My concern is that increasing the price moves you into range of some excellent headphones, but many of them will need an amp on the ipod. For example, if you liked the Momentum, then I suspect you would also like the Mr. Speakers Mad Dogs, but they definitely need an amp, and the are quite large and heavy.

Two more $300 headphones that I have not heard (but I want to) are the NAD Viso HP50 and the PSB M4U-1

billybob_jcv said:

My concern is that increasing the price moves you into range of some excellent headphones, but many of them will need an amp on the ipod. For example, if you liked the Momentum, then I suspect you would also like the Mr. Speakers Mad Dogs, but they definitely need an amp, and the are quite large and heavy.

Two more $300 headphones that I have not heard (but I want to) are the NAD Viso HP50 and the PSB M4U-1

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Yeah that is one of the reasons I wanted to keep cost down.  Both of those look like good options, and were designed by the same guy IIRC, but I just can't get over the appearance of the NADs.  I have also read the build quality isn't as good as say the Momentums. 
 
I am debating just biting the bullet and getting the new Momentum 2s, they increased the cup size, improved the padding, made them foldable, and keep the same sound as the original Momentums.
 
I have also seen the Soundmagic HP150 recommended for a neutral headphone, but don't have the option to hear them first.

transmaniacon said:

I have also seen the Soundmagic HP150 recommended for a neutral headphone, but don't have the option to hear them first.

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I think they are a natural upgrade to the MDR-7506 for someone that likes those. Better sub bass extension than the 7506, and more refined sound.

cel4145 said:

I think they are a natural upgrade to the MDR-7506 for someone that likes those. Better sub bass extension than the 7506, and more refined sound.

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They are tempting, the price is great, but they seem more neutral and don't have that warmer mid-range of the Momentums.
 
I was also recommended the ATH-900x on Reddit, but I was under the impression most of the AT headphones have a V shape which I am not looking for.
 
I am almost settled on the new Momentum M2s, the sound is even better than the M1s, and they fixed the cup issue.

transmaniacon said:

They are tempting, the price is great, but they seem more neutral and don't have that warmer mid-range of the Momentums.

I was also recommended the ATH-900x on Reddit, but I was under the impression most of the AT headphones have a V shape which I am not looking for.

I am almost settled on the new Momentum M2s, the sound is even better than the M1s, and they fixed the cup issue.

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Definitely not what I would describe as warm. More similar to 7506 in overall frequency response character.

billybob_jcv said:

My concern is that increasing the price moves you into range of some excellent headphones, but many of them will need an amp on the ipod. For example, if you liked the Momentum, then I suspect you would also like the Mr. Speakers Mad Dogs, but they definitely need an amp, and the are quite large and heavy.

Two more $300 headphones that I have not heard (but I want to) are the NAD Viso HP50 and the PSB M4U-1

Click to expand...

 
Just out of curiosity, what kind of amp would you recommend for the MrSpeakers Mad Dogs?  I've read they will work fine through an iPod, but to get the most out of them you need an amp.
 
Seems like an incredibly comfortable, warm sounding headphone, and if I am considering the Sennheiser M2s, these are right up there like you said.

A Schiit Magni 2 should easily drive the Mad Dogs. Hard to beat for $100. Plus, then you can say you have some audio Schiit.

If you want a portable amp, the FiiO E12 and Cayin C5 have the reputation for the most amount of power. I have the E12 and use them with my HE-400s (supposedly similarly difficult to drive) and it does quite well. Of course, the desktop amp is even better if you decide you want to crank things up.

So I went and listened to the Momentum M2s at Best Buy and they fit very well, grabbed the last pair there and am enjoying them right now!  I've got 14 days to decide if I want to keep them, but they sound excellent and the updated version makes them actually over-ear; very comfortable.