When using customs and balanced armatures, some things are very important. The fit, because that will influence the sound quality a lot, and the fact that Balanced Armatures do not sound “warm” and “smooth” like dynamic drivers. I recently read a review of a custom iem by someone who started off by saying his fit wasn’t good and that one unit kept falling out of his ear, he then continued by saying the sound quality was awful. Go figure.
Another very important thing is that these BA4 are very sensitive in the way that if you have crappy source files, you will get really crappy sound. But look at it the other way around: when you have good files, like most of us who are serious about audio have, the result on the BA4 will be impressive. The clarity and detail level is impressive.
But let’s get serious now, how does the BA4 really sound? Well, in general you can say the BA4 is a neutral sounding and linear tuned earphone. Neutral and linear however does not mean boring sounding and it’s actually very musical and because of it being the original F(un) version, the bass is perfectly tight, deep and has just the right amount of body without getting out of line. The optional R(eference) version has less bass body.
Overall: The BA4 is very accurate. Two keywords are Clarity and Detail. These monitors have heaps of that but only in a good way, they never get boring in any way. Sound stage is good too but they could be a bit wider leaving more space between the instruments. Left-right balance and positioning/3-dimensionality are exceptional, another very strong point that combined with the clarity and detail make a terrific sounding monitor.
The BA4 doesn’t really need amplification but I would suggest using an amp at all time as it definitely makes the BA4 perform better. I myself used it continuously with the Cypherlabs Theorem (which is a high-end portable amplifier with a neutral and very spacious detailed sound) and with the JDSLabs C5D. (review soon!)
Bass: Great deep bass if called for with several layers of detail. Bass is tight, fast and has a good punch, it doesn’t overpower any of the mids. Bass body is in line with the rest of the sound, that means it isn’t especially boosted like most popular iems nowadays. This means this monitor isn’t for the regular bass head wanting big body bass, they will need to have a look at another monitor configuration. I myself can appreciate some extra bass sometimes and with some dance music I turned to the C5(D) amp by JDSLabs where I used the Bass Boost to get that bit extra. The overall sound quality compared to my regular setup (the Cypherlabs) dropped, but bass body was “upped”. For all other musical genres however ninety percent of the time I just used the Theorem amp or the C5D without bass boost. If your fit is right, bass will be good.
Treble: Is extended and very clear with lovely detail. Well controlled highs. Treble was implemented well and it’s especially audible with high quality recordings. In all honesty I do think treble could be further extended but it did not really bother me.
Mids: While the mids are not the warmest or most romantic sounding, I find them to fit in perfectly with the bass and the treble. I like the mids but at the same time I don’t feel there’s something specific to report about them. The real strength of the mids and the BA4 is that it all comes together perfectly as a total, you get a complete clear detailed sound with good bass and everything just fits right in. That’s what makes this monitor so great.
Gear & Conclusion
I’ve been testing the BA4 mostly with the Cypherlabs Theorem and an iPod but also with the JDSLabs C5 and C5D and Fiio’s X3 player. The big advantage with the last one is that you can EQ the bass a little should you want that (instead of using an extra amplifier). As usual I threw all musical genres at it from Classical to Blue Grass to Jazz and German Rap (yes, rap is everywhere nowadays) and I liked it all just as much. Only genres needing big body bass might require another configuration. And again, that doesn’t mean bass isn’t good. It is! There’s a big difference between bass quality and body/impact.
So in the end I can only confirm Cosmic Ear’s “jewel in the crown” statement*. Ever since I received and started using the BA4 I haven’t used a single other IEM for my listening pleasure. This thing is so good overall that I don’t ever want to go back to universal iems. (fit and sound quality). I wonder how the six driver version will sound and I think I have a pretty good idea looking at sound stage, treble extension and maybe even the mids section (Bigger body).
The BA4’s price starts at 330€/$450! I don’t think there is a better price/quality value on the market. That combined with the excellent customer service makes this BA4 definitely a winner.