[smeggy]

Quote:

Originally Posted by ludoo /img/forum/go_quote.gif Which brings us again to the question of custom drivers. How hard would it be to replicate the Wharfedale's drivers?

I think the drivers would be quite easy to reproduce which is why I'm going to try to get the old engineering info. If I can find some more specifics we may well be able to fabricate a decent facsimile. The ribbon is basically the same stuff computer flexible ribbon cables are made of. An arc magnet assembly should be easy enough.

I think the flat square ribbon iso should be straightforward.. relatively

 

[mypasswordis]

Ooh, I didn't think computer ribbon cable could work. Making drivers sounds like fun.

ludoo, you can always try using a reflex dot so that you don't have to damp as much, and maybe preserve some of the really deep bass.

 

[ludoo]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif I think the flat square ribbon iso should be straightforward.. relatively

Oooohhhh great! I can't wait for the day we will be able ot make our own orthos.

Quote:

Originally Posted by mypasswordis /img/forum/go_quote.gif ludoo, you can always try using a reflex dot so that you don't have to damp as much, and maybe preserve some of the really deep bass.

I dislike of reflex dots on principle.

I think that the damping should be right without directly reflecting anything back. But the principle is the same as the one I and kabeer are using with the donut damping, so punching a hole in the blue felt (or swapping it for a donut, or increasing the density of the existing donut, which are all variations on the same principle) will raise the treble without decreasing bass in a similar but less blunt way as a reflex dot. I'm still trying to decide on what exact tuning I want for the T20, but I will probably end up doing just that.

 

[ludoo]

On a side note, last night while chatting with kabeer we might have solved the mistery of the disappearing bass in my YH100: the thin cups and large drivers force the air to move out through the vents, which are damped by the large strips of thick felt. So even if there's little behind the driver (a disc of moorbrook, the stock foam, and some more moorbrook to damp the back of the cups), the vents damping is actually working as the primary damping material. My next step will thus be to remove the moorbrook behind the driver, and if they still sound overdamped tune the damping by trimming the vents felt. I think this mod is very effective at taming the YH100 (right know it tames them too well), will let you hopefully know tonight or tomorrow.

 

[bjarnetv]

good to hear that you are enjoying them warfers smeggy, seems like wharfedale understood the mysterious technology quite a lot better than yamaha and fostex.
lets hope some old engineer shows up, so that we can start making some more drivers

i got a pair of hp-50 from kabeer yesterday, but since my ef1 is stuck at the post-office i cant try them properly amped yet.
i did try them out of my beresford dac, but so far they sound very overdamped, with recessed midrange and overpowering highs. bass is quite nice actually; perfectly adequate for my tastes (i were told they were the bass light version)
looking forward to trying them on a proper amp, and i do expect them to transform into an acceptable headphone, but so far they are soundly crushed by the franken-sfi

 

[dBel84]

Quote:

Originally Posted by ludoo /img/forum/go_quote.gif On a side note, last night while chatting with kabeer we might have solved the mistery of the disappearing bass in my YH100

looking forward to your experience as I have tried a few variations and have the same experience as you - they are absolutely heavenly above 200Hz. I have even tried removing the vent damping to a thin layer of that fine dense felt but still NO luck.

..dB

 

[ludoo]

Quote:

Originally Posted by dBel84 /img/forum/go_quote.gif looking forward to your experience as I have tried a few variations and have the same experience as you - they are absolutely heavenly above 200Hz. I have even tried removing the vent damping to a thin layer of that fine dense felt but still NO luck.

I removed the only disc of felt behind the driver (there's still the foam and felt to damp the back of the earcup), and the situation improved considerably. They might still be on the bright side, but bass is there and full of body. Need more listening time, but they are sounding good.

It's puzzling that they manage to be damped without any felt directly behind the driver.

 

[dBel84]

I think I have been trying too many layers myself - I had a close look at the earcups and they are not clamping right down and I suspect I am getting more air leak than damping - I will try and simplify things up inside and see where that takes things.

..dB

 

[mypasswordis]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Yes, I'm sure the T40v1 would have its missing bottom octave restored with different earpads. No doubt about it. EQ does bring up the bottom, so it's not entirely gone, but the lowest lows are still weak with a simple tone control. A parametric seems called for. Or... new earpads. I do admire Smeggy's growing skill at quick-fabricating earpads..

