Review Written by @Precogvision
DUNU is an older Chi-Fi company from which I’ve reviewed a number of IEMs in the past. While most of said IEMs have failed to tickle my fancy, DUNU has firmly established themselves as one of my favorite brands - and for good reason. They are extremely receptive of feedback, and the level of transparency with which they conduct themselves is laudable. So when I received a sneak-peek of the SA6’s tuning, you can bet I was excited to see what they’d cooked up. It seems I wasn’t alone either; while the SA6 has by no means enjoyed “hype” status yet, it’s been steadily making rounds in the IEM community since its release. That in mind, read on to find out what DUNU’s first 6BA IEM brings to the table.
This unit was kindly loaned for review by DUNU. Thank you! At the end of the review period it will be returned, and as always, what follows are my honest thoughts and opinions to the best of my ability.
Source and Driveability
Like most BA IEMs, the SA6 is on the easier side of things to drive, and I had no trouble running it off mobile devices. Hissing was a non-issue. All critical listening was done off of an iBasso DX160 (volume ~10) and A&K SP1000M (volume ~40) with lossless FLAC files, the stock tips, and the stock cable.
Because I received Tom from DUNU’s personal unit, what I received will likely not be indicative of everything in the retail packaging. I assume, however, that you will at least get the standard carrying case, an assortment of tips, and the swappable connector jacks.
Speaking of which, let’s talk about those swappable connectors. Since when did anyone ever enjoy swapping the entire cable off their IEM just to play it off a different source? Since never, and frankly, it blows my mind how insensitive most cable manufacturers are to this inconvenience. The way DUNU’s modular connector works is simple yet elegant. You simply line-up the triangle and circle (male/female) inscriptions, and it’s plug and play from there. While I won’t attest to this from a sonic-quality standpoint (to spare myself ire), on a practical level, DUNU makes some of the best cables on the block, so much so that I was compelled to purchase one of my own!
I also really like the build quality of the SA6 itself. The faceplate is of stabilized wood and the body of acrylic. It’s worth noting that it’s random which color faceplate you get; nonetheless, I’ve yet to see an SA6 faceplate I dislike. I’m also happy to see recessed connectors on the SA6. This is a critical stress area, and as usual, DUNU’s attention to detail is evident. I had no issues with fit either, and the SA6 is a very comfortable IEM for my ears. Obligatory your mileage might vary and all that, as fit (and aesthetics) are 100% subjective.
Frequency response taken off of an IEC-711 coupler. There is a resonance peak at 8kHz; as such, measurements after this point should not be considered accurate.
The SA6 follows something of a U-shaped frequency response; while I’m not sure if I would call it a studio response per se, which brings to mind something more reference-y, it’s unmistakably a well-tuned, balanced IEM. Let’s briefly talk about what the “Atmospheric” mode or switch ‘on’ position does. And well, the answer is...not much. It sticks on 1-2dB to the sub-300hZ range, lending the SA6 to an ever-so-slightly warmer sound by virtue of more bass and lower-midrange presence. I mean, I’ll take it? I wish it had a more profound effect, but I also like that you can adjust the switches without the use of a tool.
I’ve done some back-and-forth on the SA6’s bass response. The SA6’s low-end unmistakably decays like a BA (read: it has none), and there’s a plastickiness to its transient behavior that’s only exacerbated by flicking the bass switch ‘on’. But I still wouldn’t hesitate to say that SA6’s low-end seats itself in “above average” territory, enough to partially fool me the first time I heard it. The SA6 uses vented BA subwoofers, and it carries over desirable dynamic driver characteristics, namely slam and texture, which are present if only in moderation at the expense of some transient attack. While the SA6’s not redefining my benchmark for BA bass anytime soon, it certainly leaves me interested to see what’s possible using these subwoofers in the future.
The midrange is the most solid part of the SA6’s tuning in my opinion. Granted, there are small signs of disjointedness, like the more relaxed ear-gain contrasted to the 4.5kHz bump which skews the note weight ever-so-slightly thinner and doesn’t quite sit natural to my ears, and intangible issues I’ll delve into later. But I have to admit I really like the SA6’s midrange. It’s one of those midranges that doesn’t quite excel at anything, but that is really quite commendable by virtue of how little it does wrong - and really, that’s all you can ask for at this price point.
The SA6 exhibits a strong dip at 5kHz into the treble, which lends itself to preventing sibilance. This is eerily similar to the qdc Anole VX’s treble dip, a treble response I abhorred for its grating distortion. Suffice it to say I’m not a big fan of the SA6’s treble either, although for an entirely different reason: it’s surprisingly uneven. To my ears, the SA6 exhibits a bump at both 7kHz and 13kHz after which it begins rolling off. A non-linear treble response is not necessarily a bad thing; for example, the 64 Audio U12t exhibits a treble dip post-8kHz and a series of 15-17Hz peaks. That’s been tastefully done in my opinion. So why might this work for the U12t but not the SA6? I suspect it’s because 15kHz is at the cusp of which the average individual’s hearing begins to roll-off. The U12t’s absurd boost at this frequency compensates for said roll-off, and it lends to the perception of exceptional micro-detail up top. On the contrary, because the SA6’s peaks are (relatively) lower in the frequency range, the decay of instruments often comes off as mildly puffy, perhaps swelled, helped in no part by the quicker rolloff post-15kHz.
