
Ear Speakers – Research, Design, and Evolution - mxfh
https://www.valvesoftware.com/en/index/deep-dive/ear-speakers
======
wallflower
If you are interested in software-driven headphones, the Smyth Realiser series
has always fascinated me.

[https://smyth-research.com/](https://smyth-research.com/)

[https://www.cnet.com/news/smyth-realiser-a8-perfect-
surround...](https://www.cnet.com/news/smyth-realiser-a8-perfect-surround-
sound-over-headphones/)

[https://www.soundonsound.com/reviews/smyth-research-
realiser...](https://www.soundonsound.com/reviews/smyth-research-realiser-a8)

~~~
bonestamp2
These things are awesome! They used to ship the A8 with STAX Ear Speakers...
which when I discovered it almost 10 years ago was the first time I had ever
heard the term "ear speakers" or had ever heard of electrostatic headphones,
or the brand STAX (from Japan). All in all, The Realiser and the STAX were
unbelievable! I got bored of the A8 after awhile but I never got bored of the
STAX... I wish electrostatic headphones were more widely available in general,
they're a true gem. Everyone that hears them is in awe.

~~~
Azrael3000
And they are "easy" to build yourself. I wrote a guide about doing so here [0]
which is based on this enormous head-fi thread [1].

0: [https://github.com/Azrael3000/headphone-
guide](https://github.com/Azrael3000/headphone-guide) 1: [https://www.head-
fi.org/threads/my-diy-electrostatic-headpho...](https://www.head-
fi.org/threads/my-diy-electrostatic-headphones.498292/)

~~~
wallflower
Wow, very impressive to DIY! It is one thing to do speakers DIY, quite another
to make headphones, let alone e-stats.

For those who are interested in entry-level, non-DIY route

Drop (formerly Massdrop) has their variant of the classic Koss ESP/950
electrostatic headphones for around $500. They sold out earlier this year.

[https://drop.com/buy/massdrop-x-koss-
esp-95x-electrostatic-s...](https://drop.com/buy/massdrop-x-koss-
esp-95x-electrostatic-system?mode=guest_open)

------
dmix
> Humans in general are very sensitive to sounds within 2kHZ-5kHz range. If
> the frequency of a virtual sound doesn’t match up to what we expect it to be
> in reality, then we are more likely to identify the sound as “not real”.
> This is particularly true if you compare how easy it is to tell if someone’s
> voice is broadcast through a speaker vs. someone is talking beside you.

I never thought about that in regards to gaming or even conference room voice
chat, it is extremely easy to tell the difference. Must be a challenging
problem set to solve, sounds fun!

------
voldacar
These look really interesting! I own an original AKG K1000 from 1989 and they
definitely have a better sense of "solidity" and "presence" than ordinary
headphones with drivers that seal against your head, due to the natural
crossfeed.

Other than the K1000 successor that got released a year or two ago (mysphere
3) there has been very little development since then in the field of open-air
driver headphones. Hopefully these can sound good without breaking the bank!
Also this is the first headphone that uses a driver based on the BMR principle
that I am aware of

~~~
falcolas
HiFiMan has a series of open air planar magnetic drivers, and they're
absolutely awesome to listen to. I've yet to find other headphones that can
stack up. Their only downside is the weight.

~~~
voldacar
Which Hifimans are you referring to? Just to clarify, I'm talking not about
open-back headphones, but headphones that don't have pads and consequently
don't form a seal between the ear and the driver.