I forgot to respond to this. Well, I was referring to my (friend's).. unfortunate mishap with one of my pads. A hole in the pad can do no good to the bass, since seal is nonexistent. I was also wondering, though... since the T20v2 and T40v1 probably have the same drivers, and though the T20v2 is supraaural with the drivers sitting right next to the ears, do you think the T20v2 pads could be acting as some kind of bass lens? And do you think some sort of lens could be implemented with the T40?

 

[wualta]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif I'm not overly fussed about the deepest notes, as much as I like them. The Wharfeys sound excellent even though they start rolling off at about 50Hz, much like the K1000 (they are more similar than I like to admit with a little tweaking). ..They have nice bass if a little light, deep but lacking some power there. ..They don't play very loud before distorting in the bass and they need an absolute buttload of power to drive. They are harder to drive than any other orthos, the K340 or the K1000. My floorstanding speakers are easier to drive.

I selected these passages from Smeggy's Wharfencomium to make an important point later on in this post, not to magnify the Wharfey's shortcomings. The advantage of the ribbon is that excursion is not a problem. The disadvantage is that sealing out backwave is a problem. But make the diaphragm big enough and get it close to the ear and bass will be adequate or better, as setmenu has found.


Quote:

Originally Posted by smeggy I'm going to see if there's any manufacturing drawings or parts specifications available in their archives. I doubt anyone from that era still works there but hopefully somebody kept records.

They've changed hands a few times, so this may be a vain hope, but I surely hope not. Some old guy living in a cottage in the Cotswolds.. I can see it now.. he goes to look for the papers and finds they've been eaten by a goat. Let's hope these shadows of my imagination are altered by the future. Good luck, Smeggy!


Quote:

Originally Posted by ludoo /img/forum/go_quote.gif I dislike of reflex dots on principle... But the principle is the same as the one I and kabeer are using with the donut damping..

Well... no, it isn't. Otherwise felt by itself would be regularly bringing up that top octave, but it doesn't. Felt soaks up treble, though it does reflect some.

I do sympathize with your feelings about the use of dots, which I called cheating when I introduced the idea. It is. If it didn't work so well, I wouldn't use it myself... ..on principle!


Quote:

Originally Posted by bjarnetv /img/forum/go_quote.gif seems like wharfedale understood the mysterious technology quite a lot better than yamaha and fostex.

No one exceeds me in my admiration for what the Wharfedalers achieved in the original Isodynamic (aka ID-1), but their design shows that they made some canny tradeoffs (see the selections from Smeggy's post, above), namely efficiency, flux uniformity and low bass, just as Yamaha did. It's just that in the case of the 'Dales, they were pure engineering tradeoffs rather than economic/marketing ones, or, in the case of the PMB 100, design-philosophy ones. What gives the 'Dales the spark of genius is that they did all this using the simplest possible design requiring the absolute minimum of precision manufacture, selling for no more than the typical good dynamic headphone of the time. They damped it well, and even though the enclosure wasn't the best, it's user-removeable!

And yes, if there's any hope that we could make our own ribbon headphones, the Wharfedale blueprint would be the starting point. I just wish there were a lot more ID-1s available.



Quote:

Originally Posted by bjarnetv looking forward to trying them [HP-50] on a proper amp, and i do expect them to transform into an acceptable headphone, but so far they are soundly crushed by the franken-sfi

If you're hearing bass from the 50 but the SFI sounds much better, something's not right. Report back on this one when your amp shows up, okay?



Quote:

Originally Posted by ludoo /img/forum/go_quote.gif It's puzzling that they [YH-100] manage to be damped without any felt directly behind the driver.

They are being slightly damped, but I think what's mostly happening is the natural frequency of the diaphragm is being moved up by the near-sealing of the vents. Air is elastic enough that damping by remoting the felt introduces an additional spring that reacts with diaphragm tension/compliance. Go a little easier on the vent felt and you'll be ready to damp the usual way. Or maybe you'll discover a happy medium with no damping but vent felt that's dense enough to bring the frequency response of the headphone in line with your tastes. I look forward to your results.

 

[wualta]

Quote:

Originally Posted by mypasswordis /img/forum/go_quote.gif since the T20v2 and T40v1 probably have the same drivers, and though the T20v2 is supraaural with the drivers sitting right next to the ears, do you think the T20v2 pads could be acting as some kind of bass lens? And do you think some sort of lens could be implemented with the T40?

