[rhythmdevils]

So Wualta, continuing the discussion of the backwave leaving the back of the enclosure and traveling around the outside of the headphone and through/around the pads to cancel out the bass or parts of the "frontwave"--  With the open back grado cups, when I cover the opening at the end of the cups with my hands and make a seal thus creating a completely closed headphone, all lower frequencies get completely wiped out, not just bass but midbass, and lower midrange as well.  (I can't tell if it also slightly affects the higher frequencies, or if they are now just kind of naked without their lower frequency counterparts and this sound funny) If I even get my hand close to the cup's opening, these lower frequencies start to drop off.  If the backwave cancels out the bass by leaving the back of the cups, then why would covering this open back diminish the bass?  It seems like it must at least also work in another way.  It must also travel through the diaphragm?  Or interfere with the movement of the diaphragm?
 
Another interesting part of this is that with the T20v1 and grado cups, there are screw holes in the baffle that are now not being filled with screws, so they act as ports into the pad enclosure (frontwave).  I currently have them plugged with tak, but removing them has an interesting affect of improving soundstage/air and removing bass.  However, the loss of bass with even all three unplugged is not even close to the affect of covering the back of the cups.  I would think that if the backwave was coming around the headphone, ports like this that lead directly from the outside to the "frontwave" would have a drastic effect, or at least more so than blocking the backwave. 

 

[joelpearce]

Sooooooo, it's time for me to do a bit of planning.
 
In a week or two, I'm going to have REB's Wharfedale ID-2 drivers arriving (big thanks to REB), and I need some advice from the experts: what do I do with them?
 
The Zebras are always the ID-1 drivers, right?  Has anyone transplanted the ID-2s into a different enclosure successfully?
 
I'm looking forward to trying a transplant other than the SFI drivers (most of which end up sounding kind of the same to me)

 

[wualta]

Quote:

So Wualta, continuing the discussion of the backwave ....

Re your Grado experiment: If you seal off an open headphone, you not only add a big treble reflector behind the diaphragm (a treble boost can sound like bass going away), you also trap a small volume of air in there which acts to stiffen the diaphragm. You've tuned the diaphragm upward (away from the bass) and added treble. This is why SmeggiPucks™ (the cute little wooden cups for SFI drivers) have a tiny pressure relief orifice, or SmeggiHole™. If a diaphragm is tuned for closed, you'll mess it up if you open the cup [which would make a great bumper sticker], and the other way 'round. Fortunately we've learned enough to compensate (usually; not always) for these changes. The lesson is that you have to do something with the bass backwave. It's like a wild animal. You can't just seal it up in a cup and lock the door, unless the cup is hilariously large. Those pressure waves have to go somewhere. The lighter the diaphragm, the more susceptible it is to this back pressure. Or even front pressure: do you remember reading about the Stax Lambda break-the-earpad-seal-and-get-more-bass effect?
 
As for your T20v1 transplant, the same thing applies. Seal the cup and you get a big treble boost (speaking of the Lambda, this is where I noticed how powerful the effect of a reflecting surface behind the diaphragm can be, treblewise, and yes, treble does travel through the diaphragm to a surprising degree). The soundstage/bass tradeoff has been with us since the days of the HD-414. I still think one of the reasons Dr. Goerike of AKG dreamed up passive diaphragms was to get soundstage without sacrificing bass, and then we saw how eventually the passive diaphragms became simple damped ports in the baffle. We also saw how the Wharfedale's driver isn't completely sealed to its baffle. Adding some out-of-phase (aka "antiphase", not to be confused with uncle phase) signal to a normal stereo signal seems to fool the ear into thinking the sound is coming from points out in the room, away from the headphones themselves. A highly addictive effect! Which is why I like speakers that are either dipoles or have dipole tweeters, or are semi-omnidirectional (the Ohm Walsh series).
 
I hope this makes some sense and helps, however little. Audio can quickly become fiendishly complex, and sometimes you just have to scream like a little girl, or would like to.

 

[wualta]

Quote:

In a week or two, I'm going to have REB's Wharfedale ID-2 drivers arriving: what do I do with them? Has anyone transplanted the ID-2s into a different enclosure successfully?
 

Wow. I'll be very interested to see how this turns out. Your experts here are Don (dBel84) and Kabeer (Kabeer). As far as I know, they're the only ones who've dealt deeply with the ID-2, which for those unfamiliar is nothing like the original Wharfedale-- it's more like an old Fostex T50v0 / 1 / 2. Not too surprising, since Fostex licensed patents from Rank Wharfedale-Strathearn-Leak-Whatever.
 

 

[rhythmdevils]

You probably can't hear me from Michigan, but I am screaming like a little girl right now! 
 
Yes it is very complex.  I think I either need to dedicate myself to learning a lot more, or just be happy with making pretty shapes out of felt and putting them in pretty places

 

[wualta]

One of the oddest things about sound is the great range of wavelengths in the audible spectrum, As Kevin Karth pointed out a few posts back, bass wavelengths are huge, 40 feet long for low bass. This means that things like speakers and people are minuscule by comparison. It's as if they were invisible, not even there. Waves this big just bend around them and keep going. It's also why little woofers in little boxes have trouble making them-- they mostly just punch little holes in the air, trying. At the other end of the audible spectrum, we're dealing with wavelengths a half-inch long! These behave verrrrrrry differently, more like light. They go out in straight lines and reflect off stuff and get absorbed by things like air, and carpet and people. Somewhere in the midrange it's... something in between, as  you'd expect. As soon as an object shows up that's the same size as a wavelength of sound, the sound can "see" it and be reflected by it.
 
And it just gets more interesting from there.

 

[sachu]

So i rigged up waht is basically a passive pre using a PEC carbon potentiometer. 

