, they aren't at all hard to drive either.

How much bigger of a soundstage does the X1 have compared to the Pro 900 even though the Pro 900 have S-Logic? I imagine the Pro 900s still can't compete since they are a closed back. 

 

[TWerk]

I'm terrible at describing soundstage. Just a disclaimer.
 
I think the Pro 900 are very good for a closed back. I think it's called imaging, but they can throw sounds around the stage where you feel you can locate the direction it is coming from. It's a quality I really like about them.
 
If you look up the song "Lucy" by Seven Lions, you will get a good idea of this quality. It's like some sounds come from behind, some from upper right, sweeps right and left, etc.
 
I think the "stage" of the X1 is somewhat bigger, but the imaging (direction sounds come from) isn't quite as precise and defined as the pro 900. 
 
Nevertheless, the X1 sound rather expansive for a headphone. Probably due to in part, as you have said, them being open back.
 
Another difference: X1 don't have as good resolution as the Pro 900. The 900's are clearer and like 1080p instead of 720 in terms of pulling out detail. The bass of the X1 is looser and has a slower decay than the 900 which simply does it's thump cleanly and powerfully, and very tightly.
 
The 900 would be the more analytical headphone, the colder one, the sharper one. The X1 would be the warmer and more smooth "rounded" headphone. Sound is more smoothed down and less sharply defined and separated in comparison.
 
I highly suggest you listen to the song "Lucy', anyone with any headphone should. It's a really cool track with the way the effects and production techniques are done. The Pro 900 kills it, sounds insane.
 
To know where my biases lie, if I could only ever keep one of my headphones, it would be the Pro 900, no doubt. The X1's are very good, but not "as good". Pro 900 was also my first big boy headphone, and I've had it longer and put more hours on it than probably all the others I've tried combined
 
 
 
 
 

 

[TWerk]

  X1 should be best open "basshead" headphones available and that says pretty much everything. I personally don`t consider them as basshead HPs because with upgraded cable and proper matching amp/dac it can turn into pretty balanced sounding while still able to play deep powerful bass when recording gives/needs it.
If You wish to go open-design "basshead", then X1 is probably the way to go.

 
The Ultrasone 2500 puts out big bass as well and it is an open back. It has a mid bass emphasis though, much like the 900. It also has a pretty metallic sounding treble. It IMPACTS harder, where the X1 reaches deeper and lower and (to my ears) has more reach than the 2500. That being said, I'd still recommend the X1 over the 2500.
 
 
@goldenSHK you should deff grab an X1. It's an excellent headphone, well worth the purchase if you're into headphones with great bass.

 

[goldenSHK]

   
The Ultrasone 2500 puts out big bass as well and it is an open back. It has a mid bass emphasis though, much like the 900. It also has a pretty metallic sounding treble. It IMPACTS harder, where the X1 reaches deeper and lower and (to my ears) has more reach than the 2500.
 
Nevertheless, @goldenSHK you should deff grab an X1. It's an excellent headphone, well worth the purchase if you're into headphones with great bass.

I'll grab the X1s for sure. I am glad there is at least one other Pro 900 fan on Head Fi besides me. It seems like literally every other person and their grandma disdain almost all of Ultrasone's line. I definitely want to know how the X1s compare to the Pro 900 and HE-6.
 
I just listened to the Seven Lions you linked, it is mesmerizing on the Pro 900 with a good DAC. But then I tried it with my HE-6 stack and it is just as great but for different reasons. Less bass, but feels much more real and visceral. 

 

[TWerk]

Isn't that an awesome track?
 
I wish more producers would make songs with those kind of production effects. It's just neat, like audio candy for your ears.
 
What DAC are you using for your 900?

 

[CoiL]

 
The Ultrasone 2500 puts out big bass as well and it is an open back. 

Ultrasone 2500 is semi-open design.
 

I wish more producers would make songs with those kind of production effects. It's just neat, like audio candy for your ears.

Nothing special about that song and imho it`s not so good mastering.
 
For bassheads, try this song with great mastering: https://www.youtube.com/watch?v=IddDWBpkzYg

 

[goldenSHK]

  Isn't that an awesome track?
 
I wish more producers would make songs with those kind of production effects. It's just neat, like audio candy for your ears.
 
What DAC are you using for your 900?

It is indeed a very well mastered track. 
 
I'm currently using my friend's Geek Out 1000 and the amp/dac is amazing. I really want one for myself, but the only issue I have with it is that it gets insanely hot. But it pairs really well with the Pro 900 and sort of HE-6. The hifiman is a tiny tiny bit underpowered to my ears, but honestly I probably wouldn't be able to tell the difference in a blind test. It's a great gadget. 

 

[TWerk]

  Ultrasone 2500 is semi-open design.
 
Nothing special about that song and imho it`s not so good mastering.
 
For bassheads, try this song with great mastering: https://www.youtube.com/watch?v=IddDWBpkzYg

 
Haha, I own that album, by Eskmo. It's on my ipod. Cloudlight is a cool song. I remember being impressed when I first heard it too.

 

[CoiL]

Seems that X1 is now discontinued. Sellers have started listing them as discontinued by manufacturer . 

 
Get them while You can. 

 

[waynes world]

  Seems that X1 is now discontinued. Sellers have started listing them as discontinued by manufacturer . 

 
Get them while You can. 

 
I don't think they should discontinue them. They are different enough from the X2's, and I think that there are probably many people who would want to buy them (especially for a price lower than the X2's).

 

[eac3]

amazon just jacked up the price on the x1

 

[goldenSHK]

   
I don't think they should discontinue them. They are different enough from the X2's, and I think that there are probably many people who would want to buy them (especially for a price lower than the X2's).

Calling it now, the X1 discontinuation will be similar to Denon's old line discontinuation. People will prefer warmer sounding headphones to the current alternative and will have to look at the used market now. 

 

[xDezor]

Seems that X1 is now discontinued. Sellers have started listing them as discontinued by manufacturer . 

Get them while You can. 

Sad day

 

[hk6230]

Well, at least I had one.

 

[NinjaQuick]

I'm working with support to get them replaced.