First Impressions of DTS Headphone:X

The Hardest Thing to do on Headphones
Mother Nature has given us ears exquisitely designed to make your head turn to face exactly where that twig snap was heard. When our eyes and thoughtfulness are narrowly focussed, our ears are wide open and capable of establishing a spherical awareness of our surroundings aurally...with nary a thought. It works damn good, and fooling it is no easy task.

I've heard a whole lot of headphone imaging schemes: simple cross-feeds from HeadRoom and Meier; digital headphone amp units like the Sennheiser Lucas, AKG Hearo999, Beyerdynamic Headzone; wireless headphones with Dolby Headphone and various SRS implementations; and one-off attempts like that in the sweet, but now long-discontinued, Sony D-555 portable CD player, and many in various portable DVD players. With one singular exception, they've been convincingly unconvincing—they never really get the sound out of my head. The one exception is the Smyth Realizer; a piece of gear that requires you to have your ears measured in a reference surround system and room, and which includes the ability to track your head movements. It's complicated and expensive, but it works, and it works mostly because it measures your ear's response to a particular model of headphones, and your ear's response to real speakers in a room. It's got your Head Related Transfer Function (HRTF) down pat...and it creates changing HRTF cues with your head movements.

Monitoring head movement is incredibly important for out-of-head localization. You brain can hear the various acoustic cues developed by reflections and time differences in and between your ears, but what it's best at hearing is how those cues change when you move your head. When people search for sound sources in a dark room, they gently wiggle their head back and forth about +/- 3-5 degrees to hear the way the cues change as they hunt for the sound source. When you can't move your head relative to the source of the sound, localization acuity drops dramatically. It's like staring at one thing for a long time, eventually you can't see what your looking at any more unless you move your gaze.

Making you believe you're hearing speakers outside your head when wearing headphones is incredibly hard. You need to account for the direction of the source of the sound; the sound of an acoustic environment (the room); reflections off the pinna (outer ear)—which is somewhat individual; the acoustic corrections needed for the headphones; and, if you can, how all these signals change with head movement. It's a daunting computational task.

Enter Headphone:X
Daunting computational tasks are something with which DTS is intimately familiar. DTS (Digital Theater Systems) is all about recording, transporting, and decoding multi-channel audio. They have a bevy of codecs and audio processing software for equipment used in everything from recording studios and sound stages, to consumer equipment in home theater systems, TVs, sound bars, computers, automobiles, and mobile devices. With Headphone:X, they're adding a systen for reproducing multi-channel audio on headphones.

My first thought when I heard of the projects was, "Good luck with that."

Like I said, I've heard most of what's been available, and to set out to make a generic version of surround for headphones on tablets and smart-phones is close to a fools errand. But here's the thing: if you can pull it off, you'll rule the world...of headphones, anyway. So, it was with great interest that I took the opportunity to visit DTS's Calabasas, CA facility to get a personal demo of Headphone:X and chat with some of their product management and engineering team.

Flip the page for my impressions.

DTS Inc.
5220 Las Virgenes Road
Calabasas, CA 91302

Impulse's picture

I guess mobile devices would indeed be biggest market for this kind of virtualization right now, since those are the devices and scenarios in which masses tend to use headphones the most... But frankly I've got very little interest in watching a lot of movies on small screens (maybe if I traveled more), and mobile games definitely won't benefit much.

I want this kinda thing on my HT receiver (where stuff like Dolby Headphone has gotten marginalized), or on my PC (tho we already have other competing technologies there, including DH and Creative's ever changing portfolio).

I'm surprised DTS or Dolby or one of these other companies hasn't aligned w/Sony or Microsoft to incorporate something like this on one of the next gen game consoles (maybe they have and it just hasn't been announced?). Game consoels are just as large of an untapped market as the mobile space IMO, and the clincher is that they already have advanced head tracking devices available!

Seriosuly, that kinda tracking should be easy for something like the Xbox's Kinect, and they can leverage it for movies played on the consoles and make them the ultimate movie players (Sony/MS are already trying to make them entertaiment centers anyway).

I'm not even a console gamer anymore but I think the combination would be fantastic, I mean, gamers are some of the most common users of headphones to begin with... Thus far the console market has been solely served by DH devices like the Astro Mixamp and TB DSS, fairly limited/kludgy solutions compared even to the PC space...

