Been a while since I've posted in this thread. And for anyone else too. I've recently started reusing my original K550s very often. I bought these:
https://www.ebay.co.uk/itm/Thick-Le...var=552352398906&_trksid=p2057872.m2749.l2649
You never know if you can trust Ebay, but these pads are significantly better quality than the originals. Within 2 years of use, the original pads seem to get to the stage of when they stretch, the material just rips. This is so thick that you couldn't rip it if you tried. Yes, it isn't real leather, but well worth just over £5. Much better value than when I bought a spare pare of originals for my K550 MkIII which were £36! And these are identical to the originals, which unfortunately just don't feel like they will last as long. These new ones do use different foam, which I'm not so keep on. It is very firm in comparison, making the ear pads not feel as soft. I never have this problem that others mention. A lack of clamping force that results in lacking bass. But these could well improve that. But I just used the softer foam from the originals and I prefer it that way as they don't press as firmly against your head. (firm foam is in the left of the picture) I like that you can get the pads in grey like I have. There is something about them that make the K550s look older than they are, but in a good way. The material on the back of them that slides into the plastic ring of the plastic surrounding the driver isn't as wide as the originals though. I found they pulled off a bit too easily. So I put them around the metal edge and that works out perfectly. Hiding all the dents and scratches and making them look nice again.
I've also bought a replacement headband pad as the other one I previously had with poppers has started to peel where I had to shorten it. I've now bought a genuine Sennheiser 280 pro headband. That doesn't need shortening. It is just a little bit slack so it occasionally slides about a bit. I may need to think of a way to prevent this. But you do notice that the foam is thicker than what the original K550s have and it feels nicer on your head.
The main reason I stopped using my original K550s was because of a popping sound when any pressure gets put against the ear cup. If you remove everything from the 3 holes in the ring under the ear pad, this problem almost totally goes. But then the sound is awful. The bass may still be very deep, but it lacks impact and the midrange is terrible. Clear but so thin and harsh. Similar with the treble. That top end spike just becomes too much. So as I've tried before, I tried covering up the holes. If I use PVC tape over all 3, they then sound simply excellent. Everything is then as good as my MkIIIs. But the issue is that the driver pops and crackles every time that I move. I know what causes this, but don't know why. It is to do with the air pressure against the driver. When the holes are open, the air can escape down them resulting in barely any pressure being put against the driver. If you used ear pads that had holes in the underside of them going to the foam, that would sort this problem out, but then you would loos a significant amount of bass as it would get absorbed. I don't know how they have got to be this way. My MkIIIs don't have this problem and their holes are covered up. But then my first K550s never used to. I think something must have weakened the driver. Although they never distort. The solution I've found is as one of my picture shows. PVC tape fully over 2 of them and almost completely over the other. This then at least allows a little bit of air to go back in, which means they only have this popping problem if i try to press against them or suddenly move. The midrange is not quite as good as my MkIIIs like this, but they are very listenable again. At one stage, they didn't get used for over 6 months. Now, I have upbraided my cable and use these for home use and keep the MkIIIs with the detachable cable in my bag with my FiiO X3 for portable use. As my profile picture shows.
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