~~~
falcolas
There is no seal. A seal implies a lack of air movement and sound isolation
associated with closed back headphones. Open back headphones have no sound
isolation in or out. The parts that contact around your ears with HiFiMan's
simply set the distance from the driver to your ear, in a comfortable way.

~~~
voldacar
That is incorrect. When I say "seal", I am referring to the sealed cavity
_between ear and driver_ , not to anything behind the driver. This is actually
quite important for planars in particular, as a broken seal between the ear
and driver leads to rapid bass rolloff, due to the lack of excursion found in
most planar drivers (ime this is most noticeable with audezes since their
excursion is especially low but I notice it with my HE-6 when I don't have the
pads on my head quite right and there's a tiny gap between my head and the
pads somewhere)

~~~
p1esk
What would be the sound difference between such open-air headphones (no seal
between ear and driver), and placing my head in between regular speakers (few
inches distance, ignoring comfort concerns)?

~~~
voldacar
Well for one, most speaker drivers aren't designed to cover the full range of
20hz-20khz, something headphone drivers are explicitly designed to do
(historically there have been a couple of multi-driver headphones, but they
were horrible without exception). Even a high quality midrange driver for a
speaker will probably only have a good response between 300hz-5000hz and past
the upper frequency limit you will get major treble spikes and rolloff due to
the cone entering its breakup mode resonances, so it will sound predictably
awful. Now there are fullrange speaker drivers, but these do not generally
have flat response characteristics as they tend to roll off early on both ends
of the spectrum, and fullrange drivers with multiple cones (aka "whizzer"
cones) tend to have a breakup spike in the upper mids at around 3-5khz. I am a
little less sure about the physics of this part, but I believe that even if
you had a theoretically optimum speaker driver, you would run into Q-factor
related issues because speaker drivers are meant to be listened to in the far
field rather than being placed right up against your head, so if you had the
driver right next to your head, your eardrums would see a huge FR spike in the
midrange, due to a resonance/standing wave forming in the cavity between your
ear and the surface of the driver. Headphone drivers, since they are designed
to be placed up against the ear, are usually damped, mechanically or
electrically, specifically to avoid this. The K1000 in particular is damped
electrically (there's a small notch filter (?) on a tiny pcb that feeds the
driver) since its sensitivity is already very low with the little amount of
mechanical damping it has. One common issue between something like a K1000 and
a headphone made with open air speaker drivers (no baffle or box behind the
driver) is that they both experience rear wave phase cancellation at very low
frequencies, which causes a 12db/octave rolloff below the primary resonance of
the driver. This is due to the negative wave from behind the driver wrapping
around to the front of the driver and decreasing the amplitude of the positive
wave.

TLDR speaker drivers, compared to purpose-built headphone drivers, are highly
sub-optimal due to limited FR range, breakup modes, and Q factor / improper
damping for the application. Directivity and near-field effects (both of which
would further distort FR) would probably also be an issue with speaker drivers
but I don't know of anyone really trying to build a high quality headphone
from speaker drivers so I can't comment on that.

~~~
p1esk
Thank you, that was very informative! How did you learn so much about audio?

I use Sennheiser HD600 at home (mostly for classical music), and Bose QC-15 at
work (mostly for pop/rock/electronic). I also have Grado SR125, but I rarely
listen with them, because they are not very comfortable, even though the sound
is pretty good - they feel more dynamic and lively than HD600, but that could
be due to the difference in impedance (the source is Macbook Pro, which might
technically be to weak to drive HD600, I'm not sure).

