[bruma]

I would not mind any variations in the acoustic front in the mm region, because the wavelenght of 20kHz is 1.7cm. As long as there is no disturbance or any obstacle to the free flow this should have a neglectible influence.

 

[wualta]

Off topic, but this does represent another way to move air and thus another way to produce sound, aside from the cooling function.
 
http://www.genewscenter.com/Press-Releases/GE-Cooling-Technology-As-Thin-As-A-Credit-Card-Enables-Ultra-thin-Tablets-Laptops-3cf6.aspx
 
And once again it's look-ma-no-magnets, piezo to the rescue.

 

[vid]

Quote:

http://www.genewscenter.com/Press-Releases/GE-Cooling-Technology-As-Thin-As-A-Credit-Card-Enables-Ultra-thin-Tablets-Laptops-3cf6.aspx

 
 
"The turbulent air flow of the DCJ increases the heat transfer rate to more than ten times that of natural convection."
 
I wonder to how many times that of natural convection a fan increases the heat transfer rate. 100?

 

[Armaegis]

I suppose the air-motion-transformer/Heil speakers are somewhat related... http://en.wikipedia.org/wiki/Air_Motion_Transformer

 

[wualta]

This appears to be a ducted piezo fan, and the blade simply waves back and forth at high speed, so it doesn't look like it makes use of the "clapping" motion of the Heil invention, although no reason why it couldn't down the road.
 
Air motion in the piezo fan is from the high-speed vortices (miniature tornados) being shed from the leading edge.  Make a headphone out of it and you could give it a cool name like VortexaPhone. The engineering problem is figuring out how to modulate what in electrical terms would be a noisy DC power source.
 
Here's a Boeing patent that may or may not be of interest: http://www.google.com/patents/US4834619

 

[bruma]

sorry for a dumb question - therefore even more offtopic - but what is the advantage to the devices that had a hype 5 years ago, from murato for example?
 

 

[bruma]

update to the HP-1 mods:
new earpads made of fine goatskin with visco foam:

made the hole smaller than the original (for comparison on the left side of the picture) and got a better seal to the ears and the sound is more involving and direct - like it very much!

 

[MDR30]

Got down to it and fixed my Grundigs this cold Saturday. Basically copied Ludoo's and gurubhai's damping scheme, very simple.
 
In its present state the GDHS223 sounded bland and lifeless, no doubt because the only damping, a foam disc, had turned into goo and crumbles.
 

 
 
First a clean-up to get rid of all the debris.
 

 
 
Then a disc of felt (Ludoo's 1 mm Brookmore wool).
 

 
 
A similarly shaped piece of foam.
 

 
 
Some double sided tape.
 

 
 
And finally another pice of foam, I used two layers since the foam was quite thin, and some blutak on the baffle for mass damping.
 

 
 
Initial results are very promising - it sounds excellent and goes to show what a little damping can do. It's balanced throughout the frequency range with good dynamics and air too. Will leave it like this for a while to let it settle before I decide if further steps might be beneficial. Cleaned the rest of the headphone as well - the pads and headband were in quite good condition and it's very comfortable to wear.
 

 

[Armaegis]

Quote:

Got down to it and fixed my Grundigs this cold Saturday. Basically copied Ludoo's and gurubhai's damping scheme, very simple.
 
In its present state the GDHS223 sounded bland and lifeless, no doubt because the only damping, a foam disc, had turned into goo and crumbles.
 

 
 
 

 
At first I thought you were going to be using hair for damping... then I realized it was just a picture underneath.
 
So while we're on the topic of weird, has anyone tried hair? After all... it's thin, organic, a good insulator... 

 

[kalbee]

At first I thought you were going to be using hair for damping... then I realized it was just a picture underneath.

So while we're on the topic of weird, has anyone tried hair? After all... it's thin, organic, a good insulator... :rolleyes:

Haha, glad I'm not the only one that thought that.

Hair? I'm sure having hair sticking out of vents will not look appealing

 

[Armaegis]

Well, maybe put them in a little nylon baggie or something

 

[kalbee]

I'll just throw this in here and come back to check after my exams:



Would anyone be able to teach me how to take these apart? I don't know how to remove the driver unit from the cups and these need a complete recabling otherwise unusable =/
It's one of those non-foldable TDS-15. The drivers and cups should be identical to the folding variant.

 

[nick n]

why can I see through the middle of the metal retaining plate there, is that how they came? Is there even magnets or a diaphragm in there? yikes I need to know!
 
 
http://wiki.faust3d.com/wiki/index.php?title=Image:TDS15_Drivers.jpg
 
http://www.head-fi.org/t/111193/orthodynamic-roundup/990#post_3232672
 
I hope it is just the lighting in your picture.
 
khbaur had his set apart one time he would know how to do it properly.

 

[kalbee]

Yeah it should be the lighting. The stuff between the plates are none other than the diaphragm, whose detail cannot be seen due to poor lighting conditions in the picture.
This view = the one on the left in the first link you posted. Magnets seem to be on the back side (right one in the picture). The magnets on this side are parallel to the metal plate
Though from that picture it doesn't seem like the back side would help me much in soldering, except to fit new cables.
 
:S I'll worry about this in 2 days.
 
*edited for corrections*

 

[kalbee]

Wow. Well, nick was Nick was right again. I thought there could be no foam inside the earpads but I was wrong. But what matter of state is that?! Worse then my HP-2 for sure. For now I managed to scrape all of it out and put some foam cutout I had from before.

Recabling also went well but as you can see I really didn't do these justice with the random cables from a Sony I had lying around. Maybe I'll grab a black sharpie and make it look a bit more normal. Not to mention there is no knot or anything inside to keep cable tug from breaking something :S


Because the cups are still cracked I guess, the baffle/pads still do not stay put. The left side of headband is still broken but they're still usable as-is. Assuming I wouldn't be moving too much I'd assume.

**EDIT**
Fixed the mobile auto-correct lol