Had a quick listen to these today. Sound wise they were very nice, solid bass, good mids, and nice detailed but not overly bright treble with a decent sized sound stage.

Issues with sensitivity (I was turning them up to 2/3 or higher volume on my Nokia 920 phone) and comfort (to small for my ears to fit in the cups) ruined my aspirations of these being a good portable option for me.

if you don't mind an on ear type cup and have a more powerful portable source or carry a portable amp then these should be looked at closely as they do offer a very good sound experience.

I think there might be a different driver in the HD 360 Pro than there was in the PX 360.
http://www.head-fi.org/t/615647/modding-px360 found this thread on modding them (Removing some isolation foam to boost bass)
comparing this: http://img833.imageshack.us/img833/4829/dsc03516x.jpg
to this: http://cdn.head-fi.org/e/e2/900x900px-LL-e209211e_IMG_0641.jpeg
It's something different, but that could also be the difference between left and right earcup. It could also just be the housing of the driver that's changed. It doesn't look bigger or smaller.
 
Oh, and the names for this casing? Glob globbit, there're many! PX 360, PX 360 BT, PXC 360, HD 360 Pro, MM-500-X and MM-550-X.
I'm not too sure about all the differences.
Wired: PX 360, HD 360 Pro.
Wireless: Everyone else, optionally corded (Does the mic/remote still work corded?)
SRS: PX 360 BT, PXC 360 BT, MM-550-X
ANC: MM-550-X (Anyone else?)
 
I emailed Sennheiser in a couple of ways about it, it was mostly a fanmail, though.
 
Slightly off-topic: Anybody here who used these, who know of a better/bigger/more fun sounding alternative with the same kind of fit? I've been out trying stuff for a month, trying to find a replacement for my broken PX 360s (The wire snapped somewhere after 2.5 years, since their inception), but nothing isolates just as well.

Recable your PX360 instead.  Use Mogami 2893.

I picked up a pair of these on Black Friday here in Canada for $69.99. I started by burning them in for about 72 hours on my pc system, driven by the headphone amp in my Asus Xonar Essence ST sound card. To start, they are light, comfortable, and are a nice compact size for an over ear headphone (although they might not fit over everyone's ears) So far I've listened to some jazz, rock, hip hop and alternative (mostly FLAC files) and I'm very impressed for the price! I've also listened to some music and youtube videos with them on my other devices and they definitely sound better in my computer rig than they do driven by my Galaxy SIII or Nexus 7 tablet. I will concede that neither of those devices have any problems driving them to reasonably loud levels.
 
The sound is fairly well balanced and neutral through the frequency spectrum. I'd say they're fairly transparent through the treble and midrange. They do get slightly muddy and just a bit recessed through the bass and sub-bass, but for the price it's very difficult to complain too much. For reference, in this system I also have a pair of M Audio BX8 D2 studio monitors, and they produce more lifelike and punchier bass. 
 
I've also owned a pair of AKG K27i on ear headphones and a pair of Shure SE102 earphones, but I think these HD360's are the best phones that I've had yet. I'm not sure how they fare at their regular selling price of $179.99 here in Canada, but I would guess they might fall short compared to the Audio Technica ATH-M50S which sell at the exact same price. Anyone care to comment on that?
 
For what I paid, I will happily be using these as excellent, cheap, travel companions!

In Canada, Futureshop is having them on sale for $69.99 at the moment.
 
I bought a pair but I am hesitate to open them because Futureshop has a strict no return policy due to hygenie reasons (in my opinion, its a stupid made up rule used to block people from returning the products).
 
Would love some update and further opinions on this.... thanks!

gilsont said:

  In Canada, Futureshop is having them on sale for $69.99 at the moment.
 
I bought a pair but I am hesitate to open them because Futureshop has a strict no return policy due to hygenie reasons (in my opinion, its a stupid made up rule used to block people from returning the products).
 
Would love some update and further opinions on this.... thanks!