Based on this information, would you recommend any other headphones for me to
try?

~~~
voldacar
I've just been an audiophile for a long enough time I guess. The HD600 is
great, it is endgame for many people and routinely beats headphones costing
several times as much. Grados I quite dislike, they have really high
distortion in the bass and have audible ringing at around 2-4khz. But if you
like them, you do you I guess. The HD600 is in a unique spot where there are
really no headphones out there that are a direct upgrade across all areas. Its
main weaknesses are bass extention and dynamics, something like an hd800 or
focal utopia (both of which are pretty different from one another) will beat
it squarely in both of those areas, but those two headphones don't have the
highly flat diffuse-field tuning of the hd600. If you like the hd600 and
grados, you probably prefer a drier tuning, so a non-exhaustive list of some
headphones you should try might be:

Focal utopia - These are somewhat v-shaped, extremely resolving, possibly the
most "dynamic" sounding headphone, very narrow like the hd600, makes hd600
sound veiled and compressed in comparison.

Sennheiser HD800 - Definitely a polarizing headphone, bright in the lower
treble but lacks some presence due to a scooped upper midrange @ around 2khz,
so the opposite of grado in that regard, super enormous stage (second only to
K1000) but imaging is not quite as precise as utopia or K1000. Great bass with
minor rolloff, makes any hd6x0 sound wooly and imprecise. Extremely resolving.

AKG K1000 - Their presentation is a lot more like speakers than headphones.
Very unique and incredibly "live" sounding. They are forward at 2khz but not
as much as grados. They can sound alive and dynamic, or washed out, dead and
veiled, all depending on the angle of the drivers, so you really have to
adjust them perfectly to see what these can do. More resolving than hd600 but
not as much as modern flagships like the two above. They have the widest stage
of any headphone, it really has to be experienced. It's as if there are
actually palpable instruments floating in the space around your head. Amazing
realism, but highly uncomfortable and not ergonomic in the slightest. Ones
with serial #s below 5000 are the most desirable as these are the "bass heavy"
versions which were made before a factory revision that increased the primary
resonance of the driver from around 40hz to around 60hz if i recall correctly)

Mysphere 3 - Modern K1000 successor, designed by the same guy who designed the
K1000 in the late 80's. I have not heard them but they are said to improve on
comfort, resolution, bass extention, and driver sensitivity.

I would be cautious with planars. When they aren't tuned to sound like
listening to music through a sock (audeze) they often have a weird habit of
sounding simultaneously bright and veiled, which isn't exactly pleasant. Not
sure why that is from a physics standpoint. the diaphragms are usually held to
high tension, so it might have to do with standing waves forming on their
surface at high frequencies? Idk. What planars excel at is mostly their
unmatched low frequency capability, with bass extention flat to well below
10hz with a perfect seal. Good planars tend to have a sense of huge weight and
solidity but without the bloatedness and blurriness of bassy dynamic
headphones. My favorite planar is the hifiman HE-6, but the driver has a lot
of ringing in its stock form and needs to be modded to reach its full
potential. Also the drivers have a nasty tendency of dying, and I don't think
the manufacturer can replace them anymore. Like the K1000, they are also
extremely insensitive. I unironically use a speaker amp to drive these. If
what you want is an upgrade in terms of resolution, planars probably aren't
where you want to look, as they usually have some degree of haziness to them
that you don't find with dynamic drivers.

Any stax - These are electrostats and require their own high-voltage amps.
There are warm stax (sr-007, sr-L700) and bright stax (sr-009) but generally
speaking they tend to be highly resolving but dead sounding and lacking
dynamics. This might be due to the limited excursion and low driver mass,
again not 100% sure why. Also they tend to have an upper mid shelf (wider than
the narrow 2khz-ish boost present in AKGs and grados) from around 1000hz
onward that lends everything a kind of plasticy timbre. They are really cool
from an engineering standpoint but in my opinion overpriced and not that
musically engaging.

For your preferences I would stay away from: Audeze (veiled compressed dead
sock), non-flagship hifimans such as he-500 and he-560 (veiled and hazy to the
max), anything mrspeakers (grainy compressed dead sock, also veiled), ZMF
(legitimately nice sounding boutique dynamic driver headphones, but definitely
colored and significantly warm of neutral), the senn hd700 (truly an abortion
of a headphone), the hifiman HE1000 (veiled, warm, wide, sounds like listening
through two cellphone speakers placed 6ft away from your head), and any fostex
dynamic drivers (highly dynamic and v-shaped, opposite of hd600)

Most of these are really expensive and/or unobtanium, but as I said you have
to do quite a bit to beat the venerable HD600. It would be crazy to buy any of
this stuff blind, I would recommend finding a local high-end audio shop where
they will let you sit down for a few hours and listen without interruption.
Head-fi meets are also a great opportunity to listen to a bunch of gear and
meet new people, I'm not sure how often those occur anymore though. Cheers!

~~~
p1esk
I appreciate the detailed response!

