[nickchen]

I have actually EddieE's HP1 here (standard-modded), but it is a bit dull compared to the rich sounding T20, and there is hardly room for any more damping. The Wiki suggests a "treble reflex dot". Can someone explain how such a reflex dot can be implemented?

 

[rhythmdevils]

That was my problem with the Yamahas when I had the YH100.  By the time it was dampened enough those tiny cups were so full of felt it sounded like I was listening to headphones in outer space or inside a coffin or something.  Blah.  But I would like to try them again, and I would really like to try grado-ing them.  Does anyone have a Yammy around they don't need for a few weeks?  It would be nice to just try it instead of buying another headphone...  Or does anyone want to trade a Yammy for a T20v2?

 

[rhythmdevils]

Quote:

What you've got is fine. You are getting some reflection from that short tunnel, but feh, it's minor and not worth worrying about until you get everything else absolutely nailed down.
For what it's worth, I was thinking of a horn-type flare, not a cone.
As for the idea of bass needing containment and reflections, wouldn't the standard enclosure be perfect for that? The reason a no-cups situation sounds thin is because of the Backwave Is Powerful principle. Let it loose right near the earpads and unless the seal is perfect, you'll lose some bass, guaranteed. Lead it out the back through even a short tunnel to delay it and the problem starts to go away because the frontwave and backwave aren't in phase anymore. It's as if a proton and antiproton both arrived at the same spot but at slightly different times. No annihilation. Likewise, a vent needs a delaying element, like a little piece of felt, for the same reason-- to trip up the backwave. Make the baffle big and again, the backwave has to travel to arrive at the earpad, and it arrives too late to cancel out its counterpart, and in fact starts to provide some stereo enhancement, aka wider headstage. Such is the theory I've cobbled together from scraps and tatters and bits of Sennheiser brochures. Every time someone does a nifty transplant like yours or Smeggy's, this theory (more like an operating hypothesis) gets tested. So don't stop, keep trying different things.
 

 
Great post!  I seem to have gotten off course as far as planar theory with my obsession to make these sound right and opening them up over and over again.  I wish there was a way to extract all the information like this post out of this thread.  There's so much good content in here, but there's way too much, and mixed in with so much conversation it's impossible to find it in the 1000 pages here. 
 
You are saying that the backwave makes it's way to the pads through the driver, right?  I assume that's what you mean, at first I thought you meant going all the way around the outside of the enclosure, but that would delay it enough for it not to be an issue, and then there's the seal of the pads to keep it out. 
 
I don't know where to find a horn-flare cup.  I'll have to see if someone very skilled could make something like that.  Or if there is a plastic piece that could be re-purposed. 

 

[BoilermakerFan]

Quote:

Sweet..getting delivery of my magnepan 1.6s in an hour   Time for me to slowly bug out of the headphones world.

I have some sweet conceptual plans for a 70W/ch tube amp. 

 

[dBel84]

quick cheap power 
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-812
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-300
 
..dB

 

[Rick]

Quote:

That was my problem with the Yamahas when I had the YH100.  By the time it was dampened enough those tiny cups were so full of felt it sounded like I was listening to headphones in outer space or inside a coffin or something.  Blah.  But I would like to try them again, and I would really like to try grado-ing them.  Does anyone have a Yammy around they don't need for a few weeks?  It would be nice to just try it instead of buying another headphone...  Or does anyone want to trade a Yammy for a T20v2?

YGPM

 

[wualta]

Quote:

Originally Posted by ardgedee /img/forum/go_quote.gif
 
What really surprised me is Jude's AKG K340 hybrids. The bass was a little wooly (and that could be the amp's fault), but it complemented the mids and highs in a totally pleasing way, and the whole ensemble worked better on my system than I expected. It's a model I'll have to keep an eye out for.

There's lots of discussion of the K340 here on HF. Watch out for the numerous myths and misconceptions as you go.

 
Quote:

Oh, I thought the vintage T50 was practically non-existing?? **new perspectives** 
I'll start monitoring the buy&sell section more thoroughly then...

They're nearly impossible to find in the US. Germany might be a different game entirely. Good luck!
 

Quote:

Sweet..getting delivery of my magnepan 1.6s in an hour   Time for me to slowly bug out of the headphones world.

Nah. You'll be back.
 
 
Quote:

The Wiki suggests a "treble reflex dot". Can someone explain how such a reflex dot can be implemented?

It's one or more small reflective bits stuck to the back magnet of an ortho driver. Being small, it's a selective reflector of treble wavelengths. It's a tweak for the top ~2 octaves if you're suffering the Ortho Treble Droop problem. A piece of sticky tape will work.Adjust the size and you adjust the range of frequencies over which it's effective. There is no "correct" size for a given headphone/owner-- experimentation is necessary.

Quote:

Originally Posted by rhythmdevils /img/forum/go_quote.gif
 
You are saying that the backwave makes it's way to the pads through the driver, right?  I assume that's what you mean, at first I thought you meant going all the way around the outside of the enclosure, but that would delay it enough for it not to be an issue, and then there's the seal of the pads to keep it out. 
 
