[Hutnicks]

Quote:

It's normal to have a bias, but useful to try to work out of it.

 
It is not a matter of bias at all. It is purely a matter of cost benefit analysis. For the life of me I cannot see the value in putting that much RD effort into a dust cover.

 

[Armaegis]

That quote in the first link about rubbing the mylar for 30 hours is interesting. Lightly crinkled/creased will add stiffness up to a point, but such extensive working of the material will result in an overall softening.

 

[khbaur330162]

The AT-707 sweat screens are along the lines of Aluminum leaf. Not sure if that's self evident from the picture I took, that's not an odd reflection, it's metallic.
 
As for the ECR-500's, it is hard to see the crinkles from my photo, you're right. This one's better.

 
 
It has to be low tension. Imagine if Sony put a patent on a scalene pentagonal diaphragm and then shot themselves in the foot with a circular sweat screen that produced all sorts of resonances of its own. *dunce hat*

 

[vid]

Thanks for the clarification, khbaur.

 

[vid]

Used thinner material and was more careful with making the folds.
 
 
 
 
 
 
 
First CSD without the material, second with. Changes are partly within measurement error I'd say.
 
Could probably stretch it a tad looser as it seems to have reduced the bass somewhat.

 

[Vaughn]

I dug back into this project and was reminded that I had moved on and started transplant of the T50rp drivers into Koss Pro 4A housings. I attempted to remove the drivers from the baffles made specifically for the Koss cups but the adhesive was far too strong. The Koss cups were not good sounding but I love the build quality of the frames so I decided to make new cups out of clear cedar.
 
Old project; to summarize, I think wood is a much better material than aluminum for cups (at least) and definitely for baffles. Also, the hemispherical enclosure was a bit of bust due to weird resonances.
 
 

 
New project; with the help of member Nick N (thank you!) and a very useful package of filter materials I was able to get everything pieced back together and sounding great. 
Since building these I am convinced of the sonic goodness of clear cedar. The baffles are 1/4" baltic birch. I created a variable filter on the cup with some hardware store parts so I can experiment (in a somewhat linear way) with choking down the venting. I've installed a spare HD600 cable and they are sounding great. I used a little bamboo felt and fiberglass on the interior of the cups for damping and the sound is good enough that I haven't even touched the variable filters (they are all the way open at the moment, which makes the open area of the vent slightly less than stock cups.)
 
 

 

 

 

 

 

 

 

[Armaegis]

Wow, nicely done!
 
I've got the variable bass vents on my Beyer COP transplant but I'm finding that I just pretty much leave them fully open all the time. I even drilled an extra hole in the cup. 

 

[vid]

First CSD is with no dust guard, second is with the thin material + convolution to match the response of no dust guard.
 
That's transparent. Though the treble's a few dB lower overall in the convolved version. Edit: Actually, the lower treble was due to a treble-reducing EQ I forgot to disable before recording the response. Can't be bothered to rerecord, but from the previous recording one assumes more or less complete transparency should that be done.

 

[Hutnicks]

Quote:

I dug back into this project and was reminded that I had moved on and started transplant of the T50rp drivers into Koss Pro 4A housings. I attempted to remove the drivers from the baffles made specifically for the Koss cups but the adhesive was far too strong. The Koss cups were not good sounding but I love the build quality of the frames so I decided to make new cups out of clear cedar.
 
Old project; to summarize, I think wood is a much better material than aluminum for cups (at least) and definitely for baffles. Also, the hemispherical enclosure was a bit of bust due to weird resonances.
 
 

 
New project; with the help of member Nick N (thank you!) and a very useful package of filter materials I was able to get everything pieced back together and sounding great. 
Since building these I am convinced of the sonic goodness of clear cedar. The baffles are 1/4" baltic birch. I created a variable filter on the cup with some hardware store parts so I can experiment (in a somewhat linear way) with choking down the venting. I've installed a spare HD600 cable and they are sounding great. I used a little bamboo felt and fiberglass on the interior of the cups for damping and the sound is good enough that I haven't even touched the variable filters (they are all the way open at the moment, which makes the open area of the vent slightly less than stock cups.)
 
 

 
 
 

 

 
Save those Hemis for a Dynamic driver project
 
That is slick work with the clear cedar. Is the interior finished or left natural? How is the baltic birch for the baffles? I was looking at MDF for a set of baffles for a project I am considering but would rather use real wood if it works sonically.

 

[nick n]

What did you end up using there for the variable vents? Is it snug enough that they don't move around on their own?  I really like the look of the "clear" cedar.  ( Is that also known as Chamecyparis Nootkatensis / Yellow Cedar? I'll have to check.)  The lighter tone with the dark pads and silver on the arms and vent is fantastic looking.  Is a softer headband padding on the bottom in the works later?

 

[Vaughn]

Quote:

Wow, nicely done!
 
I've got the variable bass vents on my Beyer COP transplant but I'm finding that I just pretty much leave them fully open all the time. I even drilled an extra hole in the cup. 

 
The COP seems like an ideal transplant candidate
 
Quote:

 
Save those Hemis for a Dynamic driver project
 
That is slick work with the clear cedar. Is the interior finished or left natural? How is the baltic birch for the baffles? I was looking at MDF for a set of baffles for a project I am considering but would rather use real wood if it works sonically.

