What Is the Main Difference in Sound as You Go Up in Impedance Compared with 300Ω?
George DeMirjian: What is the main difference in sound as you go up in impedance compared with the 300Ω? Thanks.
John Massaria: The biggest difference is smoothness and refinement.
Compared with the 300Ω version, the higher-impedance models have a progressively smoother, more relaxed, and more refined presentation. As William Murdock has mentioned, the 300Ω can sound a little more airy because it has somewhat more upper-frequency energy and peaks. He actually prefers that presentation, which is perfectly understandable because he enjoys the additional high-frequency presence.
The 540Ω, 740Ω, and 980Ω versions take the presentation in a different direction. They have an exceptionally smooth overall response, with far less emphasis on treble peaks or edge. The higher you go in impedance, the more effortless and silky the presentation becomes.
That doesn't mean the 300Ω is harsh—it isn't. In fact, all of the XTC2 versions, including the 32Ω, 64Ω, and 300Ω, are designed to be smoother than many extremely detailed headphones on the market. The difference is that as you move upward in impedance, the presentation becomes increasingly natural and refined, while retaining all of the information and detail.
That's one of the things I find so interesting about these headphones: you don't give up detail when you move to the higher impedances. On first listen, the 540Ω, 740Ω, and 980Ω may seem slightly less airy than the 300Ω, but spend some time with them and you realize that the information is still there. It's simply presented without the peaks or edge that can make some headphones sound more aggressive or hyper-detailed.
The 300Ω XTC2 Universe winning Headphone of the Year this year is a good example. It is an exceptional headphone in its own right, and some listeners will actually prefer its slightly more energetic presentation.
At 540Ω and above, however, I believe you're entering the summit tier of what a dynamic-driver headphone can produce. The 980Ω is the smoothest model I offer, although the difference between the 540Ω, 740Ω, and 980Ω is relatively subtle. The 980Ω is simply a little more effortless and silky, while also being somewhat more demanding of the amplifier.
The 740Ω and 980Ω also pair exceptionally well with the Aune BX2. In fact, the BX2 with the 980Ω is sublime. There is something genuinely special about that combination to my ears.
The Cobalt models follow the same general philosophy but are easier to drive. The 80Ω Cobalt is one of my personal favorites. If you feel your amplifier is better suited to a lower-impedance headphone, I would seriously consider the 80Ω Cobalt rather than going all the way up to 540Ω.
I hope that explains the differences, but you're always welcome to email me if you want to go deeper into the differences between the individual impedance versions.
Michael Slattery: John, I have the same question as George. Why would we want a headphone with such high impedance, and doesn't that limit our choice of amplifiers?
Ty Powell: The higher impedance seems to really smooth out the treble. I had the 64Ω Burl Woods and eventually moved to the 536Ω Burl Woods, and the difference in treble smoothness was night and day.
The bass hits hard with both, but to my ears the higher-impedance version has an especially controlled and authoritative character.
My Aune A17 is only on gain 2 of 4 and has more than enough power to drive them effortlessly. My Cayin HA-6A on high-impedance mode doesn't even break a sweat.
I was initially concerned because they're over 500Ω, but there's really no reason to worry if you're on the fence. Even a relatively modest desktop setup, such as the Aune S17 Pro, handles them without a problem. They're surprisingly easy to drive to whatever volume you want.
I haven't used my Utopia, Empyrean 2, HE1000SE, or Stellia in several weeks. They're that good. I'm actually listening to them right now.
Michael Slattery: Ty, the amplifiers aren't really the concern for me. I currently have four headphone systems: an Aune A17, Benchmark HPA4 with an AHB2, Cayin HA-6A MK2, and a Ferrum Hypsos/OOR with a Wandla GSE DAC. I also have a custom Zynsonix converter box for using my stereo speaker amplifiers.
Most of my headphones are lower impedance, including the Audeze LCD-5, Abyss Diana DZ, Hifiman Susvara OG, Grado 325x, RS-2X and S950, Meze Empyrean and Elite, and ZMF Caldera Open.
The higher-impedance headphones I currently own include the Sennheiser HD800S, HD580, and HD650, along with a few others.
John Massaria: Precisely, Ty. I wish you could share that exact sentiment in the owners' thread!
The Cobalts offer that same smooth character but are even easier to drive at 80Ω. The 540Ω is essentially neck-and-neck with the 740Ω and 980Ω, with the presentation becoming just slightly smoother as you continue moving upward in impedance.
Personally, I believe the 540Ω is one of the best headphones anyone can buy from any manufacturer—even at twice the price or more.
I'm actually rocking out with the BX2 with BP1 right now as I type this, and this combination continues to amaze me. Everything is exactly where it should be. There is a level of control, separation, smoothness, and musicality that makes you stop thinking about the equipment and simply listen to the music.
For reference, I'm using the Aune BX2 with the BP1 ($999) and a Gustard X30 ($2,699 on our site, delivered with all taxes included). The BX2 sounds sublime in both tube and solid-state modes, although with this particular combination, I personally prefer the tube mode.
It really has that “set it and forget it—stop shopping, you've arrived” quality. This is summit-level performance.
I know it may seem unusual to pair a $999 amplifier with a $2,699 DAC, but honestly, even if you fed the BX2 with something as serious as a Denafrips Terminator 15th, I still believe the amplifier is worthy of it.
The BX2 is that good. Feed it the best source you can, and it will let you hear everything. You won't miss a note, a nuance, or a detail.
