[DefectiveAudioComponent]

Quote:

Originally Posted by ludoo /img/forum/go_quote.gif You missed the "where the Sextetts have the passive drivers" bit. The frame was from a pair of K240M, so the baffles had places for the passive drivers but no drivers.

Right... so we have to wait until someone decides to mess up their expensive sextett then....

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Near as I can figure from study of the patent, AKG was trying to make a closed 'phone that had none of the sonic problems of usual closed 'phones. The passive diaphragms (not drivers) were originally meant to adjust the frequency response variations that a closed earcup would have, and those would have been mostly in the bass and low midrange, not the treble, since the passives would've needed appreciable air pressure to work, and treble excursion in a headphone diaphragm is small. That's my best guess, anyway.

The illustration on the wikiphonia says they tried to achieve a closed can regarding bass, and at the same time an open can regarding treble. The passive diaphragms are supposed to keep the bass backwave inside, but let the treble through. It sounds like an excellent idea for ortho drivers that are both bass weak and have trouble with treble. But I don't know if their idea ever really worked.

 

[Rick]

I'd say it does, Sony MDR series has a slider switch on the side of it to choose between music and movies (music having more bass than movies), when set on movies it triggered a small push tab that was normally held against the baffle with a spring, so in movie position it pulled back and opened up an openening in the baffle directly underneath the driver.

 

[Rick]

but all it really does is reduce the bass.......

 

[DefectiveAudioComponent]

Quote:

Originally Posted by fsma /img/forum/go_quote.gif but all it really does is reduce the bass.......

Yes.. but opening a hole to cancel some bass, and using a passive diaphragm (that preserves bass) is not supposed to be the same thing.

 

[Random Murderer]

Quote:

Originally Posted by fsma /img/forum/go_quote.gif anyone know how I tell which pin is pos and which is neg on the cardas sennheiser connectors?

the thicker one is neg.

 

[4lane]

I was lurking around on this forum looking for some info about my old Fostex T20s. I wanted to like them for their durability and comfort, but just couldn't because of the dull, unexciting sound. I came to learn from this forum that they're the somewhat cultish "t20v2" that you folks love to mod and talk about.

So I took the plunge, cracked them open and tried a variation of Wualta's mod (post 371). Having no source of exotic "superfelt" or "uberfelt", as a clueless noob I used cheap craft felt for the damping material. I also didn't use a "reflex disc", since I couldn't figure out what this was, though I did use the paper reflex dot. The result was a great improvement, but the bass sounded kind of boomy and not too deep.

I then had the bright idea of trying a 1.5 inch hardware store felt furniture pad in place of the cheap felt as damping material. These pads are thick (about a quarter inch) with one carpet-like woven layer backed by another layer of more densely woven material. The 1.5 inch diameter is almost a perfect fit for covering the driver. I peeled off the outer paper and adhesive layers of the pads and attached them to the back of the drivers with a small amount of electrical tape, carpet side down.

This result seems better still, with tighter, deeper bass and detailed highs. I was wondering if anybody else had tried something like this. I'm neither an audiophile nor much of a do-it-yourselfer, and don't trust my own ears as much as maybe I should. If there's something else that would make even more improvement, please let me know.

 

[ludoo]

Quote:

Originally Posted by 4lane /img/forum/go_quote.gif This result seems better still, with tighter, deeper bass and detailed highs. I was wondering if anybody else had tried something like this. I'm neither an audiophile nor much of a do-it-yourselfer, and don't trust my own ears as much as maybe I should. If there's something else that would make even more improvement, please let me know.

Thick felt sounds about right for the T20v2, as they have quite a bit of bass in stock form. I disassembled the driver on mines and put some dense thin felt directly over the top magnet held in place by the driver clamp, but I don't think it's really necessary and it's a bit messy (one of the drivers sprung open when I did this).

You can fine tune your mod if you think they could improve further, by adding lighter felts and experimenting with shapes and sizes: a smaller disc in the centre or a donut, etc. Oh, and welcome to HeadFi!

 

[malldian]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif In the LP Sextett I have, they could have saved all that effort, because the result frankly snorts. The K501, which substituted damped vents (if the glue didn't run out) for the expensive and baffle-weakening passives, sounds far less colored and Seventiesish to my ears. On the other hand, the Realistic Pro 50, which I'm told is a K250, uses its diaphragms well. The bass is missing, but the rest of the spectrum is handled excellently. So they did get it right, but the tuning would only match the driver AKG was using. Stick an SFI in there and you might get duck soup, or worse.

