Dolby Headphone is a virtual technique:
https://www.dolby.com/us/en/technologies/dolby-headphone.html
"The Dolby Headphone processor combines the 5.1-channel audio information into two encoded channels that deliver the spatial properties of the original audio. The result is natural sound that seems to extend far beyond the confines of the headphones."
The Dolby HRTF is applied somewhere in the sound path (in a home theater receiver, in an external sound processor that takes a multichannel digital input such as a Turtle Beach Earforce DSS, in a USB sound card for a gaming headset, in software in a PC etc.). Dolby Headphone can "expand" a stereo source so it sounds more like speakers in a room (applying an HRTF to it) or it can take a multi-channel audio source (5.1, 7.1, etc.) and apply an HRTF for that so that it sounds more like multiple speakers in a room, i.e. creating a proper sound field where you can localize sounds around you and it doesn't sound like it's all in your head (which is what headphones sound like when a recording is not binaural and when no HRTF is applied, because sounds are being playing exclusively to one ear or the other which would never happen in the real world).
If you look at the multi-driver headphones out there, they are not Dolby Headphone solutions. Let's look at three major ones:
Razer Tiamat 7.1v2
https://www.razerzone.com/gaming-audio/razer-tiamat-71-v2
Roccat Kave XTND 5.1 Digital
https://www.roccat.org/en-US/Products/Gaming-Sound/Kave-Series/Kave-XTD-5-1-Digital/
ASUS Strix 7.1
https://www.asus.com/us/Headphones-Headsets/STRIX_71/
The Razer Tiamat takes mutlichannel analog audio and that goes to a "control module" powered by USB which handles amplifying the analog signal to each of the drivers in the headphone, and it has analog passthrough for hooking up surround speakers. The Roccat Kave XTND Digital comes with a control module that is a USB sound card (so any sound card in the computer cannot be used with the Kave XTND, and the control module's speaker outputs are coming from the sound card in the module). There is also a Kave XTND Analog which doesn't have a large control module and instead takes in multiple analog sound channels from a sound card and is powered by USB. The ASUS Strix 7.1 acts as a USB sound card and (oddly) uses an HDMI connector port with a proprietary analog multi-channel break-out cable (giving the standard 3.5mm female mini jacks on the other end). It also has optional proprietary sound equalization schemes for specific genres (FPS gunfire mode, FPS footsteps mode, Action / RPG mode, Racing mode)
.
Speaking generally, there are a lot of issues that tend to be common to headphones with multiple drivers. They tend to be bigger, heavier, less comfortable, and not sound as good as headphones with single drivers in each cup. A well designed headphone will take a number of design measures to minimize things like reflections and vibrations that can cause ringing and unwanted distortions in the sound, and by cramming multiple drivers into cups the challenge for any headphone designer is greatly multiplied. And it has to be asked, what do multiple drivers crammed into earcups for surround sound accomplish exactly? Surround sound in a home theater accomplishes two things - it provides multiple discreet channels of sound delivered from specific physical locations in a room and re-routes different parts of the sound spectrum from the multiple channels to the most appropriate speakers (advanced forms of this are Audyssey MULTEQ XT32 and Trinnov Optimizer). A home theater receiver will at least know through the speaker setup what "size" speakers are (whether they are full range or not) so sound can be re-routed as necessary to the best speakers for playing back certain frequencies. We know that multi-driver headphones have different sized drivers, but this really seems unnecessary to me since it is possible to have a single driver that covers most of the full sound range well (unlike most full-size speakers in a room) and unlike in a room multiple drivers in a headphone are all next to each other, so what are they doing there besides making a headphone designer's life difficult? And they also don't create any sort of HRTF (i.e. there is no accounting for left channel sounds reaching your right ear and vice versa on the other side of your head with head equalization and timing without applying an HRTF even with multiple drivers, so it won't sound like natural surround sound simply being fed multiple surround channels of sound.
As far as Dolby Atmos on PCs goes, my only experience with it is with the game Overwatch, which has it built-in to the game under their headphone mode (independent of Windows). While I have PowerDVD on my HTPC, I haven't yet hooked up headphones directly to my HTPC and purchased the Atmos license and tried to use Atmos for headphones that way. I've heard different and sometimes contrasting anecdotes about Windows 10, Dolby Atmos, PowerDVD, Microsoft Movies & TV, and VLC Player. I can say that no FLAC or MP3 files of R.E.M.'s 25 Anniversary Deluxe Edition of Automatic for the People will be Atmos capable. Dolby Atmos can work as an extension to lossy (Dolby Digital Plus) or lossless (Dolby True HD) multichannel audio that places sounds in 3D space that includes height (elevation) which is why with a Dolby Atmos speaker setup you need to have either direct overhead mounted or bounced (front emitting angled driver reflected off ceiling) height channels. In the case of Blu-Rays with Atmos, you need to make sure you have ripped and preserve unaltered the Dolby TrueHD track with software such as MakeMKV, and then you have the hope of being able to play back the track (but again I'm not sure how easy it will be to get that rendered into a Dolby Headphone two-channel signal on a PC right now... maybe it will jsut work though with the right combination of software).
Most of my surround experience on headphones comes from Creative's CMSS-3D which works with DirectSound3D and OpenAL and legacy EAX titles via Creative ALchemy. I have my games set to 5.1 or 7.1 sound configuration and the Creative controls set to headphone and I get a very accurate spatial sound field that sounds very natural. Some games also use Blue Ripple Sound's APIs, which provides it's own control panel and the ability to select from a few different HRTFs. They also sell an advanced version which allows you to import your own personalized HRTF from an AES69 file. (Quick side note: unless you have a custom-made HRTF for your personal head and then use it with something like Rapture 3D Advanced, most HRTFs are generalized heads that won't exactly correspond 1:1 to your particular head, so listening even on the best headphones imaginable will not be exactly like speakers in a perfect room for you if the simulated head doesn't quite correspond to your own, but obviously they try to make the generalized simulated heads work well for most people.)
So in summary, I think you'll find that any good headphones (and from the Innerfidelity measurements page the Ultrasone Signature Pro are good headphones, unlike say the Ultrasone Edition 10 which you fortunately do not have) combined with a properly applied and quality HRTF being fed the best possible multi-channel signal is, I think, the way to go - not multiple drivers in a each earcup in a headphone.