What kind of music would you recommend listening to to evaluate headphones in
a shop? I plan to grab my HD600 and Grado and compare them to HD800. Aside
from Sennheiser and Grado, my local shop lists the following:
[https://www.missionaudiovideo.com/catalog/headphones-and-
wir...](https://www.missionaudiovideo.com/catalog/headphones-and-wireless-
systems?category_id=935&manufacturer=35,19891,31230,27186,8809)

I was told the high impedance can be an issue when listening from a
desktop/laptop/phone (as I normally do), so I was actually considering HD660S
or even HD598/599\. What do you think?

What about in-ear models? I hate the fit of the stock iPhone earbuds (they
just don't fit me at all), but provided I find those that fit well I would
like to own high quality earbuds. What's the difference in terms of sound
between in-ear and around the ear designs?

~~~
voldacar
Listen to anything you like that's well mastered and in a lossless format.
Acoustic music recorded in natural spaces tends to reveal the capabilities of
a transducer better than synthetic or overly close-miced recordings do, in my
opinion. Classical and jazz tend to be most useful here because they tend to
escape the dynamic range compression that pervades all of pop and electronic
music these days, but there is well-mastered music in any genre. Any music you
are super familliar with will basically tell you all you need to know really.
A few albums I like to listen to when evaluating gear are Pat Metheny Group -
The Way Up, Aphex Twin - Selected Ambient Works 85-92, and Miles Davis -
Bitches Brew (not the remaster).

I don't think any of those other cans listed online will challenge the HD600
at all, I know the nightowl and se-master1 are both notoriously bad. But if
they have an HD800, definitely go have a listen. It is a polarizing headphone
and whether you like it or not will tell you a lot about your own preferences.

High headphone impedance is only an issue if the source you're listening out
of has a high output impedance, if the output impedance of the source is high
enough, the frequency response will be altered and there will be a FR bump
around the primary resonance of the driver (usually around 100hz in most
dynamic drivers) due to a lack of electrical damping. A dedicated headphone
amp is always best, there are a lot of good ones out there these days that
don't break the bank.

I'm not an IEM expert, I've never really felt the need for them and have never
found a comfortable pair either. Over-ear designs should have more spatial
realism as the sound field interacts with your whole ear (research HRTF and
pinna transforms if you want to learn more) compared to IEMs which fire
directly into the ear canal and so skip the HRTF entirely.

~~~
p1esk
What do you think about Apple Homepods?

~~~
voldacar
Haven't heard it. I know a lot of people were hyped up when it first came out
but I don't really know if it delivered or not. It's supposed to be well DSP'd
so I wouldnt be surprised if it beat most of the speakers in its price range
though.

~~~
p1esk
I'm thinking about getting them as desktop speakers, as an alternative to
using headphones at work, because my ears get hot after a couple of hours,
even in HD600.

------
robocat
I live articles that show the process of designing completely new hardware.

I do wonder if this article is missing any dead ends; only showing the
iterative improvements?

------
neves
Looks like it will be impossible to play with someone else in the same room,
right?

~~~
rodgerd
Sure but you're already flailing around with a vision-blocking helmet, waving
your hands. Noise pollution seems like less of a hazard for a bystander than
getting whacked by the player.

------
tictoc
How does sound affect us between receiving via headphones vs a speaker?

------
cryptonector
Oh, wow, this really is cool.

------
chrischen
Elephant in the room is that it still has a wire sticking out.

~~~
GuB-42
That's not the subject. But do you really think they didn't even consider
wireless?

Turns out it is really hard. You need a low latency, reliable ~10Gbps link.
You also need the battery to be power all the that stuff. Putting everything
inside the headset would be ideal but you also have to consider that weight
affects comfort and immersion significantly.

The first semi successful attempt is TPCast but it is far from perfect. I
don't know much about the Vive wireless but it seems to work better but still
have its own set of issues. Both are also rather expensive (~$300).

