NF ACOUS NM20 Review

• Model: NM20
• Dimensions: 150 × 132 × 83mm
• Package Weight: 300g
• Driver: Dynamic Driver
• Cable: 0.78mm dual pin 5N OFC
• Sensitivity: 108 dB / mW
• Impedance: 32Ω
• Sound Insulation: 25dB
• Frequency Response: 9-40kHz
• Distortion: < 1%
• Max SPL: 125dB
• Connector: 3.5mm
• Price: $118.99

Sound

Fundamentally, Harman’s inspiration is evident. However, a mid-bass bump and small lower-treble peak create a U-shaped character. Nevertheless, the tonality remains very pleasant. Lows are full yet controlled and super punchy, setting the foundation for an inviting light-warm midrange tonality. Though slightly laid-back, the vocals retain focus with a clear and natural voice. Meanwhile, the top-end is crisp and energetic.

The focus is centered around the foreground preceding a darker background and subsequent boost in top-octave sparkle. Such tuning is ideal for my preferences as it brings micro-details to the fore without any overt brightness or glare. As the contrast is slightly higher, I would characterize the NM20 as a more engaging linear, and coherent earphone. However, as it lacks any midrange intensity, it remains suitable for long-term listening. Altogether, it is a beautifully tuned signature that’s engaging but not pushed too far to alienate lovers of balance.

Lows

The NM20 has a hefty, well-weighted low-end tuned for engagement over linearity and balance. Thankfully, the bump is tasteful and doesn’t swing too far into the bass-head territory; this earphone will be enjoyed by those wanting balance while satisfying listeners wanting a bit more oomph too. Sub-bass extension is excellent, providing a hearty slam reaffirmed by palpable pressure at the very bottom. Rumble is well-defined and bass retains great definition into the sub-audible, very satisfying for electronic and drums.

Mid-bass sits at the forefront, with a moderate hump. In turn, the bass is full and presented with a warm tone. It tapers off smoothly into a recessed lower-midrange thereafter to avoid midrange coloration and excessive warmth. While notes are bold and enlarged, due to the progressive tuning and only modest mid-bass emphasis, bloat and muddiness are absent.

That said, detail retrieval is well above average. The NM20’s note presentation is highly controlled, aided by a rigid driver and strong magnet structure. Decay is on the faster side for dynamic drivers and attack is aggressive too, helping to counterbalance the increased fullness. Dynamics are on the higher side as a result, though subjectively would have been aided by a cleaner tuning.

In particular, the NM20 possesses a very hard-hitting response, both in the mid and sub-bass, but misses some tightness and definition in the mid-bass. While detail retrieval is a good performer, the reduced separation means this isn’t the defining trait of this earphone. Rather it is the impressive depth, power, and texture on display that operate without upsetting the overall balance.

Mids

With a recessed lower midrange and progressive rise to 2.3kHz prominence for pinna gain, the NM20 retains a mostly natural voicing and avoids excessive tonal coloration too. It remains a colored earphone, with a light warm tone that counterbalances a slight reduction in midrange note body. Despite the emphasis appearing large in measurement, the NM20 sounds a little laid-back in the midrange with its bass and treble tending to draw more focus.

Subjectively, I find this contributes to a slightly easier listening experience, as it avoids the intensity and strain. The progressive tuning does mean the earphone retains a very natural voicing, vocals sit just in front of midrange instruments but aren’t peaky nor sibilant. If I had to critique them, they are a little raspy and over-articulated, a result of a subsequent 6kHz peak with only a small dip in between.

However, never is the NM20 pushed into the realm of sharpness to my ears, especially when considering the slightly laid-back midrange position. The added warmth too makes this a more inviting listen to your usual reference earphone. It is a little more forgiving but also isn’t colored nearly to the extent that muffle and veil become an issue; if anything, the NM20 is a clarity-enhanced earphone due to its articulate nature.

The NM20 is easy to enjoy with no notable weak points. Perhaps those sensitive to treble may find it a little bright leaning with its slight raspiness and slight thinness, but the lack of forwardness is a tasteful execution. The net result is a midrange that sounds natural yet clear with a hint of additional warmth augmented by enhanced note definition. While not perfectly even, it is perfectly enjoyable.

Highs

Similar to the midrange, the NM20 injects a little extra energy and zing here without overstepping boundaries. It is defined mostly by a small 6kHz peak in equal measure to the upper-midrange, albeit, due to the nature of the human hearing, it appears slightly forward by comparison. Relative to the more linear earphones I’ve been enjoying lately, the NM20 is crisper, sharper, and more energetic. It has great foreground detail retrieval owing to its clean transient response which enhances separation.

Subjectively, some fine detail is overshadowed due to the bright upper-mid set to bright lower treble which could do with a little more damping in the 5kHz region, albeit treble itself is clean and clear. While note attack is keen, decay is a little quick, exacerbated by the dive into the middle-treble trough. Alongside the thinner note body, this saps some texture and shimmer, increasing the perception of thinness.

Regardless, the NM20 is nicely detailed and has an awesome contrast to its dark, immaculately clean background. This draws further focus to the lower treble, minimizing glare, and ringing and preventing over-brightness. As with many earphones of this nature, a small upper-treble lift aids layering and headroom in the absence of middle-treble presence but don’t expect a lot of air as a result, it sounds quite muted. While the extension isn’t uncharacteristic of the price range, it isn’t at all lacking, producing a pleasing amount of energy and background detail.

There still isn’t much sparkle and micro-detail at the very top that pricier models with this style of tuning may provide. However, the NM20 does provide a nice sense of space without feeling sparse and its layers are nicely defined, with even smaller details in the background. While it doesn’t highlight said details, it provides enough nuance to achieve a good sense of dimension and depth that is far from a given at this price point.

Soundstage

With good treble extension, the NM20 sews its presentation together well with a nice, spacious soundstage. It stretches beyond the head with great width and has good but not sensational depth, forming an oval presentation. Imaging performance is good but not great.

The NM20 has good coherence and sharp positioning across its lateral plane. Directional cues are sharp and layering also performs at a high standard, being defined and delineated. However, the center image could do with more sharpness, being a bit diffuse and pushed laterally. Coronal positioning is nothing special.

vs NA2+

Compared to NA2+ which I reviewed earlier, the new Nm20 has more low-end bump including sub and mid-bass and also mid treble bump which gives more detail retrivel to the end sound.

Sum-Up

The NF ACOUS NM20 is a good-looking and well-constructed IEM that has a sound signature offering an impressively versatile tonality with a natural, inviting midrange and a dynamic super punchy bass response. A general appeal that does well with almost any music genre. These IEMs sound as good as they look.

My only nitpicking is the stock cable. NF ACOUS should start including more attractive cables in the box because the contenders are way ahead in this regard.