[runnin17]

Here is what Fitz Pm'd me about modding the Ultrasone PROline 2500 to level out the treble and mids to make them more balanced.

Quote:

To do everything: Take the earpads off by twisting them counterclockwise, and remove the screws that hold the metal baffle plates in place. Fill the earcup loosely (don't pack it in) with some kind of loose stuffing, whatever you can use will work. I used some stuffing out of a pillow, but you could probably just pull apart some cotton balls. As long as it's fairly even in consistency it'll be fine. Don't worry too much about the exact amount, you'll probably have to come back to it again anyways. More stuffing equals less bass, and less stuffing equals more bass, but with no stuffing the bass would be overwhelming after the other mods. Put the metal plates back on the earcups, making sure none of the stuffing is sticking out around the edge. Take some masking tape (so it leaves no residue if you ever remove it), and cover some or all of the smaller sized holes over the drive. Then take some craft felt that's about 1/16" thick, and cut two circles out of it just slightly smaller than the earpads. Put the felt over the metal plates and twist the earpads back on. Listen to them for a while and adjust the amount of stuffing to tune the bass up or down, and adjust the tape to tune the treble up or down. Make the adjustments gradually and after listening to several songs each time. -Fitz

And here are pics of me doing the mod.

Pic 1: Normal PROline 2500's (aren't they purrrrty)

Pic 2: Remove the ear pads to expose the metal baffles

Pic 3: Showing the four screws that hold the baffles on removed (take a good look at this picture and note that there are three screws that you don't want to remove)

Pic 4: Metal baffles removed (be careful with this step, you might have to use a small flat head screwdriver to GENTLY pry the baffles away from the plastic casing)

Pic 5: The cotton pieces I used for stuffing (you can use any type of stuffing, I just had this cotton lying around)

Pic 6: Casing with cotton in place (notice that you don't really need that much; as Fitz stated above, the more stuffing the less bass) With the amount of cotton that is in the pictures below the bass is still very present. Originally I had too much cotton and it really took the bass down to Senn HD580 levels.

Pic 7: Metal baffles screwed back on and tape put in place (take note that I used scotch tape b/c it was all I could find that wouldn't leave a residue); Fitz suggested to use masking tape and I probably will next time I remember to pick some up. I also put the tape over all the holes except the outer holes; I am experimenting with this to see what it does with the sound.

Pic 8: Close up pic of the tape over the driver holes

Pic 9: This is the felt that I used (not the best stuff, but it seems to work really well)

Pic 10: I was in a hurry and didn't cut my felt all that well. I will cut out some better pieces that fit better to see if it makes any differences.

Pic 11: Modding done!!!! It takes about 10 minutes if you are careful and it really does make a huge difference in the sound. THANKS FITZ!!!!!!

 

[mrarroyo]

You do not know how happy I am you started this thread. I say so because as you will see from the pictures below there has been a modification done to the PROline 2500 that I was not aware off. Perhaps others here will benefit and the modification would explain the differences in sound being reported.

I bought my Ultrasone PROline 2500 from fellow Head-Fier HiFlight in July of 2007. He had owned them for about 6 mohts, thus the pictures below are from a late 2006 production run of the PROline 2500.

You will see that the five(5) larger openings towards the top of the metal driver cover which are shown in runnin17's are missing from mine. Has Ultrasone done other modifications? If yes what would they be?

Note: Please click on the thumbnail below to see the full size pictures.

 

[mrarroyo]

I just sent Ultrasone USA a note asking for additional information. I wish others would see this post and discuss this issue.

 

[Fitz]

The one I worked on didn't have those five large circles either, Miguel. The venting on the back of the driver looks different than I remember too.

 

[jgonino]

Just a note, runnin17 is the third owner of those headphones. I am the second, with member 'liver' being the first.

Also, the black circles are not holes, that are small padded circles attached to the metal.

 

[runnin17]

The padded circles have adhesive on the back of them. Maybe 'liver' did some modding that no one knew about. Either way the phones sound really good now and if the padded circles are a modification I guess you can add that to the list of things to do to change the sound of the PL2500's.

I am not real sure what the 5 circles should do to the sound though. Maybe Fitz or another head-fi'er can give us some pointers on this.

 

[tako_tsubo]

Thanks runnin and Fitz for these mod suggestions. I take it that if I like the Bass the way it is, and want to tame the treble a bit is to experiment on the "small hole cover-up" and the final felt layer...assuming mine has the large holes. Too bad I am headed for Denver tomorrow....and am at work now.

 

[jgonino]

I would think they are acting as damping for the metal housing. Kind of like the little pads that drummer's put on their snare drums.

 

[runnin17]

Quote:

Originally Posted by tako_tsubo /img/forum/go_quote.gif Thanks runnin and Fitz for these mod suggestions. I take it that if I like the Bass the way it is, and want to tame the treble a bit is to experiment on the "small hole cover-up" and the final felt layer...assuming mine has the large holes. Too bad I am headed for Denver tomorrow....and am at work now.

Just know that if you don't put any cotton in the bass with overshadow all of the soundstage. I tried the mod with no stuffing behind the baffles and all I heard was bass. It sounded more like DT770's to me, but the bass was still a bit more detailed.

Personally if you like a ton of bass, then just put a very small amount of stuffing around the edges and not in the middle behind the baffle. Feel free to experiment and let us know what you find out though.

 

[runnin17]

Also, I was reading the Ultrasone 650 mod thread and you could put dynamat behind the baffle. I am not real sure what this would do to the sound and at the moment I don't have an extra $25 lying around to test it out.

 

[Fitz]

Mechanical damping (dynamat) wont do as much for the headphones compared to acoustic damping (such as the stuffing). I pretty much quit experimenting with mechanical damping for headphone mods a while ago, as I prefer to keep it simple and just go with the things that cause the most noticable changes.

@tako_tsubo:
You'll probably want to add some amount of stuffing even if you like the bass the way it is. I found the bass much too powerful with no stuffing, moreso than the stock levels. If you get something with a fairly even consistency (not in little pieces like runnin17's), then it'll be pretty easy to tune with just a small amount.

 

[runnin17]

Quote:

Originally Posted by Fitz /img/forum/go_quote.gif @tako_tsubo: You'll probably want to add some amount of stuffing even if you like the bass the way it is. I found the bass much too powerful with no stuffing, moreso than the stock levels. If you get something with a fairly even consistency (not in little pieces like runnin17's), then it'll be pretty easy to tune with just a small amount.

Thanks for that advice. I am going to be doing some errands today and I will look around for some more consistent stuffing to put in place of the cotton. The cotton is just a temporary measure to see how much bass I can stand with the treble balanced.

 

[tako_tsubo]

Thanks a bunch. I think I found some stuff here at work...cast padding should work and it comes in layer sheets...

 

[Kees]

Quote:

Originally Posted by jgonino /img/forum/go_quote.gif I would think they are acting as damping for the metal housing. Kind of like the little pads that drummer's put on their snare drums.

They do.
I have the version without these patches and I modded them glueing thick felt all over the metal, leaving only the perforated circle open.

Glueing the felt to the metal changes its resonating properties. Brings the low-end and the midrange better in balance and removes some of the metalic/plastic quality of the sound.
I am still not completetly satisfied with the highs, but I am working on that.

 

[runnin17]

What type of glue did you use? When it comes to putting glue on those baffles it scares me a little. I would hate for it to somehow get hot and melt into the driver.