I started off with a rough $175 budget and explored the usual suspects- the Audio Technica M50x, Shure 840, Sennheiser Momentum, Sennheiser HD380, Sony MDR-1r, AKG 545, NAD HP50, even the V-MODA M100. At this point, I've auditioned all except the Sony and AKG. The M50x was too artificial in the treble and muddy in the bass, the 840 and HD380 lacked immersion and sub-bass extension, the HP50 sounded nice but had comfort issues, the M100 had great sub-bass but meh midrange and highs for the money, and the Momentum (which I just returned) was too laid-back, although they were my favorite out of the bunch and I enjoyed their constant smoothness and lack of fatigue.
/preface
 
So. Sensing that my sonic appetite exceeds that of my previous budget, I've decided to increase it to ~$400. This will be my first real quality headphones, and I'm looking for something special, something that I'll want to keep in my future collection no matter how big it grows from here.
 
Sonically, I like a smooth presentation with deep sub-bass that's engaging and musical. Neutral to warm tonality. Not overly bright. Resolving detail and expansive high-end extension but no sibilance or harshness. Not aggressive or too-forward. Real, immersive, controlled, and refined. Closed or open, doesn't matter. Doesn't "need" an amp.
 
I stay close to the JBL target curve in my car, something like
-20-60hz: +6db
-60-160hz: Transition to 0
160-3khz: Flat (0)
3khz+: Gradual Roll-off to -6db @ 20khz
 
Obviously headphones are different and I'm willing to compromise. I anticipate that the headphones I'm looking at will not have the sub-bass attenuation that I consider ideal. The M100 almost had it, but the sub-bass alone couldn't make up for its other inadequacies as a whole. I want something that I'll put on and want to keep on for hours.
 
Priorities [Music -> Movies -> Games] Sources [mostly laptop, sometimes Onkyo TX-SR707, rarely iPod Classic] Genres [electronica, electronic soul, indietronica, downtempo, deep house, synthwave, nu-disco, synthpop]
 

1. HiFiMaN HE-400 – Excellent sub-bass, but maybe a touch too bright/sibilant on the lower treble?
2. Master & Dynamic MH40 – Looks beautiful, but is it worth the money, sonically?
3. Bowers & Wilkins P7 – Not my favorite look-wise.
4. Sennheiser Momentum 2.0 – Despite reports of revolutionary improvements over the first version, I'm still hesitant.
5. HiFiMan HE-400i – I like what people say about them, but they're expensive and could use a tad more sub-bass extension maybe?
6. Philips X2 – Excellent reviews everywhere, just a few reports of dye-leaking issues and that the suspension mechanism loosens over time requiring occasional repositioning.
7. Oppo PM-3 – Perfect?

 
I'm leaning towards the PM-3. Which of these should I stop considering? Did I leave any obvious ones out?

I just picked up a pair of the Momentum M2, they seem to have a bit better detail compared to the M1, and they fit much better.  
 
Another similar sounding headphone (going by frequency response) is the Focal Spirit Classic.  It has that similar slightly warm sound, and has some excellent reviews.
 
PM-3 definitely seems like a good choice, I'd like to hear it.

Do you have a good DAC/Amp combo?
Sennheiser HD650 might be fitting then as well.
I would try if you could at least audition the Philips, Sennheiser and B&W. Opinions on the internet are nice and all, but once you have heard the real thing it should be easier for you to decide and easier for us to recommend things based on your experiences.

wolfjeanne said:

Do you have a good DAC/Amp combo?

Click to expand...

+1

This could affect which headphones would be a good choice for you. What's the make/model of the equipment you will be using your headphones with?

And also, are open headphones a good choice for you? Open headphones provide no isolation from the environment and leak sound. However, they have a bigger (most people would say better) soundstage than closed headphones.

Finally, I don't think I've ever seen any headphones with the bass +6db in the 20-60hz and then transitioning to neutral up from there. Any bass emphasis is generally centered much higher.

transmaniacon said:

  I just picked up a pair of the Momentum M2, they seem to have a bit better detail compared to the M1, and they fit much better.  
 
Another similar sounding headphone (going by frequency response) is the Focal Spirit Classic.  It has that similar slightly warm sound, and has some excellent reviews.
 
PM-3 definitely seems like a good choice, I'd like to hear it.

Click to expand...

 
I'll look into those again. The only thing that has swayed me from considering them in the past was reports of durability issues and ear cup size.

wolfjeanne said:

  Do you have a good DAC/Amp combo?
Sennheiser HD650 might be fitting then as well.
I would try if you could at least audition the Philips, Sennheiser and B&W. Opinions on the internet are nice and all, but once you have heard the real thing it should be easier for you to decide and easier for us to recommend things based on your experiences.

Click to expand...