I have owned the LP and MP Sextett and the bass difference was extremely apparent. How did you find the Sextett colored and can you describe for the youngn's what you meant by Seventiesish?

 

[ericj]

IIRC, wualta's k240 pads are quite flat, when they should resemble a more leathery version of the T40 pads. Certainly has an impact on the sound.

Edit: and anyway, the filter patches on the K240-M are supposed to do almost exactly the same job as the sextett passives, just cheaper. Early K240-M's have a baffle that differs from an LP Sextett only in the respect that the discs that would usually have filter paper plus a passive diaphragm just have denser filter paper and no passive. Later ones have smaller holes in a smaller circle.

 

[mypasswordis]

My Philips EM6721 came yesterday. After a small bump in the treble with EQ, it sounds really great, actually. I'm going to try some standard mods like felting the backs of the cups and maybe a small reflex dot if I can figure out how to open the thing up.

I wish the seller packed better instead of just using paper, though.. the box is quite crumpled and there's a scratch on the cup.

Edit:

Quote:

Originally Posted by wualta In the LP Sextett I have, they could have saved all that effort, because the result frankly snorts. The K501, which substituted damped vents (if the glue didn't run out) for the expensive and baffle-weakening passives, sounds far less colored and Seventiesish to my ears. On the other hand, the Realistic Pro 50, which I'm told is a K250, uses its diaphragms well. The bass is missing, but the rest of the spectrum is handled excellently. So they did get it right, but the tuning would only match the driver AKG was using. Stick an SFI in there and you might get duck soup, or worse.

I had and sold malldian my MP and LP Sextetts. I thought the LP was more balanced frequency-wise than the MP and less rough sounding but more tinny. In my opinion, neither can compare to any of the other headphones I have ever bought.

 

[krmathis]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Quote: Originally Posted by vvanrij /img/forum/go_quote.gif Just a quick topic disturber (9020 posts ), what is so 'special' about these ortho headphones? Are they good just because of price<>quality, or are they also able to stack up to the likes of K1000/007/LNS/GS1000/RS1/ED9 etc.? First, I wouldn't put anything up against the K1000 that didn't look like it, and no ortho I know of is even in the same genus. Second, you're right about the price/quality ratio, though this is becoming less of an advantage every day unless you're a good DIYer and want to use the SFI drivers that are still available NOS. You know, I think most of the thrill is in awakening these headphones from a 30-year sleep and finding that they'll go up against some stiff modern competition with no more than a disc of felt added. Then you start asking yourself how many other products missed being great for want of a small disc of felt and the fun really begins.

That was very useful!

Cause I have seen this thread as well, but did not get inspiration to read all the 9000+ posts. This one sums it all up nicely...

 

[malldian]

Quote:

Originally Posted by mypasswordis /img/forum/go_quote.gif I had and sold malldian my MP and LP Sextetts. I thought the LP was more balanced frequency-wise than the MP and less rough sounding but more tinny. In my opinion, neither can compare to any of the other headphones I have ever bought.

Haha that was you, I completely forgot. If I recall the LP came with the pleather pads and when I switched them they became better. I didn't find either of them to be very "fun" but I found them neutral and fairly enjoyable. I am surprised that you found either of them to be rough sounding. Not very detailed cans, I got bored of the relaxed presentation and moved on from them. I would still like to hear the EP one at some point though, most accounts have found them more fun sounding I believe.

 

[Rick]

for anyone who has yet to realize, the SFI's do not emit equal sound in both directions. One side is substantially better than the other. You want positive signal to go to the blank contact, and negative to go to the one with the red contact (assuming the front wave will be the side where there is no cutout in the metal casing).

I suddenly have the bass monsters that were my 32ohms drivers back in the form of my 120ohms .

 

[Rick]

Quote:

Originally Posted by Random Murderer /img/forum/go_quote.gif the thicker one is neg.

umm...there isnt a thicker one.....o wow i take it back

 

[ericj]

Quote:

Originally Posted by fsma /img/forum/go_quote.gif for anyone who has yet to realize, the SFI's do not emit equal sound in both directions. One side is substantially better than the other. You want positive signal to go to the blank contact, and negative to go to the one with the red contact (assuming the front wave will be the side where there is no cutout in the metal casing). I suddenly have the bass monsters that were my 32ohms drivers back in the form of my 120ohms .

Absolute phase shouldn't matter as long as both drivers are wired the same.

There's two layers of fabric on the front of the driver, but you can get out a razor blade or craft knife and cut it off. Which seems to improve treble, for me.