Just listened to some Fostex T50RPs today... WOW! - Page 242

Copy that loud and clear!

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Originally Posted by SLaRe 

Keep tweaking them, killing the resonances and the stationary waves. When that job is done, they will go down to 15Hz, with a perfect defined and tight bass that doesn't bleed into the lower mids, like having a perfectly build 2.1 system straight to your head. We should treat these headphones as if they were speakers to get the best out of them.

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But your brain doesn't know what's leaking out of the cups unless it's reflected back, and unless you're wearing grados and sitting inside a narrow hallway, you're not going to be getting much of anything making it back to your ears to give you SS cues. Like I said, if the sound escapes from the cups, it's the same as being absorbed by material in the cups.

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Exactly what LFF said. When the audio is recorded, it has all the echos and reflections from the original stage/hall/studio where it was recorded. Any reflections inside the cups are going to decrease the sound stage because you can hear reflections coming off of the back of the cups. What has the best soundstage? Monitors in an anechoic chamber would be my guess, and that's what you're going for with all the damping. You don't want to hear the cups, you want to hear whats coming out of the drivers (provided they're relatively accurate).

Quote:

Originally Posted by arnaud 

 

 

Ok, to stop the polemic, I will take a shot at guessing your mod LFF based on your comment above. So, per your saying the treatment is unique, it implies it can't be based on some porous material, be it open cell foam or fiber based. It can't be an open rear chamber with some kind of resistive grill (you couldn't possibly manufacturing a grill ala Sennheiser HD800 anyhow ;). It can't be adding some ribs to kill some structural resonances, nor can it be apply free or constrained layer damping on the baffle plate and enclosure in general. Man, there's been quite a bit of stuff done for speaker design so it's hard to imagine!

 

But! ... Considering you have probably spent some time in recording studios given your hobby of mastering, I would guess you got inspired by acoustic diffusers. So, my guess is that you're basically cutting pieces of wood in various shapes and gluing them to the wall of the earcup in order to breakup some nasty resonances (and get some bit of additional absorption through scattering of sound waves).

 

If I guess completely wrong, at least you ought to confirm your treatment is none of the kinds I listed above. Being an acoustic engineer, I have seen my share of acoustic and structural treatments so I am intrigued by your post LFF!

Quote:

Originally Posted by LFF 

Wow...I'm seriously impressed. Your guess is wrong but your thinking along the right lines and the proposed ideas are something I do want to try. Dogears and I were having this same conversation last night and I encouraged him to try some diffuser ideas I had. Great job Arnaud! 

 

What precisely qualifies as acoustic diffusion?

Are the different Grado pads, the way they are shaped, and the combination of foams used in their construction a form of acoustic diffusion...is going from the stock pad on the T50 to the 02 pads a form of acoustic diffusion?

What about the white felt on the driver is that a form of acoustic diffusion?

In the T50, is acoustic diffusion needed on both the driver side and the ear side, or is one more important than the other?

You're still using the stock pads so I'm guessing it's more imprtant to do some sort of diffusion on the driver side but that doesnt mean you didnt, so something like Mr. Speakers use of paxmate on the ear side, not necessarily a dampening material like paxmate. Although could dampening be considered a form of acoustic diffusion?

Originally Posted by Psilocybe 

But your brain doesn't know what's leaking out of the cups unless it's reflected back, and unless you're wearing grados and sitting inside a narrow hallway, you're not going to be getting much of anything making it back to your ears to give you SS cues. Like I said, if the sound escapes from the cups, it's the same as being absorbed by material in the cups.

The brain measures the delay between the two ears in order to geolocalize sound. I rest my case that you need leaky cups in order to get a natural sounding non-muffled 3D SS. And if we were in the science forum, I would come back w/ some googley links proving my point, but I don't mean to threadcrap the T50RP R&D thread.

But that's only one part of the story, the way the engineer balanced/mixed every instrument was directly dependent on the angle of his monitors towards his skull, the size of the room, the foam on the cabin walls, the shape of his pinna, etc etc. You want the cups to somehow recreate the effect of walls in a room. Listen to LT1363, this opamp is amazing in how it lets you hear the walls reflections loud and clear...movies become as true to life as can get when using a semi-closed phone!

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Originally Posted by leeperry 

 

The brain measures the delay between the two ears in order to geolocalize sound. I rest my case that you need leaky cups in order to get a natural sounding non-muffled 3D SS. And if we were in the science forum, I would come back w/ some googley links proving my point, but I don't mean to threadcrap the T50RP R&D thread.

 

The stage these throw is quite large and more lifelike than my JH16 or my HD650, and feels close to the LCD-2, but I keep enjoying the music so much I honestly haven't bothered to go "which is better at THIS" and really dig into soundstage.  To me, if the sound and music are so detailed and immersive it's just not a worry.  Is it the biggest in the world?  Who knows.  Probably not.  If that's your thing, then so be it and I'm sure there's a solution out there somewhere.

Binaural recording isn't very common, but it is an attempt to address this issue by embedding microphones in a dummy head, thereby actually capturing the phase cues in the recording.  It works well, but you have to plan that the music will only sound right on phones, so nobody uses it except for the odd demo disc or project like Chesky's. 