Click to expand...

 
you are fine opening it
there's no such restriction on headphone returns

You CAN return them, even if they're opened. The return policy on their site is quite clear. - Headphones are specifically listed as one item that is returnable even if opened.
 
I also ordered a pair of these from Future Shop as a gift for someone.

overimagination said:

  You CAN return them, even if they're opened. The return policy on their site is quite clear. - Headphones are specifically listed as one item that is returnable even if opened.
 
I also ordered a pair of these from Future Shop as a gift for someone.
 
 

Click to expand...

 
It CLEARLY states "

Returnable within 30-Days of Purchase date – only if unopened*​

...Headphones..." 
http://www.futureshop.ca/en-CA/help/returns-and-exchanges-policy/hc82.aspx
 
[Moderator Edit: Please don't be rude.]

There is no asterisk next to where it says "Headphones."
 
To be super clear, below the table it even says "*Apparel, fashion apparel, linens and bedding must be unused, unworn (if applicable), unlaundered and still have the original tags attached. Furniture must be unassembled and still in the original packaging. Mattresses must be unsoiled, undamaged, and show no signs of use."
 
Apparel, fashion apparel, linens and bedding also happen to be the only ones marked with an asterisk in the table.
 
The point: You can return opened headphones

Ok, enough of the bickering guys, unless you'd like me to lock the topic.

HD360 is PX360 with a longer cable.

Well I finally have something to compare these to. Today I picked up a pair of Sennheiser Momentum Over-Ear phones (for $250!!), and upon first listen.. (I'm sure no one is surprised) it's apples and oranges. When I switch from the HD360Pro's to the Momentum, it's like a veil has been lifted. There is a little bit of a strange soundstage with the 360's where they don't seem to 'image' that well in between the two drivers. With the Momentum, they smoothly and seamlessly fill in the entire sonic picture.  They present music with a much wider and deeper soundstage. They also have better bass (more forward, punchier, tighter) and appear to have slightly more bass. The mids and treble are more resolved as well. They are very well balanced and easier to listen to. 
 
I'm very impressed with the Momentum! They're my first pair of real--deal headphones (although I have pretty respectable HT/2 channel systems and decent studio monitors in my computer system). I'm hoping that they open up even more with a few days of burn-in. Even if they don't, I'm still extremely happy with my decision to upgrade. I was lucky to get them brand new for a very good price from someone locally who needed some quick Christmas cash.
 
I still say that for $69, it's impossible to go wrong with the 360's.
 
I'll try to settle the dispute as well. I no longer need my 360's, so I'll try returning them to Future Shop (although they have had music playing through them for approx. 100hrs) and see what they say. If I can't return them, I'll keep them as a back up pair or give them to a friend for Christmas.

I also opened my 360s today and compared them to my AKG K550s and the AKGs are much better. Also sounded like a veil had been lifted.
 
But the 360s are nice and lightweight and comfy, and sound fine just not as good as the AKGs. And they're also half the price.

I just brought them home from Future Shop local store. I'm no professional at all but overall they sound pretty good. Tried em with flac audio files ( classical - opera - hiphop - metal ) and pretty impressed with the sound quality. The only other headphones I got were the one that came with my Galaxy S3 so my standard isn't really high ! I read a lot of reviews on this site, which is amazing by the way, and they all helped me figure which kind of headphones I wanted ( open, closed, OE, etc ). I used them for about an hour and can tell they are comfy and the weight is acceptable. Anyway I just wanted to add my .02 !
 
Thanks again to this superb forum ! I discovered a new passion for headphones ... I didn't know it was such a world of differences between different phones !
 
BTW sorry for my English I'm not that good but I'm pretty sure you understand what I'm writing !

hifiguy528 said:

HD360 is PX360 with a longer cable.

Click to expand...

I don't agree with you. The HD 360 uses Neodymium Drivers and the PX 360 uses DuoFol Drivers.
Should it be the same ? Or different drivers ?