[vvs_75]

Thanks! I know that they are completely different but I like to destroy things!

And if there a sign for improvement it's worth the shot. I think I need to transfer them to the Proline 750 first! : evil:

 

[kwkarth]

Quote:

Originally Posted by vvs_75 /img/forum/go_quote.gif Thanks! I know that they are completely different but I like to destroy things! And if there a sign for improvement it's worth the shot. I think I need to transfer them to the Proline 750 first! : evil:

These modifications should not be applied helter-skelter. I am not kidding you, you could ruin your headphones with these mods. I would strongly suggest you wait to modify your 2500s until I get a chance to examine and listen to a pair of 2500s to determine if anything can be or needs to be done to improve them.

 

[1Time]

kwkarth,

Where are good places to find the mod materials you used other than the Dynamat? Thanks

 

[kwkarth]

Quote:

Originally Posted by 1Time /img/forum/go_quote.gif kwkarth, Where are good places to find the mod materials you used other than the Dynamat? Thanks

I purchased all of the other materials at local fabric stores.

 

[kwkarth]

Quote:

Originally Posted by kwkarth /img/forum/go_quote.gif One final mod and they now require no additional EQ at all. They sound their best when everything is set to flat. I cut another 7cm circle of the fabric backed foam and placed it under the earpad mesh, so it covers all of the baffleboard.

Here are pictures of the final modifications. I consider the mods complete and the sound very impressive.

Here you can see the additional Dynamat applied to the outside of the baffleboard.

Here you can see I'm getting ready to apply the 7cm circle of foam backed fabric to the front of the baffleboard.

Here, you can see the foam/fabric circle overlaid on top of the baffleboard, ready for re-installation of the ear pad.

Here is a picture of the fabric/foam in place as it will be oriented once the ear pads are re-installed.

 

[Thurston Moore]

kwkarth/
I have now ordered my Proline 650s and I´m really curious about doing your mod suggestions, though I´m not totally confident doing it since I´ve never done any kind of mods before. I have some questions about your last mod that I´ve been wondering about:

- How come you chose to put the small piece of Dynamat on the front side of the baffle and not on the back side?

- In what way does putting fabric/foam on top of the baffle alter the sound? To me it seems like it could be a potential for making it sound muffled/veiled.

 

[kwkarth]

Quote:

Originally Posted by Thurston Moore /img/forum/go_quote.gif kwkarth/ I have now ordered my Proline 650s and I´m really curious about doing your mod suggestions, though I´m not totally confident doing it since I´ve never done any kind of mods before. I have some questions about your last mod that I´ve been wondering about: - How come you chose to put the small piece of Dynamat on the front side of the baffle and not on the back side? - In what way does putting fabric/foam on top of the baffle alter the sound? To me it seems like it could be a potential for making it sound muffled/veiled.

Very good questions!
I chose to put the dynamat on the front of the baffleboard for two reasons.
1. So I didn't have to open them up again. (laziness)
2. It presented less alteration to the internal volume of the headphone. If the volume is made too small, it could negatively affect the quality of the sound. I suspect the actual internal volume of the cavity was not critically or carefully calculated by Ultrasone since they didn't bother to control internal reflections either, however, adding the internal "stuffing" that I added, made the internal volume 1.2 - 1.4 times bigger in terms of the acoustic impedance that the driver sees anyway, so the main reason came down to not needing to open the cans again.

Putting the fabric/foam layer on top of the baffle does indeed alter the sound. To my ear it better controls the reflections between the listener's ear and the baffle board, thus lowering distortions further, and it does slightly attenuate high frequencies. To my ear, this reduction is right on the borderline between "just right" and a little too much. Without the foam, besides the distortions from reflections, there is still a little too much high frequency energy for perfect balance. I may punch a couple little holes in the material right on top of the driver to allow more high frequencies through, but I'm not sure yet, that it is needed. I originally had intended to cut a hole in the foam/fabric the same size as the driver itself so as not to impede any highs, but when I listened to them before I cut the holes, I decided to leave them as is for the time being. The highs are all there, but they're more polite and controlled, much like the Sennheiser HD600.

 

[kwkarth]

I have a pair of PL2500 ordered and on the way. I'm curious to compare them, sound and construction wise to the PL650.

They look, from pictures, like they're constructed from the same plastic mold, with the exception that the 2500's are open and the 650's closed. This appeared to be accomplished by a sonically welded plastic ring covering the vent holes on the inside of the 650 and a cosmetic plastic film on the outside covering the same vent holes.

The drivers differ as well. The 650 uses the 40mm gold sputtered mylar and the 2500, the 40mm titanium sputtered mylar. The voice coil is 75 ohms on the 650s and the VC on the 2500's is 40 ohms. This should be interesting.

