Technics EAH-T700 - An Impressive High-End 2-Way Headphone
Jan 30, 2017 at 2:00 PM Post #121 of 153
there is a couple of 2 drivers full size headphones, i wonder why there is no 2 way coaxial driver headphones, if the treble driver is in the center of the bass driver, coherence will be better
 
Jan 30, 2017 at 3:09 PM Post #122 of 153
There have been a number of headphones made like this in the past, but rather than a coaxial design where the tweeter replaces the phase-plug, it is simply two normal drivers, (larger) one behind the (smaller) other.
Usually the bass driver is heavily damped, covered and only one or two bass ports lead to the ear, so even this isn't truly similar to coaxial speaker design.
However, I can think of one headphone that replicates the idea fairly closely:
Ross RE-278 has two speakers, one on top of the other, both almost fully damped on the rear-side, but both almost completely open on the front side. 
They're also jam-packed with electronics to tune the two speakers in some sort of harmony.

Honestly I think this kind of design has way too many flaws in a headphone application to be worth while, and the miniaturization of a true coaxial design would probably be a technical exercise at best.
 
Edit:
Just another thought I've had about the difficulty of miniaturizing this kind of driver technology is the driver to ear distance being a significant factor.
The further away the driver is from the ear, the less prominent mids and bass appear in volume, and the more trebly they sound (easy enough to test with any open-back headphone by pulling away the cups slowly).
In a coaxial design, the tweeter is even closer to the ear than the bass driver, which is why the vented design works best, allowing for the full air pressure of the driver through a narrow space allows for greater throw and more air flow.
In a fully open coaxial style design, there is very little throw and energy to the soundwave from the 'woofer', as proven by the Ross headphone.
 
Jan 31, 2017 at 11:29 AM Post #123 of 153
there is a couple of 2 drivers full size headphones, i wonder why there is no 2 way coaxial driver headphones, if the treble driver is in the center of the bass driver, coherence will be better

 


Do not know if you have heard the JVC SZ1000 / 2000 that is widely discussed in the Bass Headphone.
They have two drivers on each size, as well as a "bass tube".

 
Jan 31, 2017 at 2:35 PM Post #124 of 153
 
  there is a couple of 2 drivers full size headphones, i wonder why there is no 2 way coaxial driver headphones, if the treble driver is in the center of the bass driver, coherence will be better

 


Do not know if you have heard the JVC SZ1000 / 2000 that is widely discussed in the Bass Headphone.
They have two drivers on each size, as well as a "bass tube".


yes i am familiar with them, but i meant something like that in headphones
 


 
Jan 31, 2017 at 2:53 PM Post #125 of 153
  There have been a number of headphones made like this in the past, but rather than a coaxial design where the tweeter replaces the phase-plug, it is simply two normal drivers, (larger) one behind the (smaller) other.
Usually the bass driver is heavily damped, covered and only one or two bass ports lead to the ear, so even this isn't truly similar to coaxial speaker design.
However, I can think of one headphone that replicates the idea fairly closely:
Ross RE-278 has two speakers, one on top of the other, both almost fully damped on the rear-side, but both almost completely open on the front side. 
They're also jam-packed with electronics to tune the two speakers in some sort of harmony.
 
Honestly I think this kind of design has way too many flaws in a headphone application to be worth while, and the miniaturization of a true coaxial design would probably be a technical exercise at best.
 
Edit:
Just another thought I've had about the difficulty of miniaturizing this kind of driver technology is the driver to ear distance being a significant factor.
The further away the driver is from the ear, the less prominent mids and bass appear in volume, and the more trebly they sound (easy enough to test with any open-back headphone by pulling away the cups slowly).
In a coaxial design, the tweeter is even closer to the ear than the bass driver, which is why the vented design works best, allowing for the full air pressure of the driver through a narrow space allows for greater throw and more air flow.
In a fully open coaxial style design, there is very little throw and energy to the soundwave from the 'woofer', as proven by the Ross headphone.