I don't know where to find a horn-flare cup.  I'll have to see if someone very skilled could make something like that.  Or if there is a plastic piece that could be re-purposed. 

No, not through the driver. The driver generates the backwave. If there is no cup (as in your example of thin sound), there is no delay and thus there is maximum chance of cancellation given the tiniest chink in the earpad's armor. The cup, or the cup-with-a-hole (your Gradoid "tunnels" are an example) acts to delay the backwave a bit. More would be better, but even a bit helps.
 
You don't need a horn-flare doodad, but one of our resident woodbutchering experts could easily make you such a thing when the time comes.

 
Quote:

quick cheap power 
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-812
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-300
 
..dB

Hey, that is quick and cheap. Can you ever have too much utility quick-cheap amp power? I submit that you cannot.
 

 

[rhythmdevils]

Really?  You think the backwave goes out the back of the driver, around the side, and gets through the pad to cancel out the opposite waveform that was generated inside the pad?  That is astonishing.  Pads are something to play with then not just because of the chamber they create, but because of the backwave they do or do not let in from the outside.  By that logic, it would be good to have very well insulated pads with orthos.  Maybe that is partly why the LCD2 and Thunderpants sound so good
 
This makes me think of so many more questions...

 

[JamesMcProgger]

newbie questions time!
 

• Does orthos needs to burn in just like regular drivers?
• Would a regular SFI planar driver in a deep cup without any damp sound flat?
• SFI planar drivers = orthos? or are any specific type of them?
•  
• Lastly: may a volume knob cause lost of quality (this i know is posible, for sure. but this next idk) or loss in the amount of volume? 

 
Thank you in advance!
 
(im trying to read all but this thread is too huge)

 

[Rick]

Quote:

newbie questions time!
 

• Does orthos needs to burn in just like regular drivers?
• Would a regular SFI planar driver in a deep cup without any damp sound flat?
• SFI planar drivers = orthos? or are any specific type of them?
•  
• Lastly: may a volume knob cause lost of quality (this i know is posible, for sure. but this next idk) or loss in the amount of volume? 

 
Thank you in advance!
 
(im trying to read all but this thread is too huge)

1. That is a controversial question. The answer is, if you believe there to be burn in periods on dynamic drivers, then there is no reason that you would think otherwise about ortho drivers.
 
2. No it would sound like *ahem* crap *ahem*. SFI's need to be quite heavily dampened.
 
3. The SFI's are orthodynamic dipole drivers. Ortho's are planars, so yes.
 
4. ??  you left 4 blank.....
 
5. A volume control is a means of putting resistors directly in the path of the audio signal. Naturally that is a big "no-no" (for the most part), so a poor quality volume control will add noise and distortion to the signal. This noise and distortion does not relate to the amount of volume.

 

[JamesMcProgger]

Quote:

Quote:

newbie questions time!
 

• Does orthos needs to burn in just like regular drivers?
• Would a regular SFI planar driver in a deep cup without any damp sound flat?
• SFI planar drivers = orthos? or are any specific type of them?
•  
• Lastly: may a volume knob cause lost of quality (this i know is posible, for sure. but this next idk) or loss in the amount of volume? 

 
Thank you in advance!
 
(im trying to read all but this thread is too huge)

1. That is a controversial question. The answer is, if you believe there to be burn in periods on dynamic drivers, then there is no reason that you would think otherwise about ortho drivers.
 
2. No it would sound like *ahem* crap *ahem*. SFI's need to be quite heavily dampened.
 
3. The SFI's are orthodynamic dipole drivers. Ortho's are planars, so yes.
 
4. ??  you left 4 blank.....
 
5. A volume control is a means of putting resistors directly in the path of the audio signal. Naturally that is a big "no-no" (for the most part), so a poor quality volume control will add noise and distortion to the signal. This noise and distortion does not relate to the amount of volume.

Thank you sir!
just what i wanted to know.
no wonder mines sound like ahemm *crap*.
 
 
and there is no 4.

 

[ericj]

Quote:

You are saying that the backwave makes it's way to the pads through the driver, right?  I assume that's what you mean, at first I thought you meant going all the way around the outside of the enclosure, but that would delay it enough for it not to be an issue, and then there's the seal of the pads to keep it out. 
 
I don't know where to find a horn-flare cup.  I'll have to see if someone very skilled could make something like that.  Or if there is a plastic piece that could be re-purposed. 

I think the consensus is that there is not, in fact, enough delay in the average earcup design to prevent the backwave from coming all the way around and canceling out the front wave. Unless you have a whole lot of bass, which we generally don't.
 
wrt horn-flare cups, I think wualta may be somewhat facetiously referring to making headphones out of something like a carburetor velocity stack.
 
