In our bonus feature today, Kurt reviews the NF ACOUS NM20, a 2nd generation single dynamic driver IEM based on the company’s popular NM2. It is priced at $118.99.
Disclaimer: This sample was sent to me in exchange for my honest opinion. Headfonics is an independent website with no affiliate links or status. I thank NF ACOUS for their support.
Click here to learn more about the NF ACOUS products we have previously reviewed on Headfonics.
This post follows our current scoring guidelines which you can read in more detail here.
NF ACOUS began creating IEMs for stage performers and musicians in 2014 when it operated under the NF Audio brand.
Over time, they’ve expanded their focus to cater to a wider range of audio enthusiasts while continuing with their craftsmanship and vision of creating a better acoustic experience for every scene.
Building on the NF ACOUS NM2 legacy, a beloved classic that sold over 100,000 units worldwide, the NM20 arrives as its successor with thoughtful upgrades. But can the NF ACOUS NM20 truly surpass the timeless charm of its predecessor?
Features
The NF ACOUS NM20 features a single dynamic driver setup, utilizing the MC2L-100P driver at its core.
This driver incorporates Neodymium magnets, a Beryllium-plated diaphragm, and dual magnetic circuits for enhanced stability and precision.
It also includes a high-precision integrated tuning PCB, which ensures consistent and reliable performance. Complementing this is a dual acoustic chamber system that helps manage airflow and optimize sound delivery.
The NM20 uses NF ACOUS’ patented “Clutter Trap” technology to further refine its output. This system reduces reflected sound using five damping nets and two tuning sponges while maintaining an ideal air pressure balance between the front and rear chambers.
Design
The NF ACOUS NM20 features a transparent polycarbonate shell paired with CNC-machined aluminum faceplates. The faceplates have a frosted metallic finish with the NF ACOUS logo etched at the center of each earpiece.
The shell is a translucent blue color, allowing partial visibility of the internal components and driver layout. Its smooth, curved profile has no visible vents on either the faceplate or shell.
On the outer side of the shell, the “NM20 Monitor” is printed in white text, and positioned near the upper edge. The nozzle is made of metal, with a mesh grille at the tip and no visible lip to secure ear tips firmly.
A 0.75mm 2-pin socket is placed at the top of the shell, which is slightly unconventional compared to the standard 0.78mm size found in most cables.
Despite being lightweight, the shell feels cheap both in hand and when worn, lacking a premium feel and experience.
Comfort & Isolation
The NF ACOUS NM20’s comfort proves excellent with its lightweight build that prevents any tugging or fatigue during long listening sessions.
The polycarbonate shell maintains a consistent temperature against the skin, unlike metal IEMs that absorb heat or cold.
The smooth, rounded design avoids any sharp edges or corners that make it ideal for side sleeping. The shell nestles comfortably in the ear without any pressure points, even during extended wear.
The isolation proves to be the weakest aspect of the NM20’s design. External noise penetrates through regardless of tip selection, disrupting the intended listening experience.
Tips
A single set of white high-quality silicone ear tips comes out of the box with the NF ACOUS NM20. Unlike the standard black silicone tips often included with IEMs, these have a more premium feel and a notable impact on the overall sound quality.
Out of the box, the ear tips have a powdery texture, adding a soft and grippy feel for a secure fit. This helps maintain a consistent seal without slipping during extended listening sessions.
Unlike other IEMs that try to include foam tips, the NM20 only comes with this single set. Fortunately, these tips don’t negatively affect the sound and instead help control and contain the bass, keeping it tight and well-behaved.
Stock Cable
The NF ACOUS NM20 comes with a lightweight braided cable in a clean silver finish. Its design makes it easy to carry and wear without any strain, but it tangles far too easily during storage or daily use.
The connectors and 3.5mm jack are made of metal, with the NF ACOUS branding printed on the termination. There’s also a cable divider with the NF ACOUS logo etched into it plus a chin slider, adding a small touch of style.
In terms of design, the cable keeps things simple with its clean silver braid and minimal branding. While it lacks a 4.4mm option, the included 6.35mm adapter offers added flexibility for connecting to stage or studio equipment.