I've never tested them outside of their pads to see if they're actually the same, but I've long assumed the T20 and T40 drivers of the '86--'06 era were different, since my T40 isn't anywhere near as loud as my T20. But I might have a new T20 and an old T40, and maybe Fostex gave the driver a magnet upgrade at some point. Who knows? All I can say is mine are different, and the way they respond to damping is very different.

The T40 came with a "lens", something that looks like it was supposed to hold the bass in, keep the pressure from dissipating as it entered a suddenly-larger volume-- the foam rings. Trouble is, they messed up the midrange, so I took them out. Maybe a different kind of foam in a different shape would actually do the job. Or maybe an earpad shape could be found that would contain the bass. Foam's easier to manipulate than earpad shape, so I'd start there.

It's also possible Fostex used those rings to shape the midrange to get that "pro audio" sound, which the stock T40 certainly has. I don't know for sure.

Fwiw, I did swap T20 and T40 earpads and didn't like the results.

 

[ludoo]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Well... no, it isn't. Otherwise felt by itself would be regularly bringing up that top octave, but it doesn't. Felt soaks up treble, though it does reflect some.

Well ok, you made a point. Reflecting and overdamping are not the same thing, or not enough. But the method of tuning we have been using is very effective, increasing treble without killing off too much (if any) bass, and I much prefer it to reflex dots. That was the real point I wanted to make.

As for the YH100, they are already very good and in certain ways much better than any other orthos I have heard, namely in soundstage, placement, details and a very realistic treble. They are now at last sounding like the big brothers of my bass-heavy HP-3. More later after a few hours of use.

 

[wualta]

Glad to hear the YH-100 is working out for you. I know it's been a bit of a struggle, and I can certainly appreciate the struggle.

I also wanted to make sure you understood that I have a "whatever works" philosophy and that even beyond that, I want to encourage people to try anything that they can think of to try, because that's how discoveries are made. If I don't think something will work, or if I disagree with an explanation, I'll say why I think that, but I won't discourage anyone from trying it, and I won't argue with anyone if they say they hear an improvement, especially if it's something I haven't tried for myself.

And if someone says that they don't like my ideas or techniques or explanations, I simply invite them to come up with something that works better.

 

[ludoo]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Glad to hear the YH-100 is working out for you. I know it's been a bit of a struggle, and I can certainly appreciate the struggle.

They have been that. Their design makes them awfully hard to damp, but the drivers are worth it.

Quote:

I also wanted to make sure you understood that I have a "whatever works" philosophy and that even beyond that, I want to encourage people to try anything that they can think of to try, because that's how discoveries are made. If I don't think something will work, or if I disagree with an explanation, I'll say why I think that, but I won't discourage anyone from trying it, and I won't argue with anyone if they say they hear an improvement, especially if it's something I haven't tried for myself. And if someone says that they don't like my ideas or techniques or explanations, I simply invite them to come up with something that works better.

Oh, I know. This thread is your lovechild and owes everything to you and your original adepts, and everything I have learned these months stems directly from your observations. Even something that I don't like too much like reflect dots is precious, as it makes me mull over new concepts and sometimes understand something I did not know before. And possibly come out with a tweak, or my own way of doing things as I'm stubborn and affected by a serious case of the NIH syndrome.

 

[smeggy]

The ID-1 is indeed a very clever design and I'm also full of admiration that they accomplished what they did for so little money and very primitive materials. The ribbon itself is thick and stiff with few traces, the assembly is just plain old well engineered. They looked at the whole thing as a task that needed creative and sound thinking.

The bass on them is very nice and sounds well balanced. The ribbon has the ability to produce good quantities of bass in free air like the K1000 because it's a long throw driver. You could easily use it as an 'off ear' driver with no pads.

You can't hard damp these like you can a stronger sealed ortho as the sound totally collapses due to stiff ribbon, low power and lack of internal sealing. Any mechanical damping will easily overpower their motor function. They're designed as a free air driver with no real damping at all. The stuff they put in the cups is simply to cut down reflections and keep dust and debris out. Held up to the light you can see clear through it, even though it's nearly 1/4" thick it's a very loose fiber structure.

I guess this is why my initial damping and pad configurations failed so resoundingly. You can't damp them and you can't have a small driver-ear volume as you end up with air coupling, which again will prevent them working properly. Big-ish driver, flapping freely and lots of air around them is how they were designed to work. You can't do anything to them without adversly affecting their function. They work and work well as they were intended.