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HD25 super isolation circumnaural mod

post #1 of 5
Thread Starter 

Didn't know where to put this because it's a cross between full-size and portable now, but mods feel free to move it if you deem necessary.


Anywho, I'm going to Europe next week and decided I needed a good isolating set of headphones for the plane. Naturally, I bought an HD25 because of its great passive isolation. I just got it in today, and decided the isolation wasn't where I wanted it to be. It was good enough, but not extraordinary. When do we ever leave things at good enough in this hobby, anyways? So, I decided to do something about it.


I recently bought these earmuff protectors off Amazon:



and the Sennheisers fit inside perfectly! So I now knew what I had to do. I wanted to keep the headphones relatively stock, though (to not butcher the resale value) so I had a dilemma. After mulling it over, I decided to add some 3.5mm jacks to the HD25, stick them inside the earmuffs, and make a cable with mono plugs on the end. This way, I could keep the whole cup structure, damping, etc. stock. So now, I can pull the HD25 cups out of the earmuffs, attach them to the stock headband, attach the cable, and I have my original HD25 back! (with the addition of mono jacks on the bottom of each cup).


Enough text, time for pictures:

Wiring in the new jacks (with nice silver wire, too!:

photo 1-1.JPG


Bottom view of the jacks:

photo 2-1.JPG


Inside the earmuffs:

photo 3-1.JPG

photo 5.JPG



So, how did it work out? In my mind, fantastic! I didn't get to spend more than a couple minutes listening to the HD25 stock, but I think the sound is mostly unchanged (at least running off of an iPhone, which is what I will be using these with). Very smooth and a nice bass thump. There might be a slight decrease in bass compared with the stock HD25, but I'm not positive because I only listened to the stock one for one or two songs. If it is decreased, it is not decreased by more than what the iPhone "bass booster" EQ does (if you set the EQ to bass boost I think the bass is more than stock HD25). As for the isolation, it's just awesome! If you thought the stock HD25 had good isolation, just wait till you hear this! It's on par, maybe even better than my Etymotics with triple flanges. Don't have them next to me at the moment, so I can't do a direct comparison.


Stuff I still have to do: seal around with cable entry with some silicon to increase isolation even further, paint the cups black.


What do you guys think? Any suggestions of what else I could do? I was thinking about making a silver cable for them too, but that probably wouldn't make much of a difference running just from an iPhone, and I didn't feel like putting all the effort into it right now haha.

Edited by pbandstefanwich - 7/12/11 at 10:43am
post #2 of 5

One of the best parts of the HD25 is the body, now, I thought of this with some KSC75 drivers, but I don't want to wear the god awful cans. If they make a better looking set that can fit the drivers, that will be my day!

post #3 of 5

this is crazy eek.gif

post #4 of 5

Good thinking, good work. Very interesting to see the HD25 drivers uncovered as well.

post #5 of 5


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