Hybrids? Super-hybrids maybe? There are three different driver technologies at play with the Dunu Est 112 Hybrid in-ear monitors. Inside their machined aluminium casings, the earphones each contain three different types of driver. The bass drivers are 13.5mm dynamic drivers, the midrange and lower treble is handled by balanced armature drivers, and the extreme tremble is electrostatic.
tl;dr
- The Dunu Est 112 hybrid in-ear monitors are three-way, four-driver earphones employing three different driver technologies
- 5mm beryllium coated dynamic drivers for bass
- Custom Knowles balanced armature tweeters for midrange and lower treble
- Two Sonion Dual electret electrostatic supertweeters
- Machined, aluminium alloy casing with a “machined spiral pathway” for the signal to minimise standing waves and reinforce “sub-bass frequencies”
- Earphones weigh 9.6 grams (right) and 9.4 grams (left) according to my scales
- Cable employs MMCX connectors to earphones, so easily replacable
- 2 metre 4-Core, High-Purity Monocrystalline Silver-Plated Cable
- Terminated in connection which mates with included 3.5mm single-ended 90-degree plug, 4.4mm balanced 90-degree plug and 2.5mm balanced 90-degree plug – 3.5mm to 6.35mm plug adaptor included
- Nine pairs of silicone tips included, one set of memory foam tips included
- Carry case and cleaning brush included
- 10 ohms impedance at 1kHz
- 110dB sensitivity at 1kHz
- Less than 0.3% THD at 1kHz
- 5 to 40,000 hertz frequency response
- Available at fine high fidelity retail outlets, and direct from distributor's retail division here.
- Price: $849
A little more on the Dunu Est 112 hybrid IEMs
So, they are three-way, four-driver units, with two of the drivers being electrostatic. You may wonder how they manage this, given that electrostatic drivers famously require a high voltage applied to the diaphragm. It seems that the Sonion electrostatic tweeters are electret electrostatic devices. Instead of a bias voltage being applied, they employ a “dielectric” material with a permanent electrical bias. Included with these drivers is a matching transformer. My understanding is that this boosts the voltage of the signal for driving these electrostatic units. They remain (relatively) high voltage, low current drivers.
The Sonion electrostatics are designed for use as super tweeters, running from 7kHz up to 70kHz, although Dunu only claims an upper end of 40kHz in this implementation. Treble below that point, and I guess much of the midrange, is handled by a Knowles balanced armature tweeter. I don’t think I’ve seen any other brands specify Knowles as the source of their balanced armature drivers, but of interest it was Hugh Knowles who first developed balanced armature technology and the current company bears his name.
Bass is of course handled by the unusually large 13.5mm dynamic drivers.
The Dunu Est 112 IEMs are gorgeously built and provided with nine pairs of silicone tips of various colours, sizes and styles, along with one pair of memory foam tips.
The 1.2 metre cable is terminated on the earphone end with MMCX connections, and on the other end with what appears to be a proprietary connector, into which you can plug the included 3.5mm single-ended, or 4.4mm or 2.5mm balanced right-angle plugs. A 3.5mm to 6.35mm adaptor is included, along with a dual-prong airplane adaptor for the 3.5mm connection.
As you can see, with Dunu you have options. Also included is a neat leather-look carry case and a cleaning brush.
The two things to highlight from the specifications are the quite high sensitivity of 110dB (presumably for 1mW input). It would be wise to turn down your source before starting up your music. The other is the low 10 ohms of nominal impedance. That’s below specification for many source devices.
Listening
I am always a little trepidatious when I’m about to starting listening to the first ever track with a new set of IEMs or other earphones. I went through a lengthy period when nearly everything I stuck in my ears was painfully bright. Fortunately we’ve moved beyond that and there are now lots of fine-sounding earphones. Still, I don’t like dumping on a product, thus my concern.
So, I insert the Dunu Est 112 Hybrid IEMs into my ear. Then I do it again, getting it right. I’d selected the memory foam tips. On my first experience with memory foam tips a few years ago, I found them weird and creepy, but since then I’ve become a convert. They simply provide better isolation and seal than silicone, along with generally better stay-in-place security. The trick is to squeeze the foam down to the smallest possible diameter, insert them into your ears and hold the earbuds in place for perhaps ten seconds as the foam expands to make a good seal with your outer ear canals. The barrel of these earphones is reasonably large. I think my ears have fairly wide canals. I generally find that the best silicone ear tips for me are the largest, or occasionally the second largest. With the Dunu Est 112 Hybrid IEMs, scrunching down the memory foam, they inserted with a bare fit, so there wasn’t too much expansion required. If you have unusually small ear canals, you may not find the memory foam a viable option.
The reason I pulled them out and put them in again was because I didn’t realise initially that the section of cable close to the earphones was shaped to wrap around the ears. It doesn’t seem to be encased in anything special. Perhaps it’s just hardened a little into the right shape. Anyway, hanging them over your ears does a fine job of carrying much of the weight from the earbuds themselves, as well as providing insulation from cord tugs.
Speaking of which, there was very little transmission of physically-induced cable noise. In part that was because the cable insulation is particularly smooth, slipping over clothing with virtually no friction.
So, back to my trepidation. After all, until a few weeks ago, I’d never even heard of Dunu. Apparently they’ve been around since 2013, so they aren’t a fly-by-night outfit. But how would they sound?
Looking through the list of albums on the Astell&Kern A&futura SE180 DAP, the first to pique my interest was Billy Joel’s 52nd Street. Deep breath, plug into the DAP – I used the 4.4mm balanced connection – turn the volume way down to ensure I won’t blow out my ears, and hit Play. Phew!