I recently ordered a set of plastic watch movement holders that may do similar duty (if they are tall enough) but you'd have to buy two sets to get two the same size . . .
 
One of my other hobbies reared it's ugly head. disposable income and an interest in horology mix too well. watchmaker's tools are never exactly cheap, and there are so many of them required for relatively simple tasks.

 

[wualta]

Quote:

Really?  You think the backwave goes out the back of the driver, around the side, and gets through the pad to cancel out the opposite waveform that was generated inside the pad?  That is astonishing.  Pads are something to play with then not just because of the chamber they create, but because of the backwave they do or do not let in from the outside.  By that logic, it would be good to have very well insulated pads with orthos.  Maybe that is partly why the LCD2 and Thunderpants sound so good

Absotivlutely yes. One of the major discoveries of this thread: earpads can make or break a headphone.
A pad is a very important component in the total sound a headphone delivers to the ear. A pad thai is delicious, especially with some lime juice. Sorry, I was getting hungry. But yes, if there's no cup and the baffle is small, the backwave goes out the back of the driver and, as long as we're talking about the bass frequencies, it immediately curls around the entire headphone and bathes it in antibass. High frequencies stay in a beam, head straight out, and keep going. In such an extreme case, it would be entirely up to the earpads to block the antibass, and even the tiniest break in the seal will let some through. Bass can also pass through earpads that aren't sufficiently meaty, as we found with the T50RP. The Stax O2 pads are very meaty, which is one reason why they're the Thunderpants pad of choice.
 
When your head fills with questions, that's a very good sign.
 
 
 

 
Quote:

Originally Posted by ericj
 
I think the consensus is that there is not, in fact, enough delay in the average earcup design to prevent the backwave from coming all the way around and canceling out the front wave. Unless you have a whole lot of bass, which we generally don't.

 

wrt horn-flare cups, I think wualta may be somewhat facetiously referring to making headphones out of something like a carburetor velocity stack.

There's not a heckuva lot of delay in the average earcup, that's true. They'd have to be pretty big to solve the problem by sheer size alone. That's why there are damped vents in closed-vented cups, and why Grado uses the "tunnel" style semi-open-back cups plus what looks like felt inside.
 
Facetious about actually sticking velocity stacks on a headphone, but not really being facetious about the basic "horn" (more of a hornlet) back idea. It's what the Choco Donuts would have been if the mouth of the hornlet had been the same diameter as the driver. That way there's no way for backwave of any frequency of interest to be reflected back to the driver-- it would all just curve out and away, and there'd be maximum practical path length for the bass backwave to travel. But it's a refinement, not a fundamental necessity.

 

[rhythmdevils]

Quote:

Quote:

Really?  You think the backwave goes out the back of the driver, around the side, and gets through the pad to cancel out the opposite waveform that was generated inside the pad?  That is astonishing.  Pads are something to play with then not just because of the chamber they create, but because of the backwave they do or do not let in from the outside.  By that logic, it would be good to have very well insulated pads with orthos.  Maybe that is partly why the LCD2 and Thunderpants sound so good

Absotivlutely yes. One of the major discoveries of this thread: earpads can make or break a headphone.
A pad is a very important component in the total sound a headphone delivers to the ear. A pad thai is delicious, especially with some lime juice. Sorry, I was getting hungry. But yes, if there's no cup and the baffle is small, the backwave goes out the back of the driver and, as long as we're talking about the bass frequencies, it immediately curls around the entire headphone and bathes it in antibass. High frequencies stay in a beam, head straight out, and keep going. In such an extreme case, it would be entirely up to the earpads to block the antibass, and even the tiniest break in the seal will let some through. Bass can also pass through earpads that aren't sufficiently meaty, as we found with the T50RP. The Stax O2 pads are very meaty, which is one reason why they're the Thunderpants pad of choice.
 
When your head fills with questions, that's a very good sign.
 

Yes, definitely!  I knew that pads were very important because of my experiments swapping pads on AKG's and Grados, but I always thought it was just because of the pad material and enclosure volume and the way that affected the sound. 
 
I read the Choco donuts thread, I hadn't seen that one before it was full of some good information and ideas.  It would be cool if there was an ortho wiki for damping and "planar theory" or a way to highlite informative posts so that noobs could learn about all this stuff.  I might take a stab at reading this whole thread but I'm not sure how that's going to go....  Maybe I will start pasting useful bits I find into a document.  I'm sorry that you've had to repeat yourself, but I definitely appreciate it!  The more I learn, the more interesting it all gets. 
 
If the backwave comes around the outside of the headphone, has anyone tried external damping on the outside of the headphone to further slow it's journey?  The grado T20v1 would be perfect for this because of the way the baffle has a much bigger diameter than the cup.  Maybe i'll try applying felt or tak to the back of the baffle and see what happens. 
 
I wonder if I could get a huge mass of tak or putty or something to play with cup housing shapes before committing something to wood.  Would be a heavy headphone! 

 

[nickchen]

It is heavy like an anvil anyway!