I've spent some more time comparing these to my T20RP MKIII, and like some other people, I increasingly found the balance and bass to be slightly off compared to the stock sound of the original T50RP. I have no desire to open them up, so against my own recommendations in that other thread, I did some pad rolling. My theory is that the combination of the velour and the vent holes on the inside of the pads are eating too much of the bass energy. Here are the results:
1. Stock T50RP Pads
Eww. I love these on an unmodded pair, but the tunings they did on these make the stock pads sound like crap. The bass was bloated, and there was no control through the rest of the range. Not recommended.
2. Angled pads from the disappointing Fostex TR-70
These have some positives. The bass is definitely better, and it expands the soundstage nicely, but it creates a hollow sound through the upper midrange and are somehow even darker than with the hybrid pads. Some people may prefer them, but it's not recommended.
3. Brainwavs memory foam pleather pads.
These confirm my suspicion that the problem is those vent holes. If you wanted to try a budget fix, you could run a thread of electrical tape over the inner part of the pads, and see if that tightens up the sound for you. With these, the bass is more present, but still controlled. The soundstage is surprisingly deep, and they are a bit brighter. There's a bit more bloat to the overall sound, but I think that's inevitable if you want the bass response. My guess is that you'd get similar results from the Dekoni leather pads (not the ones with holes in them). These are the pads I'd recommend if you want to get a bit more punch in the bottom end without destroying the overall sound signature. I'm really not sure why they thought it would be a good idea to ship these with vented pads--perhaps they were made by people who wanted to emphasize the mids. Really, though, these make some really minor changes to the sound that help a lot.
I've had a pretty long journey now with the T50RP. I've had two pairs that I modded myself over the course of several years, owned the Smeggy made Thunderpants for a time, and have more recently been listining to a stock pair of the new T20RPmkIII. I've also, in that time, done some ortho driver transplants with the 40MM SFI drivers, and fiddled with some vintage Yamahas. I wouldn't consider myself an expert, but I have spent a lot of hours listening to what happens when you make various changes to spacing, damping, venting and weighing down planar drivers.
Ultimately, this always ends up coming down to compromise. If you want the magical and crystalline mids that orthos can deliver, it comes at the cost of bass extension and sound stage. If you want to blow open the bottom end, you can, but you will lose a lot of control in the upper midrange. If you want precision and balance across the spectrum, you lose some of the excitement of the crisp upper end. Even the Thunderpants, which were exceptional, came at the cost of weight, discomfort, and a lack of excitement in the treble.
I've only spent a bit of time with the T-X0 so far, but I'm impressed. It's not that they sound perfect, but have made a reasonable set of choices in order to make the right set of compromises. For people who care, I'm feeding FLAC tracks from Foobar2k through digital passthrough on a Soundblaster ZX into a custom headphone amp that can put 1 Watt RMS out at a 1ohm load, which is about perfect for planar headphones.
The midrange sounds lovely. It seems to handle male vocals a bit better than female vocals, because of a slight hump in the lower midrange, but vocals sound rich and warm. They get a bit lost during busier passages, but that's one of the main compromises, because it allows for excitement through the rest of the range. In Melody Gardot's cover of Over the Rainbow, her voice lacks the presence that I've heard on some other headphones, but it handles a track like Jeff Buckley's Lilac Wine really well, handling the vocal reverb nicely in isolation.
As someone who loves Beyerdynamic headphones, they are a bit darker than my tastes run. I'm not finding them as dark as some have been describing, though, and it keeps poorly recorded tracks from sounding too harsh. In Dave Brubeck's Take Five, it's possible to hear the space of the room in the recording, but not with as much clarity as I would like.
The bass, on the other hand, is spectacular, if a bit thin*. It's hard to get plenty of bass on these drivers while maintaining control, and it's always one of the key compromises I've needed to make with my own tinkering. Here, the bass is as close to good speaker bass that I've heard through headphones. On tracks like Infected Mushroom's End of the Road, the bass hits with power and authority, and holds up as the rest of the track gets busier. On tracks like Damien Rice's The Blower's Daughter, where unruly bass can overwhelm the rest of the song in the second half, the T-X0 still comes in with authority, but balances nicely with the rest of the track. It doesn't necessarily have the punch that others might look for, or that people are used to from non-studio cans, but it stays out of the way without being nonexistent.
So, they don't sound perfect, but in a world of compromises, I think these represent the best possible set of compromises that can be made, and they should make a good destination for this long T50RP journey I've been on.
A few other thoughts quickly:
-These remain highly resolving studio headphones. If you are listening to poorly mastered music with them or lousy sources, you're going to hear it.
-With the amount of damping here, I've had to turn my amp up higher than I'm used to on these drivers. They eat a lot of power, and really do need it. If you are finding they sound bad, it's probably a combination between bad sourcing and bad amping.
-I really like these pads. If I were to try a different pair, I would definitely move towards the thinner stock pads, not towards anything thicker or plusher. This should go without saying, but don't use pads with too much venting, or you'll kill the sound quality on these. If you are having issues with these pads, make sure that you are getting a good seal around your ears.
*This is the main impression that changed after some more direct comparisons and listening across a wider range of genres. I leave it here with only a few changes, since those were my first impressions.