Nightjar Acoustics Duality Review - The Luxury Bass Experience

Introduction

Nightjar Acoustics is a Singaporean brand operated by the ingenious tuner, Chang, who’s also one of the lead figures behind the Subtonic brand. His personal brand has had a couple of IEMs so far: the Meteor and the Singularity. I was a fan of the Meteor; however, the Singularity left me with more mixed feelings. Despite its focus on bass and timbre, I didn’t feel like it was a standout for a single-DD. Enter the Duality, the Singularity’s big brother that adds another dynamic driver into the fray. Priced at $3000 USD for the base package, the Duality is clearly oriented toward the flagship stratosphere and listeners seeking an endgame, bass-head set. Let’s take a closer listen at whether it delivers.

This unit was loaned for review by Nightjar Acoustics. At the end of the review period, it will be returned. As always, what follows are my honest thoughts and opinions to the best of my ability.

In-the-Box

There were several packages available for the Duality based on when it was ordered; however, I was sent the base package. The Duality arrives in a medium-sized, hard-carry case. Inside are the following accessories:

• Synthesis, 2-pin 0.78mm cable
• Leather puck case
• Divinus Velvet tips ms/m/ml/l
• Subtonic tips m/ml/l
• Impedance adapter

I’m a big fan of the Duality’s Synthesis cable - it’s one of the most pleasant cables that I’ve used in practice. It’s easy to unwind, rarely kinks, and the microphonics are well-controlled. In terms of build quality, it’s also a winner with well-machined hardware and attention to detail in the glue’s application. Of course, I should expect nothing less for such an expensive cable but, as I’ve harped on in the past, I would say that the majority of expensive cables I’ve handled are a miss on these points.

The Duality itself sports a slightly industrial design with intersecting circles on the faceplate and a sandblasted, 6061 aluminum shell. The shell ergonomics are clearly inspired by the Subtonic Storm’s shells. They feature shorter, stouter nozzles juxtaposed to a larger shell but, overall, seem like they’ve been scaled down by, say, ~20% relative to the Storm’s shells. Given that I already find the Storm to be fairly comfortable despite its large size, I find the Duality to be very comfortable and I can wear them for hours on end.

There are multiple, thoughtful considerations that stand out to me about the Duality’s construction. First is an integrated switch system that’s used to swap between the Bass/Balanced tunings. Unlike many IEMs that sport switches, the Duality’s switches are not plastic, but metal, and they’re easily actuated with just a fingernail. Second, the Duality has recessed 2-pin connectors which are more robust than standard 2-pin connectors. And finally, the Duality seems to vent the dynamic drivers through a clever slit that sits next to the 2-pin connectors.

Basically, a major selling point of the Duality for me is the efforts that have clearly been put into the user-experience. A lot of flagship IEMs chase pure sound quality above all-else; this was also my philosophy when I first entered the hobby. But as the years have gone by, I’ve realized that comfort and practicality are equally important, and they’re factors that dictate whether I listen to an IEM in the long-run. The Duality feels like an IEM that can stand up to the rigors of everyday life and that you don’t need to baby from the comforts of your home.

Sound Analysis

The Duality has two distinct tunings at the flick of its switches: Bass and Balanced. Additionally, there is an included impedance adapter that will boost the bass marginally on either of these settings but I didn’t use this for most of my listening.

The Balanced tuning reminds me a lot of the Elysian Diva’s tuning if it was built off of dynamic drivers. I say this in the sense that the Balanced tuning is sub-bass focused and with a healthy amount of upper-midrange presence. However, the bass is mostly concentrated under 100Hz, and I find myself cranking the volume to hear more of it. This, in turn, makes the Balanced tuning slightly shouty. Using the impedance adapter on this setting might alleviate some of this issue. Comparatively, the Diva’s tuning is more conducive to louder volumes due to extra presence in the 3-4kHz region which serves to balance the elevated pinna notch.

You do get a boost in clarity with the Balanced tuning, and it’s by no means a bad tuning. It’s also pretty versatile pending slight tolerance for more upper-midrange presence. But my clear preference is for the Bass tuning, and it’s what I’ll be basing my comments on going forward.

That in mind, the calling card of the Duality is its gargantuan bass response. It’s more or less akin to being in a car with the bass boosted to 11. Notes have huge amounts of ‘boom’ to them when they hit; however, the way they bloom in the decay is quicker than you’d expect. I have to admit: it’s tough to measure the Duality by conventional metrics because I don’t necessarily find this to be the most ‘slammy’ or well-textured bass response. That’s something that simply happens with this much bass quantity. Despite this, the Duality still produces bass that I find to be high-quality; it resolves quick bass lines neatly and there's a sense of rigidness to transient attack that reminds me of bass out of a full-size subwoofer.

I’ve observed that the music you listen to does make an appreciable difference on the Duality. If your music is inherently light on bass, or doesn’t benefit from modern mastering, my experience is that the Duality can sound too dull. But put on some Hip-Hop like Filthy The Kid’s “5th Ave” or Kendrick Lamar’s “hey now”, and you have a very satisfying combination with the Duality.

