[HolyCheese]

I was wondering if anyone ever tried to mod the HD518's?
 
I just tried it and so far I find the sound to be improved quite a bit.
The unmodded HD518's bass sounded not really great in my opinion. (I must say i'm no pro audiophile and don't own load of high end stuff) mind that I don't own an amp yet and that I run them directly off my Zune HD. A few terms that come close to what I think they sound like:
 

Bloated

 - Excessive mid bass around 250 Hz. Poorly damped low frequencies, low frequency resonances. See tubby.

Blurred

 - Poor transient response. Vague stereo imaging not focused.

Boomy

 - Excessive bass around 125 Hz. Poorly damped low frequencies or low frequency resonances.
 
 

Dark

 - A tonal balance that tilts downwards with increasing frequency. Opposite of bright. Weak high frequencies.
 
I don't really recognize the bumps of frequencies. If I describe the sound with my own words then the bass sounds very undefined, low detail and a bit too much. Vocals are a bit on the soft side. Overal sound quality and detail is still impressive tough.
 
I noticed that the sound changed when I lay my head on a pillow (while wearing the headphones) so I decided to mod them. I tough why not and my new ATH M50's can arrive any moment anyway.
 

 
I cut the pointy things off and made it large enough to cover all the holes on the side of the headphones. Then I put this stuff under my driver.
 
When I listen to them now the bass has definitely improved. It's alot less, maybe a bit too much, but it sounds much better. The sound has become more flat and the vocals/mids are no longer off lower volume. The bass extension tough, seems a bit worse. The overall quality is a only slightly worse and you have to increase the volume a bit more. I don't really mind because overall the headphones are a more pleasure to listen to and they are still very easy to drive.
 
 
 
If anyone is interested I can make pictures of what it looks like and how i've done it. Just let me know
 

 

[Focker]

These were the first headphones I ever bought...picked them up back in Oct or Nov. I sold them for the very reason you've pointed out - the bloated, muddy bass. It was ok for movies on the laptop or something, but for music I hated it. I also found them unreasonably hot to wear more than about 30 min or so.

 

[HolyCheese]

Allright, glad to hear that it isn't only with my headphones. About it being hot. It's a bit true but I don't find it too hot, I can easily wear them for 2hrs+

 

[HolyCheese]

The sound definitely increased. It's worth a try if you don't like the sound

 

[DannyRox23]

I have the HD518, HD650, and HD800. The HD518 were my first pair of Sennheiser headphones and have to highly disagree with your opinion. In my opinion, they have great audio quality. I have no mudding problems with them, nor do I have any mid/high problems. They sound fine as is and to tell you the truth, I would stay away with the modding stuff because it could lead to damage. When I was 14, I was always taking apart headphones to mod them, and always broke'em. I'm pro at modding now, but I only mod headphones that are about $100 or less.
ANYWAY - the mod you have pulled could make the phones sound even worse. Your letting the sound waves reflect back onto the speakers and your not letting them escape from the vents (Which is the point of the vents in all Sennheiser Audiophile products.) You do not like'em? Well, that's your opinion. I know their not great, but their great for their price and you can at least say they sound better than Beats Pro. The Beats are horrible, end of story - well, their not worth what their cost.
Hope I helped

 

[xuxoemc2]

Thanks, this helped me a lot, I'm between the HD 518 and 558, do you think the extra price worth it?

 

[HolyCheese]

Hey I'm back with alot more experience.

That depends you personale preference. What kind of sound do you like? The hd518 are a bit darker and the 558 has more highs.

Its like the 600 vs 650. Instead it's 558 vs 518.

overall the 558 are a bit better but sound preference is more important.

 

[xuxoemc2]

It's for gaming mostly, and for music is for classic and rock mostly. Thanks for your reply!

 

[HolyCheese]

Then I'd suggest the 558 for both gaming and the Music that is a better option.
What do you connect it to?

