The Sennheiser HD518, it just needs to gain some weight
Feb 10, 2012 at 2:40 AM Thread Starter Post #1 of 24

Magick Man

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I searched and didn't find a thread about modding the HD518, which is strange because it's a good candidate for it because they're: inexpensive, easily disassembled, and damned well just about everywhere. :D

Anyway, I was bored the other night, which is bad when I have my headphones near and modding materials next to my desk. So, I looked over my cans and thought it over, and decided on the HD518s. I bought these for my wife but instead of using them she stole my 598s, so they've pretty much been sitting here. Honestly, I wasn't impressed with them, their bass was too boomy and flabby, the mids were muffled, and IMO they had some funky resonance issues. People may talk about what a value they are, but to me they really weren't much to write home about. I would have sent them back but I procrastinated until the 30 day return window expired.

So I took them apart and poked around looking to see what could be done and I noticed that there's some empty space in there, and I thought, "I wonder what some mass loading would do?". So I got out the Plasticine (modeling clay) and set to work. For a couple hours I played around with varying amounts until I struck pay dirt. Add it just around the outer rim inside the cup, they're very sensitive to the amount used, don't over do it. And be careful not to get it on the back mesh, it's a devil to get out. Here:



The bass tightened up dramatically, the muffled mids were better, and the resonance issue disappeared. Wow, were these the same headphones? I was impressed. So I called a friend who is a Sennheiser/Beyer nut and told him and he asked me to stop by. So, I got there we hooked them up and he was quite surprised and claimed they sound more like the HD650 now, we got his and compared and he was right. They didn't have the breadth of soundstage but the tone was similar, as was the attack and detail. It's a nice upgrade and worth the clay and time, IMO.

Any other ideas?
 
Feb 10, 2012 at 2:44 AM Post #2 of 24
Huh, that's interesting.  Wonder if the results would be similar with a 595?  I tried modding it a bit myself...I just put a layer of acoustic foam on the inside of the baffles, basically closing it up.  It honestly didn't seem to have much of a negative effect on the sound, and it seems to have brought out the treble a bit...but I could be wrong.  It's hard to do comparisons after such a long time...I'd probably need to A/B with an unmodded pair to be sure.
 
Feb 10, 2012 at 11:46 AM Post #5 of 24
Well, it's already used extensively in modding the T50RP...


Exactly, that's what gave me the idea, working on my Rastapants. The amount of tuning for HD518s is crazy, though. Probably because they're completely open and have such high sensitivity, any amount of clay makes a difference.
 
Feb 10, 2012 at 12:14 PM Post #7 of 24
I will give it a try on my hd598, the earpads are removable arent they? how do I safely remove them?


You remove the pads by pulling on them, there are little snaps and they just pop off.
 
May 1, 2012 at 1:28 PM Post #8 of 24
Since you guys are the only ones I've found who are taking the HD 518 apart, is there any way you can tell if the drivers in the 5x8 series are the same?  It seems like they're at least quite similar, and I'm wondering if most of the sound difference is due to the padding and earcup tuning.  
 
May 1, 2012 at 2:35 PM Post #10 of 24
Damn you, making me wish I would've kept my 595s. For sure, this mod will "work" with any can in the 5XX Senn lineup (they all have the same basic physical shell, besides 580 obviously). The question is, what will it do to the sound for each model... I'd be interested to see more impressions.
 
Jun 13, 2013 at 11:11 AM Post #11 of 24
Trying this as soon as i get some modeling clay
 
Jun 13, 2013 at 5:23 PM Post #12 of 24
I recently got the 518s and while I like them, I found by simply placing my hands over the outer grill that the bass and mids evened out a bit, giving it a flatter and less veiled signature, at least to my subjective ears. At the risk of losing the soundstage (which isn't necessarily a deal breaker for me), I am curious how these drivers would sound in a closed configuration.
 
Sep 4, 2013 at 9:50 PM Post #13 of 24
I just got some gently used 518s to go to go with my modded 429s. Boy I got the bass sounding good on the 429s, one hole opened up with some blue tack in there. I definitely want to improve the 518s. They give me what I wanted in terms of openness and detail over the 429s but the bass does need some work. Did your mod lessen the bass or just tighten it up? I want to create an open 'phone with deep, impactful bass with the ability to eq it to giggle inducing levels. To much to ask? I'm using various sources with a FiiO e12
 
Oct 12, 2013 at 12:23 PM Post #14 of 24
So, I just picked up the HD598. They sound very similar to the HD518 (that I already own), apart from the bass emphasis of the 518, which seems to bleed into the upper range of frequencies, resulting in less clarity across the board. I suppose the 558 would be a happy medium between the two: fun mud vs. neutral clarity. Makes sense.
 

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