So for now, we seem to be stuck with fully integrated low end or wired high
end. I think we still need to wait a bit more for wireless high end.

~~~
chrischen
I've been using a Vive with the official wireless adapter and it works
flawlessly.

The subject is immersion.

My point is that with all that goes into making the audio immersive, the wire
out back instantly defeats any gains there.

------
dsr_
I wonder if the F/R graph has been pre-corrected against human perception?

It looks really flat -- and you'd ordinarily think that was good, but it turns
out that humans don't have equally sensitive hearing at all frequencies. There
are a range of curves from different studies, and most musical transducers
pick one of those curves and try to emulate it in hardware, so that a smooth
frequency sweep from low to high continues to sound equally loud.

Perhaps Valve is planning on adding that through digital equalization.

~~~
atoav
It is _worse_ than that, the curve of human hearing is not only everything
else than flat, it also _changes with volume_.

~~~
JohnBooty
One thing to note is that it's not all doom and gloom. Unless aiming for a
full VR positional audio experience like Valve is doing here, an audio
playback system (headphones, speakers, etc) doesn't have to compensate for all
of the various nuances of human hearing. After all, sounds "in real life"
don't do that.

All an audio playback system needs to do is reproduce the original sound
accurately, perhaps with some Fletcher-Munson compensation to enhance bass at
low listening volumes.

(Interestingly, this sort of feature was present on home stereos for several
decades. The poorly-named "loudness" knob increased bass so you could enjoy
satisfying bass without increasing the overall system volume...)

~~~
KozmoNau7
The loudness button's functionality lives on, in an improved form. Any
reasonably modern AV receiver with Audyssey or equivalent room correction/DSP
will apply dynamic EQ based on the volume setting, to compensate for volume-
dependent frequency sensitivity.

It's a great way to get speakers to sound "bigger" than they are, at volume
settings.

~~~
JohnBooty
Audyssey is absolutely wonderful. It makes a dramatic difference and is light
years ahead of a simple loudness knob.

However, I have to wonder - for those with Audyssey-equipped receivers, what %
of owners bother to complete the setup process with the calibration
microphone? I suspect that number is unfortunately low. :-/

Also, I don't think too many people listen to music on AV receivers these
days. The product category itself seems to be fading.

Home theaters have swung toward soundbars, and music is listened to on
computers, mobile devices, and/or Bluetooth speakers.

I'm saying this as a pretty old-school stalwart myself, with a fairly capable
AV receiver in the living room for video and a bunch of audiophile-ish two
channel gear for music.

~~~
KozmoNau7
I don't think the AV receiver is going away anytime soon.

Just like what has happened to stereo amplifiers, what is happening is that
the opportunistisk low end of the market is moving on. Cheap radios,
turntables and amplifiers were replaced with cheap plastic mini/micro stereos,
which were in turn replaced by all-in-ones, which were replaced by bluetooth
speakers, and so on.

Cheap AV receivers and especially cheap home-theater-in-a-box type products
have been replaced by sound bars, which I would say is actually an improvement
in a lot of cases. Some of the low-end AV receivers that were on the market in
the 90s and 2000s were unmitigated garbage and a waste of money.

Quality fifi separates live on, and you can still buy mini/micro stereos and
all-in-one radio/media player devices. You can still buy AV receivers, but the
worst cheap ones have disappeared. I'm not sure you can actually buy HTIB junk
anymore, but good riddance to that rubbish.

The appreciation for good sound lives on, but the more complicated devices
move to more of a niche role, sticking around for those of us who desire
really good sound, and don't mind a bit of a complicated setup process. For
everyone else, a sound bar with a wireless subwoofer gets them most of the
way, with significantly less effort.

Listening on a computer is simply the next replacement for turntables, tape
decks, CD players, DVD/Bluray players, standalone streaming devices and so on.
My primary media source is an ultra small form factor PC streaming FLAC and
DVD/BR rips from my NAS, hooked up to my receiver over HDMI. It's almost too
easy to get amazing sound quality today.

Similarly a smartphone will produce great sound quality with decent source
material. The playback device has become a footnote, they're all capable of
great sound quality today, as long as you pipe it to something higher quality
than a cheap soundbar/bluetooth speaker.