In this vein, I would describe the Duality’s bass as one that’s putting on a show: it’s not an accurate one, or even one that will appeal to everyone, but it’s a highly entertaining, curated one for the right audience. If you want something with more conventionally great bass (which comes with less quantity), you’d be looking at something like the 64A Tia Trio or Sennheiser IE900 instead.

Moving upwards to the Duality’s midrange, there are some subtle tuning liberties that become more evident on the Balanced tuning, such as a slight indentation to the pinna gain at ~1kHz and slightly more energy at the notch (the 3kHz region). But on the Bass mode, these adjustments come across quite neutral and I’d describe the Duality’s midrange as being simply uncolored.

Moving into the treble, I have good things to say about the Duality. It leans more mellow in that 5-6kHz is more reserved. 5-15kHz is relatively level, then there’s some softness past 15kHz, but not to the point where it sounds like it’s decidedly rolled-off. This is an area in which I felt the Singularity struggled; the addition of a second dynamic driver for the highs is clearly a boon with the Duality.

Something I have to emphasize is just how smooth, inoffensive this treble response is. Usually, what stops us from listening louder is not necessarily sheer volume and we can listen to bass quite loud. But treble is a different story; many IEMs exhibit peaks that can be harsh/fatiguing at louder volumes. Basically, the tuning ethos with the Duality is oriented around facilitating louder volumes and letting the bass shine through by maintaining a natural, smooth treble response.

Presentation

I like the presentation of the Duality a lot, and it mostly comes down to how natural and effortless it sounds. Leading edges on the Duality are not conventionally sharp. They have more of a brushed quality to them - not rigid like I’d hear from most BA setups but also not mushy like I hear with most dynamic drivers.

Likewise, the staging of the Duality is actually very good and doesn’t run into the ‘wall’ that most dynamic driver configurations seem to be confined by. It’s not in the sense that instruments ‘float’ around the stage - which I find would require more upper-treble - but that the placement of backing instruments seems to extend effortlessly to the extremes of the stage.

Intuitively, I would point to this being a combination of the Duality’s unique pinna gain profile and the smooth treble response. There are recessions to the otherwise aggressive pinna gain that are so subtle that they aren’t directly noticeable with core musical content but that are realized with backing instruments. Then the smooth treble response aids in the accurate, natural placement of instruments, similar to what I hear on the 7th Acoustics Supernova. Again, this is just supposition; in any event, the Duality makes clear that it’s no normal DD IEM in this regard.

Collectively, these features 1) allow for elevated listening volume and 2) prevent detail in the midrange and treble from being overshadowed. I wouldn’t say the Duality has great technicalities overall (especially for pure note sharpness) but it’s sufficient for daily-driver material and compensates neatly in terms of timbre and layering. These capabilities, of course, scale-up when listening on the Balanced setting too.

Comparisons

The Symphonium Titan represents an interesting point of comparison given that the manufacturers have often worked together closely. Head-to-head, the Titan actually has noticeably sharper note edges and more clarity. However, in terms of which one sounds more refined, and the one I’d want for long-term listening, I’d lean towards the Duality (although it’s certainly not on the same level, value-wise, as the Titan). The Duality’s presentation seems more natural to me, likely owing to its smoother treble response.

The FatFreq IEMs are other good points of comparison. Again, I think that the FatFreq IEMs like the Maestro SE might have conventionally better note sharpness just due to having more aggressive treble responses. However, in this case, I don’t find their bass to be quite as refined. The Duality, generally speaking, has more sub-bass focus and more quantity in those lowest registers (with the exception of the Scarlett Mini but even that has quite a lot more mid-bass).

Indeed, a lot of what sets the Duality apart from these other IEMs is an overarching sense of refinement to its sound. Everything about its presentation syncs together and sounds whole. It has a clear tuning ethos and doesn’t try to be something that it isn’t - at least on the Bass mode. As far as I’m concerned, this is something that may or may not matter depending on listening experience. When I first started listening to IEMs five years ago, I might have just focused on the Duality for its bass response instead of appreciating the bigger picture.

This is not to say that seeking refinement and coherency is categorically better, though. Take IEMs like the Elysian Annihilator 2023 and 64 Audio U4s. Admittedly, these are IEMs that do not have the most coherent presentations. I can recognize this; yet, these remain two of my favorite IEMs because of their technical merits that (usually) would otherwise not be possible. It’s really a matter of different strokes for different folks.

The Bottom Line

Ultimately, the Duality is a luxury IEM that’s clearly catered toward an audience with deep pockets and an existing collection of IEMs. You can’t expect it to be 3x better than its contemporaries which offer a similar basshead experience - that’s just how diminishing returns work. What you can expect, however, is that it does things none of the aforementioned contemporaries can. It’s an IEM that refines the ‘neutral with insane bass quantity’ ethos to the highest degree I’ve heard yet. It’s the complete package - endgame material - if this type of tuning is your jam, and then possibly more with its tuning toggle.