Orthodynamic Roundup - Page 453

Preliminary results of SFI transplantation to vintage Audio Technica frame: these 125 ohm suckers are really really inefficient. With the Fostex T50RP I have the volume on second to lowest in Windows on this laptop. With the SFIs I have it on max.

Here are links to 1MB scans of the Fostex brochure. 1MB is the limit for the free photobucket account.





Here are links to full scans

Back with text - 5MB

Front with picture - 6MB

Edit: This must have been right before they came out with the next generation. They already are using the RP name and the logo that is on the back of the cups.

Very interesting brochures. Too bad they are not as informative as Yamaha and don't go into more details like diaphragm and magnet construction.

maybe I'm just feeling wary of suggesting strange things, having again made the mistake of disagreeing with someone on AK.

Looks a bit like T10 driver as well.

Oh, they were discussing the application of felt to tweeter baffles to damp reflections, and i objected to the logic that since one person with some diagnostic instrumentation found that one product was better than another, and the better product was 75% wool and the lesser product synthetic, this obviously means that wool felt sounds better than non-wool felt.

the back and forth is still making me twitch.

"But product A *IS* better than product B! And product A was 75% wool SAE F-13!"

"Product A is better quality / more suitable than product B, but this does not mean that all products made of the same things as product A are always better than things not made of the same things as product A. And the SAE felt standards are 40+ years old, and don't tell us anything other than 'hey we have some felt, and we can tell you that if it bears this mark it has this wool content, and what the tinsile strength and impact deflection are. And F-13 is what we recommend for acoustic damping and fuel oil filtration. - they don't tell us why or how it's good at acoustic damping or filtering fuel oil."

"BURN THE NONBELIEVER!"

"Look all I'm saying is that you don't have to eat ivy to produce fibers useful for this job. 'synthetic' is a big wide field of fibers with all sorts of different properties and lots of them are way better than acrylic craft felt. I particularly recommend rayon. And there's a big wide world of extruded synthetics out there that the SAE people never dreamed of."

"BUT PRODUCT A WAS BETTER! WHY HAVE YOU SUGGESTED NO ALTERNATIVES?!"

etc.

Eric, tell those AK guys that the real audio felt Nirvana is in cashmere fabrics. Wool is for cheapies.

I'm a super cheapie, I use craft felt most of the time.

Wow, these Audio Technica SFIs are super bright, and super fast, with slightly less bass than I would like. Now I know what overdamping is like. All I did was leave the sticker ericj put on as a reflex dot and put a piece of superfelt behind that, with some foam behind that. Once I make the reflex dot smaller, I can easily imagine these to be a cheap self-made SR-X. I bet I can ask you guys for some help increasing the bass though. How would I go about doing this (besides removing the felt behind the driver, in other words something housing or pad related)? Also, I don't have a good way of fastening the driver to the housing, I'm just using some bluetak and the pressure of the foam right now. Any ideas for that?

Edit: Ooh, Wharfedales! Also, I'm first post again...

Edit 2: For future reference (mainly for myself), this is a 124-ohm SFI driver transplantation into an Audio-Technica AT-702 frame.

Mods:

Configuration: Foam -> Disc of superfelt -> Reflex Dot -> SFI driver bluetak'd to frame

Replaced foam in earpads with thicker foam because stock was too thin and my ears were hurting from being pressed into the plastic.

Edit 3: Forget the reflex dot, I'm currently EQing a slope in the treble down to -6dB at 20kHz.

If you want to be dead sure that the pads seal and isolate well, you can always make yourself a pair of wu-pads of leather. As for now, are you sure that no bass leaks through that foam in the earpads?

Then if you are worried about the seal between driver and housing, you can also try a thin (but springy) foam gasket in addition to the blutak.

As we are touching the subject of cashmere/wool/synthetic felt, I am almost out of the cashmere blend I and some of you have used to damp the Yamas and other orthos. It's out of production (the company was bought by a mega-corp a while ago) but the store still had (hopefully has) some. The problem is, what they have is barely enough for a coat, and they will only sell it as a whole piece. Is there any interest in a group buy of the last stock left? If we manage to gather 10 interested people, it should amount to 10 euros each with shipping, maybe less.

You can count me in on a piece of that coat :-)

It was just a minor tweak... (?)

Here are the pictures that I promised, that casts better light on the HOK, in the cold snowy north.