Packaging & Accessories
The unboxing experience of the NF ACOUS NM20 begins with a sleek black box featuring a glossy image of the IEMs on the front. The bold “NM20” text stands out, with “Pro” highlighted to emphasize its status as part of NF ACOUS’ Professional Series lineup.
Turning the box around reveals key details about the NM20, including its shell material, driver technology, and cable specifications. The sides also feature an image of a rock star mid-performance, reinforcing its focus on stage performers and live musicians.
Inside, a book-like black box with a matte finish and subtle NF ACOUS branding is revealed. Opening it greets you with a guidebook on the left and a circular disc-like holder in the center, securely displaying the NM20 IEMs with NF ACOUS’s logo prominently printed.
Below the guidebook, there’s a compact black storage case with a textured surface, a red pull tab, and the NF ACOUS logo at the center. A 6.35mm adapter sits neatly beside it, offering extended compatibility for stage and studio setups.
Underneath the circular holder, the IEMs are carefully placed alongside a set of silicone ear tips in XS, S, M, and L sizes. The braided stock cable is coiled nearby, completing the package with a clean and organized layout.
Sound Impressions
The following sound impressions were completed using a mix of the Heartfield R1 and Colorfly CDA-M2 dongle DACs for source and amplification.
Bass
Despite delivering a sub-bass presence that feels adequate, the NF ACOUS NM20 lacks weight in most areas of the bass. While there’s some rumble, the punch feels more like a baby’s punch rather than a satisfying hit.
When it comes to bass quality, it doesn’t do much better. There’s an audible loss in texture and detail, and the lack of quantity doesn’t make up for this shortfall either.
It’s not tuned for bassheads, nor does it appeal to those who prefer a more refined low-end experience. Instead, it sits awkwardly in the middle, not fully committing to either side.
This bass tuning seems more focused on stage monitoring or mixing purposes, where a leaner bass response helps prevent muddiness. But for casual listening, it doesn’t deliver the kind of engaging energy you’d expect from a dynamic driver IEM.
Mids
Thin-sounding mids instantly show their presence with the NF ACOUS NM20, leaving both male and female vocals without much weight. It lacks forwardness in the presentation, making them feel like they’re missing warmth and fullness.
While the mids are undeniably clean and free from muddiness, the thinness takes away from their natural character. The vocals sound a bit hollow like they’re stretched too thin across the frequency range.
In the upper mids, there’s a sharpness that can make certain vocals feel shrill. Instead of adding clarity, this boost just ends up making the thinness stand out even more.
Adding to this, vocals have an overly breathy quality that makes them sound exaggerated and unnatural. This breathiness emphasizes the thinness even more, leaving the mids feeling unbalanced and fatiguing over time.
Instruments in the midrange suffer from similar issues, lacking the body and texture needed to sound convincing. Acoustic guitars and pianos, for example, sound artificial and overly bright, missing the organic tone they’re supposed to have.
The brightness becomes more obvious with female vocals and instruments like electric guitars. It adds an artificial edge that makes the mids sound a little too sharp for comfort.
Treble
The treble on the NF ACOUS NM20 has a noticeable issue with sibilance, especially with female vocals. There’s a sharpness and edginess in the upper registers that can make certain tracks sound harsh and uncomfortable.
On a brighter note, the detail retrieval here is pretty good. Subtle nuances and small microdetails can be picked up, even if they got artificially boosted to get there.
Instruments in the treble range don’t fare as well, though. Guitars and pianos lose their natural bite and energy, sounding dull and lacking their usual spark.
This balance between boosted clarity and a lack of liveliness leaves the treble in an awkward spot. You can a good amount of detail, but the overall presentation feels flat and lifeless.
Staging & Dynamics
The NF ACOUS NM20 delivers a soundstage that feels pretty average, with not much depth or height to make things stand out. Everything feels a bit cramped like the sounds are all gathered in the same space.
Imaging does a decent job, though. You can tell where sounds are coming from, but the limited width keeps them from fully spreading out and creating an open feel.
Dynamics are where things start to feel uneven. The treble tends to dominate, leaving the bass and mids sounding quieter and less impactful in comparison.
Separation isn’t the cleanest either, especially in busy tracks. The mids and treble often overlap, making it harder to pick apart individual elements without things feeling messy.
Click on page 2 below for my recommended pairings and selected comparisons.
