Review: ddHiFi Nyx Pro

Sound impressions  

Before I begin, my usual disclaimer: cables have no ‘sound’ of their own. They can only transmit electrical signals to the IEM, and as such, cables can and do affect the sound profile of different IEMs to different degrees. How significant that effect will vary between different IEMs, but there are some ‘general traits’ specific to each cable that we can glean from pairing them with multiple IEMs.

With that out the way, one of the first sonic traits I notice with the Nyx Pro is a fuller, ever-so-slightly warmer tone that it seems to add with a subtle bass lift and denser midrange note weight. Voices that come across as thinner or slightly sandy with other cables tend to sound smoother and more organic with Nyx Pro, and yet don’t lose any detail with the change. 

I suspect these changes are also due to a slight smoothing off of transient treble edges, again not to the detriment of detail, and if anything, an increase in sparkle and microdetail up top. Bells and chimes, for example, have a more forward and distinct ‘ping’ sound to them, with more space to decay naturally into the background, and yet the ‘crash’ of metallic instruments like cymbals isn’t quite as hard-edged.

Madi Diaz has a beautifully warm and emotive voice on the opening track, Same Risk, from her new album Weird Faith. Comparing three different IEMs (see below) and three different cables with Nyx Pro, her breath sounds comparatively fuller, wetter and less ‘pockmarked’ with Nyx Pro, yet retains all the detail and, if anything, heightens the emotion in her vocalisation too. 

Similarly, Ethel Cain has a rasp to her voice, on most tracks off the brilliant Preacher’s Daughter album, that is often overemphasised by some IEMs, especially those with a sharper, peakier low-to-mid treble response. With Nyx Pro and every IEM I tested it with, that ‘dryness’ is moisturised, giving her vocals a smoother presentation without losing the detail or emotion.

I also notice that Nyx Pro pushes vocals, especially female vocals, slightly more forward, although they don’t come across as shouty. That suggests a more relaxed upper midrange, and a reduction of some lower treble energy too. Again, these changes are subtle, and switching sources and IEMs will vary these effects to some degree.

Lastly, Nyx Pro seems to add some bass volume, mostly to the sub regions but also higher up. Where the track calls for it there’s plenty of rumble, and I notice added physicality here compared to some other cables. 

That said, I find midbass punch to be a touch softened, not to the degree where I’m losing the sense of impact, but it’s not as ‘hard’ edged compared to cables with a tighter bass response. That’s not to say bass is loose or bloomy, on the contrary, but there’s a subtle padding to drum hits that lend that extra bit of organic resonance to tracks that would otherwise come off as harder and cooler.  

Technically, the tonal nuances noted above do have some perceptible impact on stage size, imaging and clarity. The most obvious change, for me, is the darker background, which makes details easier to hear despite the slight softening of coarser note edges. The darkness also creates a vaster stage, although on tracks with forward vocals, stage feels deeper than wider. 

One of my favourite characteristics of this cable is its ability to relax the sound while retaining details. Whether that’s from the added shielding or simply a combination of high-quality wire and soldering, if you want to add some meat to the bones of your IEMs, especially midrange note weight, while shaving off some treble edginess, it’s a good bet this cable might do the trick.

Conversely, if you prefer your microdetails coarser – or at least more explicit – and shudder at the thought of taking any edge off your treble notes, there are likely better alternatives to Nyx Pro, even in this price range. 

Select pairings

I tested Nyx Pro with three different IEMs, each of them with their own unique characteristics:

Bellos Audio X4 ($999, reviewed here). This was the IEM I kept coming back to with Nyx Pro, and the one where I most noticed its tonal effects. X4 has a warm-neutral tuning, with a slight bass bump that keeps the rest of the mostly linear and slightly drier tonal range in check. There’s a perceptible treble bump somewhere along the line that adds clarity, but also thins out the mids ever so slightly.

With Nyx Pro I hear a more defined sub bass, with heftier rumble, and not much divergence from an already healthy midbass response. The midrange is where the biggest differences are heard, with the fuller note weight and smoother, wetter vocals immediately notable. Treble is also smoothed out a touch, but also gets extra sparkle that brings out finer highlights and details in a very pleasant way. 