Tyll Hertsens's picture

....while DTS's strongest focus for this product is mobile, I'm sure they intend to roll out this product on many platforms. It's not exclusively for mobile, that's just the main focus. And I agree, it could be a rocking good time for gamers.

Cami's picture

why would I watch a good movie on a tiny screen? I've been using my Macmini connected to my TV via HDMI for at least three years now, and I got rid of CD/DVD/BluRay player. I use an optical drive to rip my media, store it all on an external drive and that's it. The mini is hooked to a DAC via USB, that is hooked to a pair of active speakers, end of story.
The thing missing here is a Z + Music App for my mini, since I rarely get the opportunity to watch a movie on a tablet or laptop, unless I'm forced to do so, by sitting several hours on a plane.
The Demo works fine with HD800s, K702s and HFI-2400s, with a slight difference from one headphone setting to the other. The soundtrack material is quite truly useless, and I have heard many more convincing - and less compressed - soundtracks without Z +. I would also rather hear a complex action scene with dialogues, instead of the soundtrack. 
I think there's a lot of people using their macmini as their media hub in the living room, or that at least use a 27" iMac to watch movies on. As silly as it may sound to some, putting on a pair of cans to watch a movie if you've got speakers, there are plenty of situations that make it a good solutiuon, including the one where you really want to enjoy every detail, and when you only have a stereo setup and don't wanna ruin your living room - and your wallet - with a bunch of speakers and cables.
I found the demo quite OK and just as convincing as David Chesky's binaural demos over headphones. But I wouldn't lose my time watching movies on an iPod or iPad. Let's hope they figure this out soon.


Argyris's picture

EDIT: Nevermind. I kind of answered my own questions, and instead of arguing with myself, I'll bring up another point.

I wonder what kind of companies will be interested in getting certified, and which parts (if any) of their lineup they'll put forward. This technology might be good, but it's also the kind of thing that usually gets a slick marketing-friendly badge that gets slapped on consumer-level equipment. Will the likes of Sennheiser and AKG and Beyer get their flagships certified? Or will we see a rash of cheap mass market cans with MegaXXXXXXXXXXXtraBassXtreeeemePlus have this badge put on there? In other words, is this technology something higher end users are going to care about, or is it just going to be something for the mass market consumer? It'll be interesting to see different companies' takes on this.

Tyll Hertsens's picture

....DTS will look at the technical performance of the cans and dertermine that many simply aren't able to work well when compensated.  Most likely they'll contact the major players in various segments to have their phones qualified.

For example, I stumbled across this post from Scott Wilkinson announcing Turtle Beach as having the first Headphone:X ready headphone. They're a gaming headset player.

John Grandberg's picture

Looks like a fun little field trip, Tyll. I wonder what speakers those are? I want that setup in my house.

This is a fairly ambitious project - there are so many ways to do it wrong. And doing it perfectly doesn't necessarily translate to a more profitable venture. Argyris makes a great point above.... is this something headphone manufacturers and enthusiasts will take seriously? Or simply another badge to add to the marketing fluff? 

My experience with the heaDSPeaker setup shows me that it can in fact be done, in a generally effective way. But without head tracking, it's an uphill battle, and even then some headphones work better than others. And yes, ergonomically speaking, the head tracker is difficult to integrate. 

Still, I'd love to see this succeed to a reasonable degree. Even if it merely ends up being good and not amazing, that's better than most current options. 

Tyll Hertsens's picture

I think they were Focal speakers, and for a mear gajillion bux I'm sure you can have one installed in your home. :)

I think their focus on "exhaustive, not innovative" will get them to very good. Amazing, I reckon, is only achievable with custom measurements of each users ears. And yes, that will be a lot better than down-mixed surround for stereo speakers on headphones.

veggieboy2001's picture

I don't know if I'm missing something, but from what I gather, the effect seems pretty headphone dependent. Would a generic be feasible? I guess they could have a different app for each headphone? If so, how to determine which (discontinued etc).Or a small processor with downloadable codecs? I guess availability would depend on demand (which is impacted by availability...). a fascinating article, though...Thanks again Tyll!!