Many of you are familiar with Sony's famous MDR-7506/MDR-V6 headphones. They use a mylar diaphragm driver. For a year or two, they produced an MDR-V7 model which was more expensive than the V6. The primary difference was that the V7 used a gold sputtered mylar diaphragm, otherwise identical to the drivers used in the V6/7506. They sounded a little brighter, but cleaner, as I recall.

I would expect that gold sputtering, would help suppress modal resonances on the diaphragm, if it had any effect at all, but not make it quicker. The actual mass of the gold is probably less than that of the air being moved, so maybe it made no practical difference in the mass of the diaphragm.

I would expect titanium to be resonant just like a titanium bicycle. So intuitively, the drivers would be expected to sound more ringy/worse than the gold sputtered ones. But, who knows... Maybe the titanium sputtering is actually effective in stiffening the diaphragm, making it a better piston.

Are there any mechanical engineers out there who could lend some intelligence to this wild speculation?

 

[vvs_75]

Quote:

Originally Posted by kwkarth /img/forum/go_quote.gif These modifications should not be applied helter-skelter. I am not kidding you, you could ruin your headphones with these mods. I would strongly suggest you wait to modify your 2500s until I get a chance to examine and listen to a pair of 2500s to determine if anything can be or needs to be done to improve them.

Thank for the warning! Since you got the Proline 2500 I will wait and see what you are going to do with them

.

But I try to trade them for PL750 since closed PH more convinient for me at this point!

Just curious why you went for the PL 2500 and not PL750?

As for the drivers the PL750,PL2500 and Edt. 9 share the same driver and according to Ultrasone :

"Providing this great sound for our Edition 9 is our finest quality 40mm titanium-plated Mylar driver. With its sought-after properties of high rigidity and low weight, titanium makes an ideal material for precision headphone drivers. The low weight of titanium allows the driver to move faster by comparison and therefore reproduce high frequencies with greater accuracy. This light weight also provides a better transient response which is important for fast-occurring sounds like snare drum hits and horn stabs. Overall the titanium driver provides greater detail and resolution for the discerning listener."


Not much of a help but just in case you didn't read it.

 

[kwkarth]

Quote:

Originally Posted by vvs_75 /img/forum/go_quote.gif Thank for the warning! Since you got the Proline 2500 I will wait and see what you are going to do with them . But I try to trade them for PL750 since closed PH more convinient for me at this point! Just curious why you went for the PL 2500 and not PL750? As for the drivers the PL750,PL2500 and Edt. 9 share the same driver and according to Ultrasone : "Providing this great sound for our Edition 9 is our finest quality 40mm titanium-plated Mylar driver. With its sought-after properties of high rigidity and low weight, titanium makes an ideal material for precision headphone drivers. The low weight of titanium allows the driver to move faster by comparison and therefore reproduce high frequencies with greater accuracy. This light weight also provides a better transient response which is important for fast-occurring sounds like snare drum hits and horn stabs. Overall the titanium driver provides greater detail and resolution for the discerning listener."

I went for the 2500 since it looks to me like it is simply an open version of the 750. If my surmising is correct, I can easily and non destructively make a 2500 into a 750, but I can't non-destructively make a 750 into a 2500.
Plus, I was able to buy a "B" stock unit for less than list price because it was "B" stock.

 

[vvs_75]

I just found out that the 750 and 2500 have different pads as well. Construction on the PL750 pads is better, which makes difference in sound too.

 

[kwkarth]

Quote:

Originally Posted by vvs_75 /img/forum/go_quote.gif I just found out that the 750 and 2500 have different pads as well. Construction on the PL750 pads is better, which makes difference in sound too.

How do the pads differ?

 

[vvs_75]

Quote:

Originally Posted by kwkarth /img/forum/go_quote.gif How do the pads differ?

This is part of the PM from another headfier who have and moded his PL 750:

"but youd want to buy the velour pads for the proline 750, as they differ greatly. the 750 pads have a solid vinyl inside lining, and the 2500's have a screened inside lining. (pads make a world of difference)"

 

[kwkarth]

Quote:

Originally Posted by vvs_75 /img/forum/go_quote.gif This is part of the PM from another headfier who have and moded his PL 750: "but youd want to buy the velour pads for the proline 750, as they differ greatly. the 750 pads have a solid vinyl inside lining, and the 2500's have a screened inside lining. (pads make a world of difference)"

That makes sense, one is designed for an open air headphone, one is designed for a closed can.
BTW, this does not make one pad "better" than the other, they're simply designed for different applications.

 

[Contrastique]

Nice Kwkarth! You are on the modding way haha! I hope you get to like them and I look forward to your impressions when compared to the 650 you modded. Maybe I read over it but are you first going to burn them in completely and see what they are capable of without the mod or start modding when you get them? Anyways, NICE!!!