Staging on X4 can be flattish, with excellent stereo separation but not as much depth. Nyx Pro adds that depth by bringing some vocals forward, and creating more space behind the vocals. Stage width isn’t shrunk per se, but I do notice the depth more than the natural width of this IEM when paired with Nyx Pro. 

Empire Ears Legend X ($2,399). Still one of my top three IEMs, Legend X will forever hold a special place in my permanent IEM collection. The combination of its warm, bass-first tonality with a balanced and surprisingly (to some) wide and detailed technical presentation is almost the perfect storm for my sonic preferences. 

Unlike X4, Legend X inherently has fuller note weight and an organic midrange tone with superb clarity and resolution throughout. It also has a lower-to-mid treble emphasis that can, on occasion, step out from the crowd and make itself known. I usually pair Legend X with a top-tier cable like PW Audio’s The 1950s, which doubles down on the technical performance without over-sharpening the treble, giving it a more balanced W-shaped tonality in the process. 

With Nyx Pro, I notice the same soothing effect on vocals, again without any detail loss, although this is less obvious when compared to the change in X4. Bass retains its heft, but loses some slam, and while the excellent background separation and low noise helps the bass response, I tend to prefer a tighter, punchier sound down low with this particular IEM.

The biggest benefit with Nyx Pro is the treble response, which to my ears is gentler and less ‘biting’. If you love Legend X but find its treble too strident, this could be a good option to try, especially compared to its notoriously poor stock cable.   

FIR Audio Rn6 ($3,299, reviewed here). Similar to X4 in its overall tonal balance, FIR’s co-flagship, Radon 6, also has a musical-neutral presentation, propped up by a deliciously-textured Kinetic Bass driver at one end and a masterfully-tuned electrostat for the ultra-highs to add air and space. 

Where Rn6 occasionally suffers is note weight, especially compared to its fuller, fatter co-flagship Xe6. It also has a sharper upper midrange to treble rise that can sound a bit disjointed at times, especially compared to the smother bass and lower midrange. 

Nyx Pro gets straight down to work ‘fixing’ these shortcomings. It adds some weight to the midrange notes while relaxing upper midrange ‘shout’, and also subtly smooths out the lower treble for a more even response while adding sparkle further up the line. I generally recommend a cable with a fuller, smoother tone for Rn6, and Nyx Pro fits the bill perfectly. 

If you’re averse to buying cables with eyewatering price tags, even for expensive IEMs like these, Nyx Pro could be a more reasonable option that won’t blunt Rn6’s already-exceptional technical performance and, if anything, benefit its tonal cohesion. 

Select comparisons

Full disclosure: I didn’t spend hours and hours comparing Nyx Pro to every cable I have on hand, mostly because the majority of these cables cost multiple times more than Nyx Pro and are therefore, in my opinion, not in the same market segment. 

The cable I spent longest comparing to Nyx Pro – other than the stock cables on each of the IEMs above – is Eletech’s Raphael (reviewed here). Since Eletech and ddHiFi collaborated on Versa/Nyx Pin, and both cables retail for the same price, it was both a poetic and practical comparison to make. 

If you’ve read my Raphael review, you’ll know it’s one of my favourite cables at any price. It’s well made, beautifully designed, and very ergonomic, with a sound profile that makes it versatile with numerous IEMs. Previous to Nyx Pro I had Eletech paired primarily with the Bellos X4, and it’s the changes that Nyx Pro made with this IEM, and compared to Raphael, that most impressed me in the course of this review.

This is not a slight on Raphael at all. It’s a cable that does what it does so well, adding texture and tautness to bass, revealing extra nuance in the midrange – without altering note weight – and extending the treble range even further. Nyx Pro, in contrast, adds more emphasis to the sub bass while cushioning the midbass, adds midrange note weight, and relaxes the upper mids and treble that Raphael pushes slightly forward.

In fact, given their differences, I’d say these two cables are very complementary, and can cover most of the bases you’d have when considering upgrade cables from stock. They also won’t break the bank, relatively speaking, both being right on the edge of what I personally consider to be an excellent price/performance ratio and therefore great value.    

Continue to closing thoughts…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


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