Tyll Hertsens's picture

My understanding is that they will measure headphones and the app does have the needed code to take into account headphone filters for particular cans.  Right now, the app askes only if you are using in-ear, on-ear, or over-ear headphones, but in future there will be a dropdown list of all qualified headphones so that you can pick the ones you have.

ultrabike's picture

I think DTS is making a move in the right direction with Headphone X. It is also farily encouraging to see a company such as DTS putting resorces into improving the quality of audio through headphones.

I think that the introduction of tablets and highly portable yet powerful computers are making some of these advancements possible and practical. While this may become available first in the portable consumer electronic devices, I have no doubt that if successfull they will be made available in receivers and several other consumer electronic products.

Regarding facial recognizion, while it's an area of currently active research, it is indeed a little complicated from what I know. However, I can see that succeeding at some point in time.

I will be keeping an eye on Turtle Beach DTS X implementation. Thanks Tyll!!!


RPGWiZaRD's picture

I've always liked "out-of-the-head" listening experience personally. So much I started some time ago finding out what one could do with already existing plugins/apps etc in order to give you such experiences. Most of the things I found severely degraded sound quality but with Dolby Headphone I thought this sounds still reasonably good if I would do some counter-EQing.

That's when I started tweaking foobar2000 using Dolby Headphone wrapper together with channel mixer (for HRTF tweaking and upmixing stereo into virtual 5.1 and Dolby Headphone is a 5.1 processed signal into stereo so channel mixer allows me to tweak how those "virtual 5.1" cues will work and the end result is then different too). Since Dolby Headphone also changes the frequency response a bit I started counter-EQing with Electric-Q (I preferred picking the best free options out there and in my ears Electri-Q does the best job for a freely available EQ). 

I've tweaked this config for maybe 1½ years or so, doing small small adjustments here and there eventually leading to near perfect result (at least how I hear it, ofc we all got different shape of ears and taste how it should sound like why I offer 2 different configs "forward" and "laid-back" of which I personally concider "forward" one better as I spent more time with it as I find freesurround plugin used with "laid-back" config can introduce some artifacts in some cases) but I've gotten very good response on head-fi forums in the thread.

(I haven't updated to latest foobar2000 because I'm both lazy & busy at the same time these days mastering hardstyle music tracks for newcomers on a pretty daily basis). I'm a person that's very experienced when it comes to interpreting what I'm hearing and making changes thereafter. I'm not blindly tweaking, I know exactly what I'm doing. :) 

sgrossklass's picture

Good new virtualizers are always welcome. I'll keep an ear out for this one - once I get some sort of smartphone or tablet, that is.

Personally, the only such thing I regularly use is Rockbox' "Meier" Crossfeed. It only removes the annoying one-ear-only sensations but keeps everything else intact, with no muddying of sound or anything like that. (So you get all the pros and less of the cons of headphone playback.) I have, unfortunately, been unable to find an exact equivalent for PC-based playback. One for Foobar would be neat. While RB is open source, it's completely integer based, so porting the code to float wouldn't be that trivial I guess.

DH always had too much "room" in the equation for my taste.

JRAudio's picture

I own a Meier Audio headphone amp and the "Meier Crossfeed" is already included in hardware, as it is also in the Grace Design headphone amp. This is "only" two channel playback, but it gives me a natural sound and I do not get as "tired" compared to non crossfeed designs, because this crossfeed makes the regular stereo mixes more compatible with the bi-aural listening, what headphone listening is.


markus's picture

Isone Pro is a free VST-Plugin, you can use it with f2k. The HRTF can be adjusted by ear size und head size, check the manual how to set them properly.  Plus, there is room acoustics for a little reverb.

In a chain with Eleqtri-Q, it's a powerful out-of-ya-head experience!

valley_nomad's picture

The key to make DTS headphone X work is to find a true generic HRTF that is suitable for everyone. We have been told that HRTF is almost like fingerprints that is different from person to person. There have been many failed attempts for the generic HRTF before. The out-of-head sound image is not that difficult to get. But the hardest part is to recreate the sound location that is righ in front of you. I listened to the demo on DTS' website and I think it failed as well. 

jhwalker's picture

I checked out the Z+ iOS app with my KEF m500 headphones this evening and almost leaped out of my chair to turn down my system when I first heard the demo!  Each of the speakers were clearly positioned several feet from me, and all around the room.  I can't wait to hear a movie so encoded :)