The initial impression was a nicely balanced sound with no excesses in the treble, and a very solid bass end. Joel’s voice and piano was delivered with lovely clarity and power. Yes, Joel’s voice was slightly bright, with a little emphasis on the upper harmonics. The splashy cymbals on “Big Shot” were as splashy as always, or perhaps a little more. But every element of the music was there, nothing hidden or smeared. The dynamics were first class, and the drum kit was delivered in a particular thrilling manner.
(Why Billy Joel’s 52nd Street? Actually, it’s a rather well produced album and one quite familiar to me. Sometimes I eschew digital and go to my Columbia Half-Speed Mastered copy on vinyl which I purchased in the 1980s. After all this time, it’s still easily as good as the best quality vinyl you can buy these days.)
I passed briefly through Queen’s Sheer Heart Attack, finding the earphones fully capable of revealing how dreadful the recording quality is on this album. It’s best heard with boomy, low resolution loudspeakers. And quickly went to Pink Floyd’s under-appreciated album Animals (that was the one between Wish You Were Here and The Wall). The second track, “Dogs”, opens with an insistent acoustic guitar, with vocals quickly joining in. There was a slight crunch to the voice, an emphasis in the throat noises in the upper frequencies. That apart, the rendition was very solid. The deep bass was strong and accurate, particularly the kick drum, which was presented with real heft. When I got about four minutes in to the guitar “solo” (there’s a lot of multitracking going on here), the earphones are providing fine clean sound.
I was listening at a quite high level – they seemed a bit thin at modest levels, with a recessed upper bass. But turning them up produced a thrilling, dynamic and nicely balanced sound. (By turning them up, I mean pushing the volume control on an Astell&Kern A&futura SE180 DAP to 89 on the scale of 0-150, when using the 4.4mm balanced connection, or 102 on the scale when using the 3.5mm single-ended connection. These really are quite sensitive earphones.
I found it interesting that despite that slight emphasis of a kind of upper register vocal fry in their voices, there was only the slightest appearance of sibilance. It seemed to me that these earphones provided a slightly different look into the music.
Michael Murray’s performance on Telarc of Bach’s Passacaglia & Fugue in C minor delivered nicely on the bass pedal in the opening, controlled phrases, albeit with something of an emphasis of the noise in the recording chain (despite this being an early digital recording). When all hell breaks loose around eight minutes in, the earphones held things together very nicely and provided considerably better clarity and coherence than I’m used to on this piece of music. The deep bass remained solid, but again there was a softening of the upper bass that removed some of the sense of body from the music.
Then I switched over equipment and source. I used the Topping A30Pro headphone amplifier, driven by the Topping D30Pro DAC via 4.4mm balanced. I fed the DAC with TIDAL music in Exclusive Mode, Forced Volume and partial unpacking of MQA content by the app (the Topping D30Pro doesn’t support MQA). Lately I’ve been trying some of Bach’s Passions, this time the St John Passion. The version on TIDAL is recorded with nice air. The space this created was delivered by these earphones in abundance. Again, there was the occasional emphasis on upper midrange/lower treble. I think this improved air, while occasionally adding a little boost to edges of the male voices in particular.
A last little bit with TIDAL, Billie Eilish’s (of course!) When We All Fall Asleep, Where Do We Go. Again, there was that step up in output level in the upper midrange, making her voice a little breathier than usual, but the bass was deep, controlled and ever so clean. And seemingly limitless in output level, regardless of the package of frequencies being conveyed.
This is Dunu’s own frequency response plot for these earphones. If you’re new to looking at these, don’t be alarmed by the high frequency behaviour. This kind of thing is the norm for quality earphones:
But I would note that the elevated response above 2kHz and the dip in the region of 500 hertz explains much of what I heard. (I didn't find this graph until after I'd written my listening impressions.)
Compatibility
So, what about that low 10-ohm impedance? Did it cause any problems?
None that I could find. I tried the earphones on probably six different devices of varying quality, and all seemed happy enough. Remember, even though the impedance is low, the sensitivity is high so devices don’t have to be driven hard to produce high levels. For example, as I’m typing this paragraph I have the song “Westaway” from the debut Sky album streaming from TIDAL on an iPhone, and I’m using the standard Apple Lightning to analogue 3.5mm adaptor. Having the volume one notch above halfway is comfortable, two notches is verging on uncomfortably loud (the volume control on iPhones is rather course). On the next track (“Carillon”), at the almost too loud level, during the climax towards the end of the track, the mid-bass accompaniment did sound a little stressed, verging on buzzy. Could it have been the tiny amp in the adaptor running out of oomph? Or it might simply have been the earphones revealing detail in the music of which I’d previously been unaware.
A quick check – same track from TIDAL, using a Mac to the Topping duo and listening with the amazing Final Audio D8000 headphones. Ah, I could hear that same sense of compression, and a hint of the same thing in the bass that I’d heard with the Dunu IEMs. It was just that the tonal balance of the Dunu units was bringing it more to the fore.
I also checked on the amount of variation in the impedance with my standard 466 ohm in-line load (representing the type of headphone output on many home theatre receivers – see here on why I check this) and found a degree of variation in the impedance curve across the frequency spectrum. This is what that test looked like:
It produced a roughly 4dB range, peaking just a bit below 1.5kHz, bottoming out at about 5kHz and then heading back up to peak at 20kHz (and probably beyond – I only do this test up to 20kHz, but Sonion’s graph shows the impedance continuing to rise beyond that point). That would have a noticeable effect on tonal balance with such outputs, but the effect would be negligible for virtually all quality headphone outputs, which typically keep the output impedance below 10 ohms, and in many cases below 1 ohm. (At 4.7 ohms, the range would be just 0.04dB).
Conclusion
The Dunu Est 112 in-ear monitors offer a strong audio performance, lovely design and a generous set of accessories to help you get the best out of them.
