An interesting happened while Dan Clark of MrSpeakers was developing his upcoming electrostatic ETHER--he came up with an idea to make a better planar magnetic ETHER. While it is thought by many that the ultra-low-mass nature of the traceless electrostatic driver is what gives it its key advantages over its planar magnetic counterpart, Dan and his team came to an additional conclusion, and a resultant theory. Listening to his electrostatic ETHER prototypes, Dan and his team felt that a lower-mass diaphragm couldn't fully account for the electrostatic performance advantages they were hearing--that there had to be other advantages with electrostatic driver assemblies. (Above) MrSpeakers ETHER Flow with included DUM Cable What they eventually determined was that one very significant advantage that electrostatic drivers have, versus planar magnetic ones, was air flow. Though both planar magnetic and electrostatic motor assemblies use planar diaphragms, electrostatic drivers do not use magnets at all. The only things, then, between an electrostatic's planar diaphragm and air on either side of it are typically very thin, flat, perforated stators. Planar magnetic headphones (as the name suggests) do require magnets on at least one side of the diaphragm (sometimes both sides, depending on the design). The magnets used are typically bar magnets or magnets in trays that in either case are far thicker than an electrostat's stators, and that present a slew of thick- and flat-walled channels and right-angles for air to move past and around. What Dan and his team determined was that the diffraction and reflection of air as it moved around these magnet assemblies was a likely cause of distortion and lost resolution (especially low-level detail), so they set out to fix that. They aimed to make the their planar magnetic motor structure look more like an electrostat's stators to the audio waveform passing through it. To accomplish this, the team at MrSpeakers developed waveguides to sculpt and smooth not just the areas immediately outside the magnets (something that others have also worked on), but also to sculpt and smooth the spaces between them, on both sides of the diaphragm. What MrSpeakers developed they're calling TrueFlow. To help you understand it, here are some illustrations showing magnet structures without TrueFlow, and then (in color) those same components with TrueFlow waveguides--it'll make more sense after you look at these: (Below) This is a cross-section view of a magnet in the tray without TrueFlow (left) and with TrueFlow (right). Notice that TrueFlow waveguides are added on the other side of the tray (again, to minimize right angles): Here's an animated simulation showing the movement of air between magnets without TrueFlow installed: (Below) In these animated illustrations, the movement of air through the driver structure is shown, first without the TrueFlow waveguides (top) and then with TrueFlow (bottom): So, after all this, does it work? While it all seems to make perfect sense to me, I have to admit that I'm not qualified to answer the question. What I do have is a pair of my own ears, as well as a pair of artificial ears on a G.R.A.S. hearing simulator hooked up to an Audio Precision APx555 audio analyzer. Let's start with what I hear with my own ears from the new MrSpeakers ETHER Flow versus the standard ETHER. What I hear with the ETHER Flow is a substantial improvement in low-level detail retrieval versus the standard, non-Flow ETHER. While I cannot say TrueFlow brings the ETHER planar magnetic platform to the level of effortless sonic scanning electron microscopy that the Stax SR-009 is capable of, it does bring the ETHER Flow into the top tier of the non-electrostatic world in this regard--that I can say very comfortably. Also, the ETHER Flow brings greater dynamism and presence to the bass (versus my first-generation ETHER)--something I expected would be easily visible in the frequency response measurements (which we'll get to in a minute), but wasn't. I asked Dan about this, and he said it was part of a new tuning, and also that perhaps reduced turbulence due to TrueFlow results in less back pressure, which could improve dynamics. The ETHER Flow's bass sounds more impactful, as well as faster, whatever the reasons. In terms of measurements, if TrueFlow was supposed to result in lower distortion, then mission accomplished. Look at the THD measurement for the new ETHER Flow (below, click to see larger version). Here's the ETHER Flow's frequency response plot: NOTE: The measurements reflect diffuse field correction applied via the APx555's input EQ. Audio measurements were made using: Audio Precision APx555 audio analyzer G.R.A.S. 45CA Headphone/Hearing-protector Test Fixture G.R.A.S. KB0072/KB0073 small pinnae; G.R.A.S. RA0045 IEC 60318-4 ear simulators including G.R.A.S. 40AG microphones; G.R.A.S. 26AS 1/4" microphone preamplifier; G.R.A.S. 12AP microphone power module Rupert Neve Designs RNHP headphone amplifier Herzan acoustic enclosure (custom) Simply put, the ETHER Flow possesses a certain effortlessness with how it goes about its business--it heaps resolution at you, but never punishes you with it. It has slam, but never overcooks it past reference levels. Will I be updating my ETHER to Flow? I'd be silly not to, and am thankful there's expected to be a reasonably priced upgrade path for current ETHER owners like me (more on that below). With the performance gains MrSpeakers has given its planar magnetic ETHER platform withTrueFlow, their upcoming electrostatic ETHER has its work cut out for it. The ETHER Flow brings extraordinary clarity while still being impactful and smooth. I think it's a really neat story that improvements in MrSpeaker's planar magnetic technology came from their work on their upcoming electrostatic headphone. NOTE: The ETHER C Flow (the closed-back version) arrived just before the time of this writing, so I'll give the ETHER C Flow more listening time before I say much more about it. What I will say now is that my first impression is that MrSpeakers' TrueFlow waveguides have made what was already one of my favorite closed-back headphones better. As for availability: ETHER Flow and ETHER C Flow will be demonstrated on Thursday evening July 14, 2016 at Audiovision San Francisco, and on Saturday, July 15, 2016, at the San Francisco Head-Fi meet. ETHER Flow and ETHER C Flow come with MrSpeakers' hand-made DUM (Distinctly Un-Magical) Cables, and are available for immediate purchase at https://mrspeakers.com/ for $1,799.99. Shipments will begin in volume within four weeks. Effectively immediately, ETHER and ETHER C Headphones with a DUM Cable are now $1499.99, and the standard cable option is no longer available. Upgrades to ETHER Flow and ETHER C Flow will be available for existing owners in the near future; upgrade price is to be determined.