So, right off the back I have to say that the Sony XBA-4 is the most interesting universal balanced armature IEM I've ever heard. Now, before you think the hype train is about to roll out of the station, don't hold your hats down just yet so those won't get blown by the rapid winds. I'm not quite ready to make any definitive claim about the XBA-4 just yet, either positive or negative. But there are, however, some positive and negative things about this IEM.
Let me go negative first. And my negative comments mainly have to do with part of the build quality (which I rarely talk about, as I concentrate on sound). But I couldn't help but feel that Sony used some of the cheapest and lightest plastic they could find for the shells holding the electronics. I mean, holding the XBA-4 it feels like one of those cheap plastic toy shells you use to get when you put a quarter in one of those bubble gum machines in front of the supermarket door. Before I actually heard any sound I was thinking that they might have forgotten to put any BAs (or any other parts for that matter) inside. And the irony is that I thought the j-cord would bother me more, but it's made in such a way that I keep forgetting that there is a j-cord attached to the shells. Actually, I think that the cord and adapter plugs are done quite nicely, but only time will tell how long these light a-- shells will hold up. I can't say that they won't, but it doesn't feel like it. Maybe this is some new super light plastic they are experimenting with? Luckily, the Japanese store I purchased them from has given me their standard 1 year guarantee warranty (if there is a defect I'm suppose to send them back to the store I purchased them from and they will take care of everything).
Okay, now on to my initial impressions of the sound of the XBA-4: I'm still trying to get my head wrapped around the sound of these, but I can tell you a few things for sure: the XBA-4 has the widest soundstage and headstage of any universal BA I've ever heard. If it's not exactly there (not 100 percent sure of this since I don't have them anymore), the XBA-4 has damn near the same instrument separation and spaciness that I noticed when listening to the EX1000, and the XBA-4 is almost the complete opposite of the W4. Some grand statements, but that's how I am hearing them now. I'll comeback to the W4/XBA-4 comparison in a moment, but I also wanted to talk about refinement in sound as compared to the EX1000. This is hard as dynamic drivers seem to have a far different character than BAs. I will say that the XBA-4 is more refined than the EX600 and the 7550. It's quite close to the EX1000 in some ways from a refinement standpoint, but not quite there. Again, I think this has more to do with the different characteristics of BA vs. dynamic drivers. The XBA-4 is quite good.. Very good.
Now, comparing it to other BAs I'ver heard, in general I would say that the XBA-4 is one of the most transparent and clear BAs I have heard. It's not really super warm, but it's not super cold (analytical ) either. It's somewhere in the middle (which I like a lot). If I had to push it in one direction or another, I would push it more toward the cooler side. There is so much super space between instruments, and I'm loving that much in the sound. And the while the treble is sparkly and prominent, it's nowhere near as harsh as the treble in the EX1000 or EX600. but it is not as laid back as the highs in the 7550. Somewhere in the middle.
By the way, I'm doing all listening through the Fiio E10/E9 combo DAC/amp. Now, a little bit more about the differences between the XBA-4 and the W4. As I was hoping but couldn't tell at first listen, the XBA-4 is performing exactly how I hoped it would when using the sub-bass woofer. It only uses it when needed in the recording instead of keeping it firing with constant deep muddy bass. This gives a nice rich quantity and quality of bass when the music calls for it. When I first heard them it sounded as if the sub-bass might remain constant and muddy, but this is thankfully not the case. The W4 on the other hand has a denser and less airy bass. What do I mean by this? Well there seem to be air between the bass notes being plucked in the XBA-4 than the W4. Now, I know some of you are saying to yourselves, "But isn't the W4 bass-lite?" Not really depending on the seal and the tips you use. By me using the long silicon Earportz tips on the W4, I get rich deep bass (with sub-bass). The bass, however, is more compact and dense in the W4. I can't think of any other way to explain that bass right now, but I will give more clarity about what I mean as I think about it more.
The W4 was the king of instrument separation for me in the land of universals (beating out all BAs I've heard and really all dynamics except the EX1000). It doesn't, however, beat the XBA-4. The Sony makes the music sound more 3-D - as cute told me awhile ago in an inbox - whereas the Westone is great but more 2-D sounding. The W4 is also flatter and has a more boring sound, but I still love the W4's sound. I can't put my finger on it, but the W4 has an intoxicating sound - especially for when I'm listening to jazz. I think drums sound more natural and dynamic in the W4 (not that the XBA-4's drums are bad at all - and the king of drums in a universal still belongs to the GR07 IMO).
So instrument separation is wonderful in the XBA-4, and vocals don't sound recessed. But the vocalist does sound like she/he is in a space a good distance from the rest of the musicians. Mids are not recessed, but aren't forward. I would say these IEMs have a slight U-shape.... Great separation of lead vocals and background vocals. I'm listening to Dr. Buzzard and the Savannah Band now - Cherchez La Femme/ Se Si Bon - and I'm hearing handclaps in the backing vocals that I've never heard before. The bass has fantastic slam.
As I said earlier, these might satisfy a basshead, but don't come to this IEM thinking it's a "basshead" earphone. It's not. Sub-bass is there to do it's job - as if you had a subwoofer connected to your high-end audiophile stereo system. A good subwoofer gets out of the way when it's not needed. This is where I think the W4 fails in comparison. I don't think the sub-bass really gets out of the way if not needed. Again, I still say the W4 sounds great, but this is my observation compared to the XBA-4.
The XBA-4 execution of the subwoofer actually reminds me more of the sub-bass in my 1964-Q, but the universal's sub-bass doesn't slam as deep - to my ears - as the sub-bass slams in my custom. I guess from what I've written thus far it is a far assessment to make that I like the XBA-4, but as for ranking them I still don't know where. The lightness of the shells is still bugging me and I'm feeling like some weird trick is being played on my when I listen to the nice sound. But the plus side is that you dont' really feel them in your ears (yes head-fi family, the XBA-4s look bigger and more uncomfortable than they are. Actually they aren't uncomfortable at all). Okay, that's it for now. Feel free to ask some questions. I'm going to do some more listening.
Almost forgot, electric guitars and acoustic guitars sound wonderful with the XBA-4. Cellos and strings sound fantastic. As far as BAs, sound is leaning more toward the TF10 (but it doesn't sound like the TF10, just leans in that direction more so than the W4). It sounds nothing like the SM3 or SM2 because of the wide soundstage and instrument separation. The SE530-535 mids are more forward. Hmmm? If I'm not going strictly by other BAs, the sound is a mixture of the GR07, TF10 and EX1000 (if that is possible at all). That's how I'm hearing them now. Happy listening...