[khbaur330162]

Planar speakers have huge radiating surfaces compared to headphones and even at that they seem to have trouble producing sub-500Hz. It's at least interesting, imo, to see others having many of the same ideas that I've been toying with in my mind. These are just my 2 cents at bridging the gap between electrostatic fidelity and being able to use a standard amplifier. I'm basically aiming for a top-notch isodynamic headphone with top-notch spacial queuing that's not $1k. I'm sure many people are thinking they already have that, but I don't.

 

[rhythmdevils]

Does anyone want to build a YHD-Nova? 
 
I've got all the parts for another one but dont really want to put it together.  Baffle, YHD1, headband, and L brackets with screws.  You'd need putty to hold drivers and earpads.  I haven't totally worked them out yet, but they have potential.  Would offer it for cost of parts of course....

 

[maverickronin]

Quote:

Planar speakers have huge radiating surfaces compared to headphones and even at that they seem to have trouble producing sub-500Hz.

That's all backwave cancellation though.  If you mount the driver in an infinite baffle configuration or something, like in a wall with all the backwave vented outside, there won't be any roll off.  That's amazing impractical most of the time but it will work.

 

[badbod]

Huge thread, missing an important facet.
 
While static magnetic fields have little interaction with the human brain. Moving magnetic fields do.
 
Perception is an important part of subjectivity. 
 
Ortho's place a fairly large magnetic moment close to the brain, then move it. This will affect your perception. There may be controvercy over health implications, I beleive magnetic moments, unless hugely disturbed, have no health implications, due to thier ubiquity in nature; but it is a simple fact that high intensity moving magnetic fields close to the brain, affect perception. 
 
Given this, would it not suggest that this is in fact the future of headphone design, health aspects ruled out? Headphones lack the bass response of the hairs on your arms and legs being moved by the oscillating air, the very skin of your body feeling the pressure waves. Is it not then possible that those moving magnetic fields placed closely to the brain, we know affect the brains perception, may 'simulate' exactly that?
 
Food for thought?
 
Regards
David

 

[crimsonOkami]

While out searching for custom grills for my future speakers/headphones i came across this:
 
http://www.reliablehardware.com/customspeakergrill-116diastaggered.aspx
 
It might be a good baffle for a headphone, but personally I'm afraid that the spacing might be a bit too far apart to provide good transparency since it's at 25% open air, but at least it doesn't cost as much as the coffee filter per area.

 

[khbaur330162]

This is what I was looking at:
http://www.amazon.com/Aluminum-3003-H14-Perforated-Staggered-Spacing/dp/B000H9TJGU/ref=sr_1_30?ie=UTF8&qid=1331207128&sr=8-30
I think it's around 40% open. The stuff you're looking at should be fine.
 
 
badbod - No, I don't believe that's the case. The magnetic fields these create aren't MRI level, or anything. The amount of mass that they have to move is roughly in the order of the mass of the total volume of air inside the ear chamber, whatever that's worth. And given the inverse square law I think it's safe to say your brain is far enough away to exclude any placebo-esque stimulation. If you're wondering about ortho's don't ever buy a pair of plasma headphones! And if the future of headphones is "altered perception," you just opened a whole can of worms. Ever had a few glasses of wine while listening to your rigs? Recommended. 

 

[crimsonOkami]

Quote:

I think it's around 40% open. The stuff you're looking at should be fine.

 
pretty close, 41% open.  The perf sheet from the same supplier as yours with 3/32 holes is only 21% open air.  If anything i'm probably going to get the 1/16 sheet and experiment with that, maybe make the holes bigger.  I think that it has enough closed-ness to support enough area for the magnets to do their work.  Don't wan the magnets loosing too much of their strength.  It'll probably be easier than trying to make a baffle out of delrin sheet, but then it won't have that "golden ratio" design.  decisions decisions...

 

[wualta]

 
Quote:

That's all backwave cancellation though.  If you mount the driver in an infinite baffle configuration or something, like in a wall with all the backwave vented outside, there won't be any roll off.  That's amazing impractical most of the time but it will work.

Yep.
 
Siegfried Linkwitz publishes plans for speakers with dipole woofers. He's using cone drivers, but the idea is the same. The back is open, but the sides help contain and delay the backwave very much the same way we try to do in our open headphones.
 

 

[khbaur330162]

Okami: You're contemplating damping the drivers with your magnet structure? You'd just need to constrict airflow noticeably at the center of the diaphragm. The golden ratio image helped get me to think about and realize this. 20% open would probably be too much if you wanted to try this. If I were you I'd get a pair of drivers working first. It also might be easier to buy two grades of perforated sheet metal and make a hybrid design i.e. 40% open and glue those coffee filters (cut down to ~1" if needed) on top. 
 
 
http://www.diyaudio.com/forums/planars-exotics/98168-search-very-thin-open-pores-foam-layers.html
Here's another guy looking into foam to tame resonances of planar diaphragms. The only problems these guys seem to be able to foresee is decomposition of the foam, decreased sensitivity and a negative impact on FR (field density loss, or something else, Idk).

 

[vid]

Got around to symmetricalizing my mods on the HOK.
 
This is the channel balance before and after (centered at -20 dB, up means left and down is right):

 
The HOK seem reasonably well matched in the channels even with my mods botching it up; but cutting up the felt donuts to be symmetrical etc. improved the lower frequency balance quite a bit. It's still a bit off, but not too badly.
 
