Man, that is a long and detailed read for $150 pair of cans…though they are a special pair, especially at the price.
I was just looking for/trying to follow the link to a graphic of the felt mod. But it might take all day to find that buried in the review/specs/measurements.
Anyway, some interesting reading…for when I have a spare week with nothin’ to do 
@Hellenback, Here is the link to 58x felt mod.
Any suggestions for equalizer settings for the 58x? I’m playing with the ES100 and these.
PDF of felt mod.
Cliff’s notes version.
Buy some 3/4 inch self-adhesive felt furniture pads. I used these. Note - thickness matters.
Drill or punch a 3mm hole in the middle. Go slightly smaller in 0.5mm increments to get less bass/more treble, or bigger for the opposite effect.
Remove the cables and remove the outer cages by hand, starting by prying off at the top (it helps to have fingernails)
Enjoy!
I used felt from Hobby Lobby. It does smooth out the sound, I think, but I don’t have a Sennheiser 6 series to compare it to. Still, for $150, these are really nice. Maybe this summer when classes let out I will audition a 600 or 6xx for comparison.
Thanks for direct and simple to access directions
I appreciate the other replies (but they pretty much sent me to the review tome that had me 
)
I do have some round felt stick-in pads but need to check if they’re the 19mm in the linked photo.
I’ll try to report back my personal experience when I get around to the mod on the 58X.
But in regard to the HD650/XX…
IMO, after many hours over years with the HD650, they hardly need any “less” of anything. Though I suppose I’ll need to listen before I pass final judgement.
Thanks again @pwjazz for the “quick & dirty” directions; it’s exactly what I was looking for👍
I finally got around to opening up the HD58X today. Have plenty of furniture felt in the garage and starting hacking away at it. I think I made my hole size about 4mm. It’s not very clean cut though as furries are cover parts of the hole. Will have to measure it a little later.
I wrote my review for this finally on my blog. In general, I do like it. It’s not my favorite headphone but at the price they are offered at, it’s quite good and mostly coherent. I didn’t like the uneven treble but that can be fixed mostly with the simple mod mentioned above. The rolled-off sub-bass was expected and not the end of the world. I also used REW to EQ it last night and the results are excellent.
Nice writeup! Both through your clear descriptions and through your overall body of work, I’ve learned to understand what kind of sound you like. Much as Tyll did back in his day, you’re able to help me understand not just how a given headphone sounds but also how it relates to your preferences, which taken together provides a useful reference for understanding what I myself might like. I much prefer this to the generic “bass good, mids great, treble okay, soundstage medium” kind of reviewing that tries to sound unbiased but in fact just makes it harder to tease out the bias.
Back to the topic of replacement pads, are the Dekoni the best in headphone town or are there others I should consider? I’m very close to ordering the hybrids for my 58x to improve the comfort. (Next will be a DAC/amp stack).
Thoughts on pads?
I have the hybrid pads and a 58X at home, I’ll mess with them after running errands today
I decided on the Yaxi Alcantra pads.
https://www.yaxi.jp/product-gallery/hd650/
I got a pair of Maxi pads for my HD25’s and they made an amazing difference in comfort. HD25’s are on-ear and have a pretty good amount of clamping force. The Yaxi pads made them wearable for longer periods.
They won’t be here for about a month (shipping form Japan).
J
How is the comfort compared to the original pads?
More plush…but they add pressure at the same time due to being thicker pads…this can be alleviated by slowly flexing the band away from the cups until it fits your preference.
Yep. I did that when I first got them. I set a couple of hard cover books between the pads and let them sit for a few days. Helped the clamping but I find the stock pads to be too stiff.
Based on my experience with Yaxi, the new pads should improve the experience. The other question will be if they affect the sound. I’ll post next month when I get them.
The Elite Hybrids definitely alter the sound. I find them more lively with the pad swap. I also have the Dekoni Elite Velour and Fenestrated Sheepskin pads. They all have affects to the sound but usually just, still very noticeable though.
Been contemplating aftermarket Sennheiser HD5/6XX pads for some time, as I find the Senn pads wear down too quickly, especially for the cost.
Also, I find the ear-cup depth to be slightly shallow and the opening a very little bit too small for longer periods, once they’ve been used for even a short period of time (i.e.flattened a bit).
I’ve held off because I’ve read the Dakoni opening has a bit smaller circumference, even if deeper.
I hadn’t yet read anything on the Yaxi ear pads so just took a look via the link provided above.
According to the PR blurb, the Yaxi have a slightly larger opening. So I’ll be very interested in hearing about anyone’s experience with the Yaxi ear pad, once some feedback is available on their quality, comfort and SQ.