 
No separate DAC/Amp at this time, that's why I don't want headphones that "need" an amp like the 650. I see myself getting a DAC/Amp combo in maybe 9 months, but my budget will likely be $150 for that. In the meantime though, I'd like it to be sensitive and low impedance enough to keep me happy without one.
 
AFAIK, the only place that sells the X2 new is Amazon. I'm not opposed to buying multiples and returning, but I don't want to do it too many times. The only headphones store I have here is Guitar Center, but I don't think they carry any of these. We have 2 Best Buy's, but they aren't the Magnolia versions.

cel4145 said:

+1

This could affect which headphones would be a good choice for you. What's the make/model of the equipment you will be using your headphones with?

And also, are open headphones a good choice for you? Open headphones provide no isolation from the environment and leak sound. However, they have a bigger (most people would say better) soundstage than closed headphones.

Finally, I don't think I've ever seen any headphones with the bass +6db in the 20-60hz and then transitioning to neutral up from there. Any bass emphasis is generally centered much higher.

Click to expand...

 
A Lenovo B570 laptop most of the time, and sometimes an Onkyo TX-SR707 (which I've heard has a headphone amp, but can't find specs). Rarely an iPod Classic 160GB. Opened or closed, either would work for my purposes.
 
Yeah, seems like they all have mid/upper bass emphasis. I don't mind EQ'ing, but I'd like them to have a good starting sound.

dryhopped said:

A Lenovo B570 laptop most of the time, and sometimes an Onkyo TX-SR707 (which I've heard has a headphone amp, but can't find specs). Rarely an iPod Classic 160GB. Opened or closed, either would work for my purposes.

Click to expand...

Yeah. AVR manufacturers are terrible about providing headphone amp specs, and so often it seems that their headphone amps are an after thought.

Given your equipment, the HE-400s are probably not a good choice. They are a bit difficult to drive because of low sensitivity and often don't work great with computers and portable devices unless you listen at very moderate volumes. They are also 35 ohm, and AVRs are often not good at powering lower impedance headphones.

cel4145 said:

Yeah. AVR manufacturers are terrible about providing headphone amp specs, and so often it seems that their headphone amps are an after thought.

Given your equipment, the HE-400s are probably not a good choice. They are a bit difficult to drive because of low sensitivity and often don't work great with computers and portable devices unless you listen at very moderate volumes. They are also 35 ohm, and AVRs are often not good at powering lower impedance headphones.

Click to expand...

Everyone talks about their lower treble spike too. I love the price though
 
I wish the HE-400i weren't so much more. Seems like they are much more polished and refined compared to the HE-400. I'm a big fan of the HiFiMAN look too.
 
I seem to be leaning towards the PM-3. I've never heard planar magnetics, so that's also exciting.

dryhopped said:

I seem to be leaning towards the PM-3. I've never heard planar magnetics, so that's also exciting.

Click to expand...

The official Oppo Store has a 30 day return policy. So not much risk in giving them a shot

cel4145 said:

The official Oppo Store has a 30 day return policy. So not much risk in giving them a shot

Click to expand...

Very true.
 
I wasn't considering it until wolfjeanne brought it up, but the HD650 was just on sale for $290 on Amazon, and I'm sure it will be again. That's cheap enough to where I could afford an amp to go along with it right now, but it would have to be a ~$120 amp, and I'm not sure I could find a new one for that price that would do the HD650 justice. More research needed...

HD600s have been $240 lately (check slickdeals for the link).

I think I would swap my HE-400 consideration for the AKG K712 Pro, which seems to have a lot in common, but is overall smoother and less rough sounding than the HE-400.
 
I'll have to revisit the HD650 vs HD600 comparisons. For some reason, I remember coming out with a more favorable view of the HD650.
 
I still think my front runners are (in order) PM-3, X2, Momentum 2, P7. The 400i I feel is just too expensive, and I'd rather try the PM-3 before that. Not sure where the K712 Pro or HD600/HD650 would fit in. Hopefully I'll have a clearer idea by tonight.

OK, going to order the Oppo PM-3 and Philips X2. One open, one closed... and I'll keep whichever I love more. It is happening. I just really hope the X2 doesn't leak dye on me, lol.

Most planars have very linear bass.

Quick update.
 
Just opened my Philips X2 that was delivered yesterday. I've listened to 5 songs total- my usual go-to songs for auditioning speakers.
 
First impressions: Leagues better than anything I've heard so far. Smooth, dynamic, and detailed. And finally, sub-bass! It's not as boomy as some of the phones I've listened to like the Momentum or M50x, but it extends DEEP and it's textured and very articulate. Reminds me of the M100, but cleaner. Will be playing as much music on them as possible over the next few days.
 
So happy so far, and I still have the Oppo PM-3 on the way to audition as well!

Great! Can't wait to hear your comparison.