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Yes, exactly, but you can't hear sound leaking out of the cups since it's leaking out and getting absorbed by the room. since headphones are designed for personal listening, very little of the sound is going to reflect and get back into your ears.

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That sounds reasonable, but it wouldn't give you spacialization, only coloration. SS is predominately the phase and amplitude difference between mics. However, you and I might be thinking two different things when we talk about SS. I can see how the cups would definitely impact the subjective "out of head" feeling (since you can feel this even with mono recordings, I guess it's more a function of setup than recording?) I guess my point was that you should be able to get a dramatic and open presence in closed cans just as well as open if designed correctly.

Originally Posted by mrspeakers 

Is it the biggest in the world?  Who knows.  Probably not.  If that's your thing, then so be it and I'm sure there's a solution out there somewhere.

Well, the nice thing about the cd3k is that it will throw sound behind your head, as explained in this link: http://www.headphonereviews.org/headphone/Sony/MDR-CD3000

"The highlight of the CD3000 is most certainly its cavernous soundstage that separates instruments into their own locations better than all but only the very best headphones. The first time I heard these cans, I was mesmerized by the expansiveness and surrounding nature of the soundstage. The angled drivers undoubtedly help these cans project a frontal soundstage better than many competitors. The drawback of the soundstage is almost a philosophical one, in that the CD3000 makes virtually any recording sound expansive and airy, which while very interesting and entertaining, is hardly transparent or natural. It is great for giving live rock albums that stadium ambiance and feel."

I find the T50RP w/ the side vents open to also send the SS extremes behind my head, but then I have to use crossfeed for music and inverted phase for movies rear channels otherwise I end up w/ a huge hole right in the center...IME all the dynamics I tried had a very loud center channel, prolly too loud actually.

A friend of mine who's an ortho modder doesn't like the "behind the head" feeling and planned on making vertical slits at the front of the cups, so the SS extremes would end right at his ears, and not behind....but as usual w/ irreversible mods, it's quite a gamble and I think he gave up.

All I know is that when my cat is lying on me while I'm watching a movie, sometimes an explosion or a loud noise would wakes her up...and I really don't listen loud. There definitely is some leaking going on, and I guess the human brain is more sensitive that you would be led to believe.

w/ binaural yes, as the whole room ambience has been captured...not quite the case w/ regular stereo recordings meant for speakers use, that need walls reflections in order to beef up their original SS. Create a thread in the science forum if you wanna keep on discussing about this if you like

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Originally Posted by mrspeakers 


Diffusion is essentially scattering the sound waves random directions and trying to break up reflections so they are out of phase and a bit "randomized.". Its totally different from absorbtion, and is often used in acoustic design of studios, movie theaters, concert halls, etc. I plan to put some in my home theater some day...
Due to the wavelength involved I honestly think it is a waste of time in a headphone. Not enough space to introduce meaningful diffusion.

I'd like to have some in our living room. We have a wood flloor and it's an acoustical nightmare. Anyway I'm asking because it seems this is the route LFF took and I'm guessing he's calling his mods, "paradox" because his mods are in contradiction or contavention to how people typically go about modding these things. I'm hopefully going to be getting mine back soon. I could go more toward your Rastapants, remove the white felt on the driverr and the felt on the earside and add some paxmate. I also have a pair of 02 pads on the Smeggy inspired Martypants that I just bought to tryout but, LFF seems to suggest that acoustic diffusion, not dampening is working in his headphone, thus the paradox?

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Lol, will do--I wish I had the testing equipment to do some real experimentation on this! :)

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Originally Posted by DaBomb77766 

So, my T50rps are apparently enroute to a local Long & McQuade store!

 

But I'm at a loss as to what I should do to them first.  There are just so freaking many mods, and the preferred mods appear to have changed over time.  What would be the currently recommended place to start?  And what materials would I need, and what would be the easiest way to get them in Canada?

/reiterates my question

This thread moves along fast!

Also, what properties are generally desirable in damping material?  Is it usually really light, open foam or really dense, more closed foam?

Quote:

Originally Posted by DaBomb77766 
 

Quote:

Originally Posted by DaBomb77766 

So, my T50rps are apparently enroute to a local Long & McQuade store!

 

But I'm at a loss as to what I should do to them first.  There are just so freaking many mods, and the preferred mods appear to have changed over time.  What would be the currently recommended place to start?  And what materials would I need, and what would be the easiest way to get them in Canada?

 

/reiterates my question

 

This thread moves along fast!

 

Also, what properties are generally desirable in damping material?  Is it usually really light, open foam or really dense, more closed foam?

I think the general consensus to eliminate the plasticky resonances is to dampen the baffle with blu tack, plasticine, or newplast. Some people have used dynamat but that stuff is sort of a pain in the ass IMO. A newer suggestion is tungsten putty but the consensus seems to be plasticine.

On the cup side the preferred method seems to be paxmate, but felt is a reasonable substitute, and several modders have used fiber fill or cotton too, as a dampener.