i understand that, but look at the hd800 driver, it has a hole in the middle, there is a space for miniature tweeter, the companys can experiment with similar ring radiator driver and instal treble driver in the middle with crossover between the two, dedicated treble driver can have a lot smoother upper end, the other ting to consider is balanced armature tweeter in the middle, final audio have successful dynamic driver balanced armature full size hybrid but is not coaxial driver configuration, with ring radiator drivers coaxial configuration can be achieved
 
Jan 31, 2017 at 4:18 PM Post #126 of 153
  i understand that, but look at the hd800 driver, it has a hole in the middle, there is a space for miniature tweeter, the companys can experiment with similar ring radiator driver and instal treble driver in the middle with crossover between the two, dedicated treble driver can have a lot smoother upper end, the other ting to consider is balanced armature tweeter in the middle, final audio have successful dynamic driver balanced armature full size hybrid but is not coaxial driver configuration, with ring radiator drivers coaxial configuration can be achieved

If you aske me, the last thing the HD800 needs is more treble
tongue.gif
 but I get your meaning.
If such a ring radiator driver were designed to take care of everything from midrange-down and produce sublime, deep, textured, solid bass, that would allow room for a treble tweeter.
But when you look at what single drivers can already do when properly tuned, there doesn't seem to be much point... but hey, it's not like we've heard one in action, so maybe you're onto something :D
 
Jan 31, 2017 at 4:35 PM Post #129 of 153
  i also will make planar electrostatic hybrid, planar have excellent bass, electrostatics have excellent mids and treble

Bi-amped and ready to empty your wallets! how's that for a company slogan?
 
Feb 16, 2017 at 5:44 PM Post #131 of 153
I got to spend a little time in our studio with the Technics EAH-T700 earlier this week and I have to say it's certainly an attractive headphone and the packaging presentation was incredibly well thought out. Haven't done much listening with it, but I definitely wanted to share these shots with you guys.
 

http://www.head-fi.org/g/a/1137230/technics-eah-t700
 
Mar 25, 2017 at 11:36 AM Post #135 of 153
Picked up this headphone from a site in the UK where they were getting rid of a demo for an amazing price. They just arrived yesterday so listening impressions are very preliminary. As a side note build quality on these is very high.

Source was a Teac pd-501 hr cd player into a COS Engineering H1 dac/headamp (amazing product that deserves more coverage). While the Teac is warmer and less detailed than my usual transport (a Tube Technologies Fusion 64) it is actually not a bad unit with a smooth, natural signature. So far I have only listened to well recorded jazz CDs: poorly recorded fare might result in a different impression.

My preference is for a mostly neutral, detailed sound with a slight bass lift. For reference my other main cans are: AKG k701, Hifiman He 400s, Noble k10ua, Etymotic ER4S, LA900 and Focal Utopia.

In a nutshell the Technics is one of the more fun listens I have had in a while despite their clear deviation from neutrality. Yes the Technics are definitely not "flat" but I mean that in a good way. There appears to be a slight upper bass hump that subjectively would likely obscure the lower bass in a less than ideal setup. Female vocals are presented up front and forward in a way that enhances detail in this area. However there seems to be a dip in the upper midrange to lower treble transition that pushes some instruments a little further back in the mix than they should be. Upper treble extension apoears to be good, but perhaps could sound slightly disconected on some systems. Tape hiss is noticeably accentuated. Staging is also good, but since I am less concerned with this than many appear to be I'll leave it at that. However nothing I have said takes away from my enjoyment of these cans.

Somewhere along the line in this hobby some appear to have become obsessed with technicalities as opposed to just enjoying the overall voicing of the unit and accepting it for what it is. The Technics apoears to be an honest expression of the way the lead designer hears or wants to hear music as opposed to an attempt to match sone target response.

One final comment: the What HiFi review savages this headphone giving it only 2 stars. While one cannot argue with the subjective impressions of the reviewer (I have to assume they heard it as described) I must question the weight they have applied to each noted issue. When taken as a whole these cans are definitely a much better listen than their rating suggests. I can only assume that either my impression is too preliminary (I was told my unit was a display demo so I have no idea how well they have been broken in) or the What HiFi reviewer's listening chain (including their ears) was not ideal.

Hope this has been helpful. Now back to listening ....
 

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