do you think an iFi Zen Air DAC or used Zen DAC and an HE-400se is a good start?
they have the Sony XM4 headphones and KRK Rokit 5, dunno what gen, powered by a Behringer PA amp.
their music taste is quite ecclectic and I think they lean on the warm side like I do as much of their music is ambient electronica.
thoughts?
I came to say planar, as I’ve noticed some shock and awe from that experience. HE-400SE/HE-X4 is a good way to get that taste for so little.
I do always get nervous with anyone coming into “hifi” about a lack of bass, as that is one element of consumer-level gear that is pronounced. Others disagree, but I do think that even this level of planar does well to dig at the ultra-low frequencies of electronic bass relatively well and of course can take to EQ.
The HE-400se is a fine choice for an entry-level planar-magnetic headphone.
But you’ll need more than just a DAC. Planars demand power, so you’ll need an amp. You could either go with a solid portable solution such as the iFi hip-dac 2 ($179 USD) or a desktop DAC-amp “stack,” which will give you more and cleaner power but no portability. The JDS Labs Atom+ DAC and amp can be purchased together for about $210 USD. I have used both the hip-dac and JDS Atom+ stack with the HE-400se.
One word of advice: Don’t expect bass like your Sony XM4’s from audiophile headphones. Consumer sound signatures like those used by Sony for its wireless over-ear cans are V-shaped – very bass- and treble-heavy, with little to no mids. That’s not audiophile.
The HE-400se will deliver solid bass. But it will sound light compared to your XM4’s, without question. If you’re a true basshead, there are audiophile cans that will lay on the bass but keep it from bleeding and booming into the mids like your XM4’s.
Good luck!
both the Zen Dac and HE400se are stellar entry level items as long as the comfort doesn’t bother them
they have a decent sony. i think something like the koss starter pack, for the variety of sounds on the cheap, might be a better and more practical way. the he-400 is more of a sidegrade to the sony’s. YMMV
well, I went with the new iFi Zen Air DAC and the HE-400se.
well boo. they got the gear and he headphones are DoA out of box…one ear no workie. 
ordered them off Amazon, so sending them back and will buy another pair. 
They’ve been simultaneously introduced to the legendary HFM build-quality! lol
I say in jest as someone who has only had solid experiences.
same, I’ve not had any issues with any of my HFM and I’ve had 3 pairs go through my hands.