 
Thanks

 I applied 4 layers of wood conditioner to the inside and outside (dewaxed shellac) and then rubbed in about 7 coats of Birchwood Casey Tru Oil (a gunstock oil). Working with clear vertical grain cedar like this is much like working with a dense urethane foam. It has an excellent stiffness to mass ratio and is very easy to work with but the surface can be fragile. Applying the wood conditioner and oil went a long way towards creating a shell like surface but I will still have to exercise caution to keep them in good condition. 
 
Quote:

What did you end up using there for the variable vents? Is it snug enough that they don't move around on their own?  I really like the look of the "clear" cedar.  ( Is that also known as Chamecyparis Nootkatensis / Yellow Cedar? I'll have to check.)  The lighter tone with the dark pads and silver on the arms and vent is fantastic looking.  Is a softer headband padding on the bottom in the works later?

 
Those are some aluminum drain protectors I found at a local hardware store. I had to flatten them a bit and cut them to size. I drilled out the center hole and created a pivot point with a nylon washer and Chicago bolt (also aluminum). The bottom plate is adhered to the cup and the top plate adjusts. The friction between the two plates is enough that it can be spun but stays in place once adjusted.  I need to remake it so I can take the total vented area when fully open to something above the stock cup and be able to adjust it to completely sealed.
 
This is not yellow cedar, to my knowledge. It is a scrap I found in the bin at a local used building material store for free. It was a piece of decking that had been painted over but I could see from the end grain it would be a nice cut. I've worked with yellow cedar before and it is pretty nasty stuff (although beautiful). I'm not really having an issue with discomfort on the headband so I'll probably leave it. These frames have incredible clamp, which I actually like (it seems in contrast to most HF). I can move around the house and they stay exactly in place. I do of course look absurd vacuuming with giant wooden headphones plugged into a portable amp and my Iphone. (no photo available)

 

[MrJoshua]

Here are my freshly refurbished Yamaha HP-3 that I got from my Mum yesterday.

She has owned them from nearly new in 1976/77. The stock cables had become hard and brittle and the pads were completely cracked and very uncomfortable.

Last night, I took them apart, washed the original foam backs and scrubbed the headband and cups with a toothbrush and shampoo.

While they were drying, I recabled them and cut out some black foam (that came from an iPhone 3G box) to go behind the baffle, and then added some light wadding to the inverted dome at the back of the cup, before re-assembling.

Once back together, I added a thin strip of double sided tape around the edge of the cups to secure some Adidas blue Sennheiser HD-25 ear pads and then stuck matching blue HD-25 pads to the headband for improved comfort.

They need some serious amplification to sing (I'm currently using my new Fiio E12 at the 16dB setting at over half volume) but they really do sound rather special for a pair of 36 year old headphones! Female vocals in particular are gorgeous and the bass extension is very good.



I'm a convert!

 

[MDR30]

Here are my freshly refurbished Yamaha HP-3 that I got from my Mum yesterday.

She has owned them from nearly new in 1976/77. The stock cables had become hard and brittle and the pads were completely cracked and very uncomfortable.

Last night, I took them apart, washed the original foam backs and scrubbed the headband and cups with a toothbrush and shampoo.

While they were drying, I recabled them and cut out some black foam (that came from an iPhone 3G box) to go behind the baffle, and then added some light wadding to the inverted dome at the back of the cup, before re-assembling.

Once back together, I added a thin strip of double sided tape around the edge of the cups to secure some Adidas blue Sennheiser HD-25 ear pads and then stuck matching blue HD-25 pads to the headband for improved comfort.

They need some serious amplification to sing (I'm currently using my new Fiio E12 at the 16dB setting at over half volume) but they really do sound rather special for a pair of 36 year old headphones! Female vocals in particular are gorgeous and the bass extension is very good.



I'm a convert!

Fine work! What kind of cable did you use? Looks tailor-made.

 

[MrJoshua]

Thanks!

I re-used the original strain relief (rubber and metal bits) and the cable is something I found in a drawer and is of unknown origin. It is roughly the same length as a stock HD-650 cable and has a 3.5mm stereo plug at one end (with a screw thread for an adapter) and it used to terminate in two 3.5mm mono plugs at the other ends, which I cut off. It also has a nice plastic block just under chin level to prevent the wires from separating further... It's made of pretty substantial copper and looks like it was made for the job!

 

[Hutnicks]

Quote:

 
The COP seems like an ideal transplant candidate
 
 
Thanks

 I applied 4 layers of wood conditioner to the inside and outside (dewaxed shellac) and then rubbed in about 7 coats of Birchwood Casey Tru Oil (a gunstock oil). Working with clear vertical grain cedar like this is much like working with a dense urethane foam. It has an excellent stiffness to mass ratio and is very easy to work with but the surface can be fragile. Applying the wood conditioner and oil went a long way towards creating a shell like surface but I will still have to exercise caution to keep them in good condition. 
 

 
Aha. I am quite familiar with Birchwood Casey's products. Never thought of using them in this application though. Good thinking.