Of course, as a general disclaimer, recall that frequency response measurements are not accurate after 8kHz and that all of this is pending your individual hearing, as I see no shortage of varied impressions regarding treble. And make no mistake: The SA6’s treble is by no means offensive. Heck, it’s pretty good for the price; there’s just a vague sense of something being ‘off’ and lacking in je ne sais quoi to my ears.
It stands that a good tuning doesn’t necessarily translate to a good IEM, and indeed, the SA6’s technicalities are more middling (in the grand scheme of things) albeit competent. It does seem to struggle with layering in particular. Layering for me is simply the distinction with which an IEM is able to create a sense of space, or physicality, between instruments. Like so, the SA6 has a tendency to squeeze - and on more complex tracks borderline smear - instruments, especially those in the center image.
And if we’re going to get real nitty-gritty, there’s something disconcerting about the SA6’s macrodynamic ability contrasted to the midrange and treble. The midrange and treble both exhibit an elevated, thin quality to their transients, nigh ghastly, that pop all the more unnaturally as a result of the SA6’s surprisingly good dynamic contrast. Subsequently, there is a certain stridentness - not an outright one - to the SA6’s presentation. While this “overly loud” or upwards compressed quality is not uncommon to BA IEMs, the SA6 seems stuck somewhere in-between: neither flat nor particularly dynamic, yet perplexingly fatiguing at times. This is a good (and all the more unfortunate) example of poor synergy on an intangible level that could have been avoided had the SA6 been plain “average” in the macrodynamics department.
I need stress that my expectations are unreasonably high. These are all minor gripes that should be expected at this price point, and while the SA6 won’t be taking home any awards for its technical performance, again, it’s competent for what it is. I was also pleasantly surprised by the SA6’s image diffusal, or the extent to which an IEM is able to create a sense of space around the listener. It’s by no means mind-blowing, but this is something that DUNU’s other IEMs seem to struggle with, and it’s a good distinction between “average” and entering “above average” imaging for me.
This is the 4BA/1DD hybrid of DUNU’s lineup, the most natural comparison given their respective price points. Frankly though, I’m not a big fan of the DK-3001 Pro. For all my gripes about the SA6’s treble, it’s a far cry from how rolled-off the DK-3001 Pro’s sounds. Said rolled-off treble negatively impacts the DK-3001 Pro’s timbre, lending itself to a smothered by BA “artifacts” characteristic and killing the IEM’s dynamic range. Really, the allure of the DK-3001 Pro is that it’s safe. But with the SA6 in the equation, I think we have a clear winner: The SA6 has a solid technical edge - particularly in terms of image diffusal - to my ears and better tonality to boot.
Here’s a very solid IEM in the $500 price-bracket. The S8Z follows a more neutral tuning with less sub-bass presence and a meatier midrange. The treble is where these two IEMs differ significantly though; the S8Z exhibits a strong lower-treble peak relative to the SA6’s dip. Go for the SA6 if you enjoy a more (relatively) laid back, yet detailed IEM, and go for the S8Z if you enjoy an aggressive, almost visceral presentation. Personally, the S8Z’s treble is a bit too much for my tastes, and I get the impression that the IEM is almost under duress, straining, in tandem with the BA timbre (mostly grain) the IEM exhibits.
Ah yes, the Blessing 2, the $300 “giant-slayer” that every manufacturer in this price-bracket probably despises. I’m inclined to say that the SA6 isn’t really “better”, at least in the sense that it’s neither tuned better nor more technical. But sometimes the whole is greater than the sum of its parts, and this is where the B2 stumbles hard. The B2 is simply not very coherent - from its nigh textureless bass to its perplexingly linear, yet gritty treble response - and it impresses the notion of something less than refined. When the SA6’s BA subwoofers produce comparable texture to the B2’s DD, you know something’s up. I know which one I’d take; of course, the SA6 is also $200 more. I don’t see any reason to purchase the SA6 if you already own a B2 unless you’re looking for a different flavor.
And speaking of different flavors, let’s briefly talk about the Dusk. The Dusk is essentially a thicker, bassier B2. For a basshead like myself, I really enjoy its tonal balance, enough to sway me toward the Dusk in terms of preference. I think the SA6 still has its appeal as a more coherent IEM, but these two IEMs really do belong on the same playing field in my opinion.
I’m well aware that this is a harsh review, but what strikes me as commendable is just how darn solid the SA6 is. For those who might not have read my reviews before, I often make a distinction with which I’ve reviewed an IEM. In this vein, I’ve held the SA6 to flagship standards, an unrelenting trial-by-fire I generally reserve for much more expensive IEMs. I’ve done so because I think reviewing the SA6 to the standards of the average IEM in its price bracket would be doing DUNU’s hard work - and my integrity as a reviewer - a disservice. And the best part? The SA6 has punched back at most every turn. Now, it’s still far from being a kilobuck heavyweight much less a top-tier IEM, but the SA6 unmistakably has what it takes to merit its price. And while the SA6 might not enjoy the hype that follows some of its peers, this is an IEM that I believe will stand the test of time as one of the few “very good” IEMs in its price bracket, one I am pleased to recommend.
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