Result is...the plinius blows the mark levinson away. The sheer power is fully brought to the forefront. 

I honestly wasn't ready for waht i am hearing. WHo the **** said one needs a sub with a pair of magnepans?!!..one just needs the right amp..synergy. The top end too which i felt was a little tilted in the ML isn't present with the plinius. There are some things that i feel aren't brought forward with the plinius however, mainly in the high frequencies. This could be tied to the passive pre . SO a pre would be interesting to see what it will do to the rig. 

 

okay..here are some money shots..
 



 
btw..this new zeland puppy gets warm..super warm..fast! 
 
All i can say is..this weekend is going to be spent mostly indoors

 

[ardgedee]

You've convinced me. When I can have a dedicated listening room, I'm going to fill it with felt-covered mannequins to absorb any undesired midrange frequencies.
 
More seriously, I've been spending this week comparing the (planar) HE-6 to the (non-planar) HD800. And learning. And taking notes. It's been an interesting exercise, comparing two top of the line cans like this, because if I was asked to judge purely on terms of sound quality, I'd probably guess that the HD800 was the orthodynamic, and the HE-6 wasn't. The Sennheisers have the soundstage and location and detailed mids and highs, while the HE-6 has the bass and physicality. On the other hand, the HE-6 weighs approximately umpteen times as much than the HD800, so they betray themselves once I'm wearing 'em.
 
They're both very, very good...

 

[sachu]

Quote:

Quote:

In a week or two, I'm going to have REB's Wharfedale ID-2 drivers arriving: what do I do with them? Has anyone transplanted the ID-2s into a different enclosure successfully?
 

Wow. I'll be very interested to see how this turns out. Your experts here are Don (dBel84) and Kabeer (Kabeer). As far as I know, they're the only ones who've dealt deeply with the ID-2, which for those unfamiliar is nothing like the original Wharfedale-- it's more like an old Fostex T50v0 / 1 / 2. Not too surprising, since Fostex licensed patents from Rank Wharfedale-Strathearn-Leak-Whatever.
 

The solution for the ID2 is basically cutting the single big felt in half down the side so you end up with two pucks.
 
Then for the one up against the driver put a quarter sized hole in the middle so you end up with a puck (up against the cup ) and a donut against the driver.

 

[dBel84]

Is it just the drivers you are getting or is it the entire package? The Wharfedale ID2 has a single solid felt puck (not unlike a hockey puck) , the Leak has 2 pieces of felt  -  one thick and one thinner with the same overall thickness as the wharfedale. The best I could get was to make a donut of the thinner part of the Leak damping and and keep the thick pad underneath that. Problem with this driver is that it is very tightly suspended on the plastic frame - sounds like a snare drum when you tap the surface. I have thought of transplant but the headphone will be pretty big . The sound in stock housing is actually pretty good, has tight bass and is probably the fastest of the orthos I own. Pads might actually be all that the headphone needs  -  maybe time to try the O2 pads on them. 
 
I have been doing quite a bit of listening with my T20V1 lately - moderately damped with O2 pads, it is really superb, especially with my current set up ..dB
 
 
edit : [size=medium]Sachu, that set up just looks wicked. Trust you to wait until I left!! am guessing you might want the passive transformer coupled pre-amp from my parts bin ( was waiting for my zen amp ...... ) [/size]

 

[gurubhai]

Quote:

I have been doing quite a bit of listening with my T20V1 lately - moderately damped with O2 pads, it is really superb, especially with my current set up ..dB [size=medium]) [/size]

I really miss my T20v2 especially since I made my amplifier. Has anyone tried a TP style housing with these ?
 

 

[joelpearce]

The reason I'm getting them is that one of the cups on the original pair broke.  So yeah, it's going to need to go into some kind of new enclosure.
 
Hmm... this will be challenging and interesting.
 
Quote:

Is it just the drivers you are getting or is it the entire package? The Wharfedale ID2 has a single solid felt puck (not unlike a hockey puck) , the Leak has 2 pieces of felt  -  one thick and one thinner with the same overall thickness as the wharfedale. The best I could get was to make a donut of the thinner part of the Leak damping and and keep the thick pad underneath that. Problem with this driver is that it is very tightly suspended on the plastic frame - sounds like a snare drum when you tap the surface. I have thought of transplant but the headphone will be pretty big . The sound in stock housing is actually pretty good, has tight bass and is probably the fastest of the orthos I own. Pads might actually be all that the headphone needs  -  maybe time to try the O2 pads on them. 
 
I have been doing quite a bit of listening with my T20V1 lately - moderately damped with O2 pads, it is really superb, especially with my current set up ..dB
 
 
edit : [size=medium]Sachu, that set up just looks wicked. Trust you to wait until I left!! am guessing you might want the passive transformer coupled pre-amp from my parts bin ( was waiting for my zen amp ...... ) [/size]

 

[s002wjh]

how am i gonna get through 1000+ pages

 

[wualta]

 
Quote:

how am i gonna get through 1000+ pages

Fret not-- there's a dedicated search engine. Read the first 5 or so pages to see what it's all about, then pick some topics and seek 'em out.
 
Today is the birthday of the man who gave us that search engine, Ludovico Magnocavallo. I wished him a happy birthday, made a lame joke about auguri, and asked him to bang on the side of the search engine to make it self-update again.
 
Sachu's experience with the Magneplanars is instructive. What orthos need to make the little magnetic fields created by their diaphragms grow up big and strong is current, lots of it, and even more to the point, reserves of current. Amps with tiny power supply capacitors need not apply.

 

[DefectiveAudioComponent]

Each page is a joy to read. 1000+ pages of fun
 
Quote:

how am i gonna get through 1000+ pages