The debate is popular and still going all through the audiophile community about the sound change with different cables. Some say it's true, some say it's psychological. Even they are divided into two groups about this matter—believer and non-believer... ha ha ha ha ha! But is there any science behind this? I think so. It's all depending on the material used to build the cable.
NMD Audio Neptune Review
NMD AUDIO was kind enough to send me the Neptune cable to review. I am not affiliated with NMD AUDIO, and of course, I was not asked for any copy-checking before publishing. All opinions shared in this ‘NMD Audio Neptune review’ are my subjective thoughts.
One thing more: The review is based on my personal experience and what I hear using different sources. Your experience may vary because of personal preference and physical differences like the shape & depth of the ear canal.
For your personal purchase, checkout GEEK MART or NMD AUDIO for their fantastic products and promotions (non-affiliated link).
Copper is slower in signal transmission compared to silver. For that reason, copper cables tend to deliver warm and rich sound signatures with fewer details and a softer treble response. On the other hand, silver, being better conductors, provides a brighter and more detailed sound profile with good treble extension and micro details. The most popular type of cable is silver-plated copper, or hybrid cables, you may say. They generally offer a balanced signature with the warmth of copper and the clarity from silver. These characteristics make hybrid cables versatile for different IEMs, regardless of their tuning.
Keep in mind that perceived changes in sound depend mainly on personal tune preference and the synergy between the cable and IEM. If you connect an analytical IEM with an analytical source using a pure copper cable, don’t expect a warm sound from that set-up, and on the other hand, a warm source paired with a warm IEM through pure silver cable can’t give you the ultimate detailed sound either! The true change in sound is literally subtle and minimal. But to me, it’s audible.
Let’s come to the point of my review today, the NMD Audio Neptune cable. I think you already know about NMD Audio, which is a Hong Kong-based company specialized in high-quality audio products, particularly upgrade cables for IEMs. The brand has gained recognition for its innovative designs and premium materials & looks. They offer a diverse lineup, ranging from the entry-level “Nova” series to premium models like “Mist and “Sakura,” each tailored to different sound profiles and price points. The cable I’m gonna review today falls in between their entry-level and premium, with a price tag of USD 243.
First thing first, the packaging. As they sent us two cables for review purposes, they didn’t send them with their official packaging. It came in a beautiful leather pouch with the company branding. The pouch is practical and usable; you can carry the cable with your IEMs, whether they are fat or slim! The leather-made cable organizer is also beautiful and has a clip button instead of Velcros. It’s a medium-sized package with a good touch of attention to the details.
Let’s take a look at the build & design. The NMD Audio Neptune is a comparatively thick cable with a fabric muffler on, which feels robust. The color combination is awesome; the mix of light and deep blue is so fantastic, and it will catch your eyes in no time. The 4.4mm jack is gold plated, and the 0.78mm connectors are too. The Jack terminal, cable splitter, chin slider, and connectors are very well built, and each has a good low-cut grip to handle them easily even with sweaty hands. The terminal and the y-splitter have branding on them, while the connectors have R & L markings. The ear hooks are with a memory plastic coat, which sits over the ear perfectly.
Comfort-wise, it’s a good one. Though it’s a thicker one and weighs more than your regular cables, it didn’t feel uncomfortable. I have NiceHCK MixPP in my collection, which is thicker than NMD Audio Neptune, so it’s not the ‘thickest’ one to me. I can wear it for 1-2 hours straight. But in longer listening sessions (like 4-5 hours), it creates a bit of an uncomfortable feeling, especially over the ears. When you relaxly lay or sit on your sofa for your listening, it won’t create any microphonics with your movement. But if you are walking or jogging wearing your IEM with this cable, the microphonics are audible. Turn up the volume a little bit, and it won’t bother you.
Now let’s come to the materials used in the Neptune, which play the main role in delivering the sound quality. As per NMD Audio, this cable contains “Cryogenically treated 6N OCC single-crystal copper & Cryogenically treated 6N OCC single-crystal & cryogenically treated 6N OCC silver-plated copper.” In general, the cryogenic treatment process further refines the material properties, purportedly improving signal transmission stability and reducing electrical resistance. This can present the sound with tighter bass, more precise imaging, and an overall smoother sound signature.
Here comes the main part, the sound signature. NMD Audio claimed that ‘Naptune’ will deliver a balanced sound with moderate bass depth, accurate drum positioning, and airy female vocals that extend into high frequencies. Wide and expansive soundstage with both horizontal and vertical depth, providing accurate instrument positioning and layering. Moreover, it will enhance the performance of string instruments. Is the claim true in a real-world scenario, or is it just a marketing gimmick? To understand the whole sound characteristics of Neptune, I paired it with dozens of IEMs in my collection. Let’s discuss my experience.
I will start with my recent favorite IEM, the AFUL P5+2. The common complaint about this set is its planar & BA timber in upper frequencies. True that, but with the stock cable. It dramatically disappeared with the Neptune! And with my most favorite IEMs from Aful, the P5 and MagicOne also delivered a tad bit of warmth in the bass area with this cable. This is fantastic! But the Explorer doesn’t pair very well with it; I donno why, but I didn’t enjoy the sound it delivered.
With my beloved Hidizs MP145, it delivers the true sound signature of the IEM with different tuning nozzels but with a bit of less treble energy, especially with the rose gold nozzle. While pairing it with Ikko OH10 and 10S, which have some BA timber in female vocals, this NMD Audio Neptune handled it just right and almost no BA timber. I didn’t hear any audible differences in Moondrop Aria OG, Aria 2, SeeAudio Rinko. But my good ol’ pal Moondrop Lan finds a new life with it; the sound is so lush and musical, and I was amazed. And the Kinera Celest Phoenixcall also sounds a bit warm, with an audible amount of smooth warmth in the midrange.
Lastly, here comes my new Kinera Vendardy, which I’ve been testing for the last couple of days. I found the original vocal presentation, both male & female, is a bit thinner and more forward than my liking. Using the Neptune cable eased the problem, and now the vocal sounds a bit fuller and warmer, but with good clarity.
To be very honest, I didn’t find any audible change in soundstage. The instrument separation is good, though. That doesn’t mean you will pair this cable with any IEM that has a congested instrument presentation and will expect this cable to make it open! That’s not gonna happen. The AMD Audio Neptune mostly makes the lower frequencies warm without secrificing the clarity in midrange or upper frequencies. Due to the good separation ability, it also enhances vocal clarity. And it can solve some problematic ‘planar/BA timbers,’ though not the whole, but a bit of it, which is audibly satisfying.
Finally, what I can say is that the above experience is my personal, very personal. You may hear the difference or you may not; you may take it as just an upgrade cable or as a cable with ‘characteristics.’ Experience varies person to person, like it varies when it comes to the sound signature of audio gear. But if you have the budget to spare and are interested in buying this cable, just give it a try. Remember, it won’t dramatically change the sound of your IEM, or you may have bitter experience with a bad pairing.
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