Orthodynamic Roundup - Page 1009

Quote:

Originally Posted by wualta 

The gold could be a tuning device. If you're having trouble getting consistent closely-matched tension levels, you could compensate by adding more or less mass to hit the same resonant frequency for each driver. Maybe that's easier than sweating the tension.

 

Now I thought about it, I think that's why the SFI drivers have problems balancing in the top end. They probably had bad manufacturing tolerance on the tension of the diaphragm, and probably different amount of mass of traces as well. (Looking at the diaphragms there is a variance in width of the traces.) Same thing happens with the HP-1 as well, albeit to a much lesser extend. Setting the tension of the diaphragm must be hard...
 

Quote:

Originally Posted by wualta 

an angry larval octopus.

you are correct.

^^ Could the highly tension T50rp drivers provide fostex an easier time when they do driver matching? Do you have any links to readings on the relationship between driver tension and frequency response? 

Because it is small, and feels the need to be angry in order to compensate for its smallness.

In search of better soundstage I have forsaken my previous dampening scheme & all of stock one as well. I removed everything including the tape on the grille. But then I was worried about dust getting inside driver so I stuck a thin tape over the magnet holes.

They now sound well balanced (slightly lesser bass) but more airy & spacious. They now actually ave a SS to speak of, not as big or 3d like DT880/ 600 but have a very satisfactory width and depth with more precise imaging.

Heard the Sansui SS-100 and the HE-5LE today with the Liquid Gold and Liquid Fire amps.

I do't know, the HE-5LE seems to have some weird coloration in the midrange and also the bottom end is lacking to my ears.

I wonder if they have really put any thought into damping by using starburst felts in the back and  in from of the driver. 

As for the SS-100, very nice sounding headphones. A tad unrefined in the midrange, a few peaks here and there in the upper mids and highs, very decent bottom end, good headstage, overall a very nice headphone and it was in excellent condition too. Nice score there for KwKarth.

Quote:

Originally Posted by wualta 

My SS-100's suspension bits are rather stiff too. And no, the early Fosteces all have round diaphragms. The square-diaphragm T50RP arrived early in 2002 and a few years later the entire Fostex RP headphone line went square. However, the simple voicecoil pattern of the T50v1 could easily have been adapted to a square or rectangular diaphragm, as with the Technics EAH-820 and 830.

Yeah, the voice coil layout is trivial and can be done and redone in a few minutes.  There are many more non trivial issues that have to be dealt with though.

Just to be clear, I'm not saying the layout doesn't matter, I'm just saying that it is a trivial thing to change it or re-lay it out from scratch, assuming you've decided what strategy you're going to employ.

Quote:

Originally Posted by wualta 

Right. It's a bit of a puzzle to figure out why there are so few rectangular planar diaphragms, especially since the first ortho to market, the Wharfedale, used a rectangular diaphragm.

 

Sony didn't make an ortho (farz we know), but I wonder if a pentagonal shape would benefit a large-diaphragm ortho design.

It would depend upon how the diaphragm was tensioned.  I can't think of any inherent advantage to that shape really. 

You want to be able to prevent modal resonances.  Overall shape could either help or hinder that goal.

^^ After you mentioned that term I did a search on it, and this came up: http://www.youtube.com/watch?gl=CA&v=aHkAFSZmMk4

I've learn something new today. Thanks.

Quote:

Originally Posted by kwkarth 

It would depend upon how the diaphragm was tensioned.  I can't think of any inherent advantage to that shape really. 

You want to be able to prevent modal resonances.  Overall shape could either help or hinder that goal.

Do you know the phenomenon of resonance? The resonance will occur within small unit of headphone too when it has symmetrical plane. It will cause divisional vibration of diaphragm and produce uneven response at high frequencies. If diaphragm is formed in an irregular pentagon, it will produce flat extended high frequency response. This construction of irregular pentagon is also applied on back plate and dampproof membrane. Just paraphrasing Sony engineers.
 

sorry to interrupt discussion but i plan on purchasing the Fostex T50RP soon and read they can be modded into something called thunderpants? not right away but sounds very interesting. might consider it down the line. if do,do i ask someone here to mod'em and how much would it cost if i ever decided on it?

i feel like a dumb dumb now making another thread wasting bandwidth cause i didn't spot this thread earlier.

In my fantasy world the traces on the surface of orthodynamic driver break up the standing waves, this may not be reflected in reality. 

Quote:

Originally Posted by wualta 

Yup, the nodes or modes are standing waves on the diaphragm caused by reflections from the clamped edge. I wonder how Audeze is handling this on the LCD-2. Anyone know? On Fostex's T30, they greased the clamp with silicone grease.