 

[xuxoemc2]

Still dont have a source, i'm thinking to get a xonar dx or dg

 

[HolyCheese]

Well what motherboard do you have? I used mine for a long time on a sabertooth 990 fx and that sounded prety good. Now I use it with the FiiO e10 and I find that a good combi. You could try to find that for +-65 euro.

 

[shtldr]

Alternatively, it's possible to reduce the bloated bass and bring out the upper range on HD 518 by sticking some cotton behind the driver. The advantage compared to the OP's mod:
 
You can open the headphone only once, remove the back rim and grill, then put them back together. This leaves you with only a plastic frame behind the driver. Cotton is easily inserted and removed through the frame which lets you experiment without having to disassemble the headphone repeatedly. The more cotton is put atop of the driver's paper rear cover and the vent hole in the magnet, the less bass and more upper mids and treble there will be. More cotton also narrows the sound stage.
 
One only needs to take care that cotton fibers do not get into the holes and into the driver.
 
The grills and the rims can also be put back without disassembling. Doing so slightly reinforces the overall effect of the cotton so you may need to use slightly less cotton to account for that.
 
HD 238 can be modded in a similar way (although I haven't removed the grills and had to dis/reassemble on each attempt) and the sound can be even better than HD 518, as they don't seem to suffer from the big treble dip that the HD 5*8 line has.

 

[DannyRox23]

  Alternatively, it's possible to reduce the bloated bass and bring out the upper range on HD 518 by sticking some cotton behind the driver. The advantage compared to the OP's mod:
 
You can open the headphone only once, remove the back rim and grill, then put them back together. This leaves you with only a plastic frame behind the driver. Cotton is easily inserted and removed through the frame which lets you experiment without having to disassemble the headphone repeatedly. The more cotton is put atop of the driver's paper rear cover and the vent hole in the magnet, the less bass and more upper mids and treble there will be. More cotton also narrows the sound stage.
 
One only needs to take care that cotton fibers do not get into the holes and into the driver.
 
The grills and the rims can also be put back without disassembling. Doing so slightly reinforces the overall effect of the cotton so you may need to use slightly less cotton to account for that.
 
HD 238 can be modded in a similar way (although I haven't removed the grills and had to dis/reassemble on each attempt) and the sound can be even better than HD 518, as they don't seem to suffer from the big treble dip that the HD 5*8 line has.

I know that this post is old, but you are absolutely wrong. Closing the headphones will increase the bass amount. Soundstage is created when the grill is open and NOT closed. Soundstage also depends on the angle of the drivers and the amount of room of the ear cups. This mod destroys the soundstage and will make all frequencies unbalanced due to no space of excess sound to escape. The best thing to do, for the 518, is to remove the old grill and replace it with a simple mesh grill. The mesh grill will give it plenty of room, for sound to escape. This will surely improve the soundstage and quality. Other than that, I don't see any other way to improve the quality. Maybe comfort can be improved with using other Sennheiser ear pads (like the HD598.) Good luck!

 

[shtldr]

Cotton does not stop bass (try stuffing it in your ears and listen). I'm no sound pro but a layer of cotton sounds like a low-pass filter to me. It lets bass escape out of the headphone and just mids and treble is affected (treble being affected the most).

 

[Mik James]

  I know that this post is old, but you are absolutely wrong. Closing the headphones will increase the bass amount. Soundstage is created when the grill is open and NOT closed. Soundstage also depends on the angle of the drivers and the amount of room of the ear cups. This mod destroys the soundstage and will make all frequencies unbalanced due to no space of excess sound to escape. The best thing to do, for the 518, is to remove the old grill and replace it with a simple mesh grill. The mesh grill will give it plenty of room, for sound to escape. This will surely improve the soundstage and quality. Other than that, I don't see any other way to improve the quality. Maybe comfort can be improved with using other Sennheiser ear pads (like the HD598.) Good luck!

 
I know this post is old ( 

) but you completely missed the point!
Shtldr did not specify a closed design, it is an open design with cotton dampening. On a side note, the bass in any sealed enclosure (with a particular driver is entirely dependent on the size of the enclosure and dampening material within the enclosure.
 
The more you know