I didn't do a careful before-and-after comparison, but I think the sound changed a bit. Bass seems a bit more detailed, and imaging seems a bit more precise – as if the soundstage became better-defined, opened up. Also, for unknown reasons, the sound seems less harsh... I said before that the HOKs sound a bit clinical, and I think some of that clinicality is gone. But this could as well be due to my imagination/time of day/whatever.

 

[wualta]

The HOK lives! is it ready to come down the grand staircase and be presented to society at large?
 
Which is to ask: is the period of the modifications over?

 

[nick n]

Quote:

Got around to symmetricalizing my mods on the HOK.
 
This is the channel balance before and after (centered at -20 dB, up means left and down is right):

 
The HOK seem reasonably well matched in the channels even with my mods botching it up; but cutting up the felt donuts to be symmetrical etc. improved the lower frequency balance quite a bit. It's still a bit off, but not too badly.
 
I didn't do a careful before-and-after comparison, but I think the sound changed a bit. Bass seems a bit more detailed, and imaging seems a bit more precise – as if the soundstage became better-defined, opened up. Also, for unknown reasons, the sound seems less harsh... I said before that the HOKs sound a bit clinical, and I think some of that clinicality is gone. But this could as well be due to my imagination/time of day/whatever.

YAY  wow those are some good measurements.  Of course the mods aren't over... I still have to send some special foam that way.

Did you seal up all the "interfaces" with putty, or are these open backed at this point I can't recall?
 
 
Speaking of "off" I know how it must feel with that . To go through all that work then trying the things and oooh noooo. The fact you noticed it will even make it more noticeable

Just finished up the latest SFI 32 mod seen below, and think one of my ears isn't fully functional, I can feel it, so I am getting a slight channel imbalance also.
Thinking that between letting these never-before-run drivers go for a bit to stretch and yawn after being asleep for all these years may also help, also generous Deoxit and a bit of fine steel wool on the plug, that's about all that can be done for now. The multimeter showed them as being within an ohm or so of each other.
 
Pretty sure ( damn doubts ) all the materials matched and were fit together equally. pretty sure....was something forgotten ( looking at a pile of foams strewn about and changing memories by doing so ).
 
This particular thingy seen below , the STUDIO TANS (any other Zappa fans out there?) are hand cut alder and hand sanded to final shape so don't look too close.
The pads, headpiece and wiring are from some goofy old SEARS pair from the late 70's ( volume controls on sides ) Hey at least the headband is real leathah. Pads possibly they sure are soft. If it were pleather pads they would have gone the way of all old Sansui and Koss by now. Donor set cost $2. Two measly dollars. Got a Sony DR-5 for 2 bucks as well for possible harvesting.
This is back in the day when they used real wires inside, copper stuff you can actually solder up nicely, not the wispy imperceptible wires you need an electron microscope to see.
Used Acousti 3 layer disc adhered in the very back of the cups, then 2 discs of motherboard ( very soft large open celled )foam for a spring to hold the other driver damping disc of acousti tight against the driver. This  Acousti 3 layer damping disc has had the back adhesive layer carefully removed to allow for pass-through of sounds( so it doesn't act as a giant reflex disc obviously )
 
All cabling entry points, even though they were snug, were sealed with clear silicone, Bass ports I went with the 5/32 again -pretty sure have to check again-same as the other Woodies I made before. Same chamber dimensions inside and similar build so why not.
Pads secured to the front with rings of double sided tape cut out of a sheet of the stuff
 
 Nice bass and same more-than-excellent clean full sound as the HOK's and Pioneer LOOPS which also use the Acousti directly on the driver rear. It's magic stuff I tell ya. Maybe I'll go make a hat with all the extra felt that's not being used around here now.
 

 
uuugh Just figured out the channel imbalance. While swapping left to right balances I heard stuff from both sides huh

. While soldering up the stuff I just assumed the way the wiring was routed that the red was right+, yep and the white was common . So unscrewing the TRS housing I see the mistake. At least I can remember what wires went where inside the cups. Off to swap some wires in the plug. Now I'm totally confused hope I can fix this. The stock wiring to the right side had red and white instead of what should have been red and black. Have to pay attention next time.
Fix't. Resoldered inside TRS plug swapping common with right channel. I know even that's confusing to you I bet. AT least I know what went wrong.
 
This is the first time the complete project has been done the first time with no need fro further mods. Not used to that.
 
 

 

[khbaur330162]

Beautiful.

 

[nick n]

khbaur:
I noticed you did up a Sony CD-380 with an ortho driver. I've had one of those sitting around for a few months thinking of doing the same thing, but for some reason the fit is very selective, has to sit in the exact right position on my head. And that doesn't feel right when it's there. It's a goofy build design for sure, what have you found with that fit aspect?
 
I see you made some pads for it too. Did you find any that were ok feeling/fitting before you made your own up?
Another thing that turned me off was the huge seam around the baffle that seems to be needing a ton of sealing up ( the part the pad backings tuck into. ) 
Any thoughts on this are appreciated, it does seem a worthy shell except for the wierd fit position and pads issues.( angled driver mount, self adjusting headband, decent cabling, fairly sturdy all around )
Any chance you could post some pictures?

 

[vid]

I think my HOKs are reasonably done, as far as anything ever is. New pads are needed at some point, and I might experiment with the paper covering the driver. Right now I still have my exam notes stuffed in there.
 
I don't have the baffle sealed right now. I'm keeping it that way in case I need to open them again soon.
 
It's possible that the less clinical sound I'm getting now is due to the new felt donuts I made. I found out earlier that using a donut instead of a hole-less disc increased the attack, but making the hole too big/small weakened the effect. The hole in the new donuts is a bit smaller, which might possibly contribute a less attack-y sound than before.