[wualta]

Oh! Shoe holders on hangers for traveling, not holders for collapsible shoes. Now I get it. Now it all makes sense. Never heard of 'em.  B'srsly, is the back made of a porous nonwoven kinda... stuff that we can harvest and just possibly use? To the dollar store!

 

[ludoo]

Quote:

Hmm, I wonder how good lasers are at punching thousands of tiny holes of a predictable size in metal foil...?

Pretty good I guess, size of the laser beam for cuts is 0.01mm and you can supply your own material. What do you need it for?

 

[wualta]

A damping layer. I personally don't need it, but someone might. An experimenter might find it handy to have a set of discs with holes of varying size. Crimp the edge to form a shallow bowl and fill it with a rockwool or fiberglass disc and you have a damper module that will absorb treble and damp the driver too. Just a random thought.

 

[gurubhai]

Quote:

Oh-- I just saw Tyll Hertsens' latest blog entry wherein he and a bunch of hard-headed orthonauts are really bearing down on the Neo Ortho driver-variability problem and the related measurement-repeatability problem. Good reading.

What's your take on the variability issue?
We have seen considerable variability in vintage orthos too.Is it an issue of the technology itself or should we just blame it on manufacturer QC.
 
Other stuff : worked out a mod for LCD-2(working with friend who owns them) which involves paper diapers & rockwool. I like them much better now. The treble peak has been taken care of & the extension is improved.
The soundstage has also improved. On the whole, a lot more balanced sound now.
An interesting finding was that unless you cover the topmost & bottom rectangular openings with felt, the bass decreases substantially.Something like a bass-cancellation effect, wonder what's going on there?

 

[wualta]

We knew from the start when dealing with tensioned diaphragms that getting consistent tension and voice-coil mass in production would be the test that separates the mensch from the nebbish, companywise. The thinner the diaphragm material, the more trouble is likely to follow.
 
Yamaha did pretty well with their nontensioned diaphragms, at least in their TOTL models, but we saw how the BOTL models varied. Not that this is strictly an ortho problem! We saw how AKGs were all over the place, while the company stood by in frozen denial. Channel spectrum-matching has an easily audible effect on the sharpness or accuracy (not the width) of the stereo stage, so this is not a trivial or tweak-geek problem. Nor is perfect spectrum matching between channels in production an easy thing to achieve. Heck, it's not easy, period.
 
A premium headphone should obviously have individual testing and matching, but the ease with which this is done depends heavily on how much money the company can spend on machinery and floor space devoted to automated testing. To do it all by hand would be a giant hair-tearing PITA.
 
Glad to hear your LCD-2 mod is coming along. Why the bass should vary because of the [small] top and bottom openings of the grille, I have no idea. It certainly makes no obvious sense. Does this mean that if you had two bone-stock LCD-2s that sounded exactly alike and plugged part of the grille on one, that one would have more/better bass?
 
 

 

[gurubhai]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif
Why the bass should vary because of the [small] top and bottom openings of the grille, I have no idea. It certainly makes no obvious sense. Does this mean that if you had two bone-stock LCD-2s that sounded exactly alike and plugged part of the grille on one, that one would have more/better bass?
 
 

I was talking about openings of the driver(magnet) not of grille.
I listened to the LCD-2 without the grilles/stock felt & the bass actually decreased & became tighter.Doing the same thing on my other orthos leads to increased, uncontrolled mid-bass.
I then proceeded to one by one cover the magnet openings with the felt & noticed that the bass returned when top/bottom openings were sealed.
 
 

 

[vid]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif
 
Yamaha did pretty well with their nontensioned diaphragms, at least in their TOTL models, but we saw how the BOTL models varied. Not that this is strictly an ortho problem! We saw how AKGs were all over the place, while the company stood by in frozen denial. Channel spectrum-matching has an easily audible effect on the sharpness or accuracy (not the width) of the stereo stage, so this is not a trivial or tweak-geek problem. Nor is perfect spectrum matching between channels in production an easy thing to achieve. Heck, it's not easy, period.

 
Could you clarify the thing about AKG, i.e. that they denied their channel-matching problems? In what way did they deny it, and which time period are we talking, and what sort of problems did they have? I measured a mid-level AKG phone from the 80s, and they seemed to have an almost perfect match of channels. But I also measured a TOTL AKG phone from that era, and it was, to quote you, all over the place. So apparently they were able to do it right even back then, but just didn't want to most of the time.
 
(I also measured the channel balance on my HOK 80s, and that thing was way out there. But I think it's possibly due to my mods, too.)

 

[wualta]

I didn't say AKG's channels didn't match, because I don't know if they did or not. I was speaking generally about production consistency in the sentence you quoted. One headphone would be bass-lite, another would be bass-heavy, and some would be bass-normal. Check the forums on the 501 and 340 and Sextette. AKG claimed the changes they made had no effect on the sound.
 
Gurubhai, have you got photos?

 

[vid]

I see. I had the wrong context, my bad. (Wasn't attacking you there, just eager for knowledge.)

 

[wualta]

No attacks assumed. The K501 knockdown-dragout is nearly ancient history now, but the upshot was we had people vehemently defending the sacred honor of their headphones' makers when, it turned out, they didn't deserve it.

 

[rhythmdevils]

Sennheiser did the same thing, and in a very similar way.  They changed the material used in the vents in their HD650 and it changed the sound and they vehemently deny any such acoustic change. 
 
I wonder if the original engineers are behind such material changes.  It could be a more basic team, or even just one person who doesn't understand the complexities of things as well...

 

[Kabeer]

Deffo agree with wualta, im sure that in the modern dynamic word there are differences between pairs.
Its like guitars, even if you make them the same dimensions using a robot, theyll sound a bit different, buthave overall largely the same sound.

 

[wualta]

Anyway, it was a good lesson for us all: if somebody says they hear something out of the ordinary, we should give them the benefit of the doubt before casting aspersions on their amps/interconnects/maritalstatusoftheirparents.
 
RD brings up a good point. It doesn't take a lot of imagination to see accountants at work in the "decontenting" of certain PMB headphones over time, to pick just one example.

 

[rhythmdevils]

meh, your parents are divorced so whatev's

 

[leeperry]

BTW, anyone ever compared a vintage Stax such as the "Stax SR-X Mark-3" to the vintage Yamie's? Too bad its compatible transformers need to be plugged onto a speaker amp...
 
But this review sure sounds appealing: http://kenrockwell.com/audio/stax/sr-x-mark-3.htm