NF ACOUS NM25 Review: Can An IEM Be Too Accurate?

Don't forget to share if you found it helpful!

Greetings mate and Welcome aboard!

Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions, so…

Video Review

When you hear the word “monitor,” certain things should immediately come to mind. Neutrality is perhaps the most important consideration, as you’ll want something that doesn’t unnecessarily hype frequencies, overly boost the bass, and generally sound like a product made for enjoyment.

The NF ACOUS embraces this idea, opting for a relatively uncolored presentation and positioning itself as a strong contender in the realm of precision-focused in-ear monitors.

In this review, we’ll take a closer look at the NM25’s build quality, comfort, accessories, and most importantly, its sound signature to determine whether it lives up to its promise as a true reference monitor.

Verdict

• Sound: 8.0
• Build: 10
• Comfort: 8.7
• Value: 9.0

Pros

• Very neutral tuning
• Excellent resolution
• Great imaging
• Built well
• Bass tips make them better

Cons

• Lean note weight with medium/small tips
• May sound clinical
• Not for bass lovers
• Can sound a bit papery with dry Timbre

Best For

• Mixing
• Mastering
• Reference Listening

Avoid If

• You want warmth
• You prefer V-shaped tuning
• You want a relaxed listen

If there’s a product that truly earns the IEM (In-Ear MONITOR) moniker, I think the NM25 is a strong candidate.

It doesn’t flatter recordings at all or add warmth when none exists. Poorly mixed tracks, excessive compression, and a lack of dynamics all become painfully apparent, almost within seconds of listening.

I found myself skipping quite a few songs just to get to a good one. Whether that’s a benefit or a drawback depends entirely on what you’re looking for.

If your goal is to hear exactly what went into the recording, it’s hard to beat the NM25. That said, the IEM’s somewhat papery timbre and bright, almost cold sound certainly contribute. So I think it’s a combination of a couple of things happening at once: exceptionally revealing tuning and a sound signature that does very little to smooth over imperfections.

Build Quality & Comfort

The handmade NM25 is comprised of a sterling silver artisan faceplate crafted via traditional jewelry lost-wax casting and hand-polished one by one.

Note: this version of the NM25 (The Ossuary Silver Edition) retains the same tuning as the original. The only difference is that NF ACOUS collaborated with an independent silver accessory brand, so the faceplate is made of 925 sterling silver.

Its striking design is likely the first thing you’ll notice, resembling something Nathan Drake would use to listen to music on one of his many expeditions to find lost treasure while almost dying a lot.

There’s some interesting-looking artwork surrounding a very well-done skull, coming in silver with a gold border.

The 5N silver-plated, oxygen-free copper cable is a braided four-core and terminates in a standard 0.78mm 2-pin connector with a 3.5mm jack at the business end. NF ACOUS includes a unique-looking 6.35mm adapter, adorned in silver, which provides a nice contrast to the mostly gold adapters I have lying around.

Overall, it’s a solidly built IEM, and I have no complaints.

The buds themselves feel nice in your hand, just thicc enough to make it feel like you’ve purchased something entirely worthwhile.

Putting them on with the braided cable also feels super official, but in reality, you’re just listening to music so let’s pump the brakes, shall we? 😛

Comfort

Fitment is about what you’d expect, and since you’ll be wrapping the cables around your ears, make sure the connections are correct. There’s a nifty instruction guide that comes in handy upon first listen.

Comfort is just fine and gets the job done. I don’t typically find any IEM to be superb in this regard, so take that for what it’s worth. Take it with a grain of salt if you need to. It should be noted that I haven’t had any issues with having to adjust them (yet), so that’s always a positive.

Accessories

It’s a relatively simple package, containing a few sets of tips, the user guide, the earbuds, and a beautiful carrying case.

Isolation is very good, and because they’re marketed as monitors, it should be. You’ll hear very little outside noise provided the fit is good, and they do a good job of immersing you in the sound.

Speaking of, let’s discuss it.

Sound

• Playlist(s): Love Is Calling Part 2, Stay Sane, Hip-Hop 101 My Belle, & The New Beach Playlist For Guys Still Named Brian 2
• My Music: Here!
• Source(s): FLAC, Lossless
• DAC/Amps Used: FiiO K7, Universal Audio Volt 2
• Eartips used for evaluation: Medium/Standard

Before we start

For what it’s worth, I did most of my listening with the medium (standard) tips. Personally, I wouldn’t recommend the XS or small tips, as they will make an already bright, somewhat brash sound signature feel even more pronounced. The large tips are what you’ll want to go for here. They fit me well and provided a fuller, more balanced presentation, making them worth considering if you found the stock tuning a bit too aggressive, as I did.

I found this to be the case, but the overall sound is still more or less the same.

Let’s dive in…

Bass

From the get-go, it’s clear that the NM25 is honest, both in terms of how it sounds and how it’s marketed. This is not an IEM tuned to impress with a boosted bass or artificially colored profile, kind of.

It opts for a largely neutral presentation, but please keep in mind that there’s quite a bit of upper mid-range energy around 2-4kHz, which pushes vocals and transients forward. This can sometimes result in a shouty-ish character, and that, coupled with the high treble energy, can contribute to that papery, almost brittle-ish flavor I discussed earlier.

Despite the bass looking fairly boosted in graphs, it doesn’t really sound like that when you’re listening. I think part of this has to do with the upper mid and treble energy standing out more prominently, in effect shifting attention away from the low end.

That said, bass notes feel and sound fairly low-profile and unassuming, favoring speed and control over weight and slam.

However, a lot of this depends on the track. For instance, Kraak & Smaak, IVAR – “In Plain Sight“ provides some tasteful thump, but it never gets out of line and sounds quite delightful.

Mid-Range & Treble

I guess a small concern I have is, again, the mid-range and treble. It almost feels like they’re forcing presence (mids) and air (treble), though it seems quite obvious that this is purposeful, especially given that they are meant to be monitors.

Sony’s MDR-7506 has received similar criticism over the years, and I can absolutely understand the sentiment.

That is to say that at times, the NM25 feels a bit metallic, artificial, and lacking body. This is ironic considering these boosts given are supposed to achieve the opposite, but the point remains.

Bad Sounds, Broods’ “Move Into Me” sounds fine, but comes off as a bit essier than I’d like, bordering on overly sharp and somewhat aggressive. This can result in listening fatigue after around 30-60 minutes.

Resolution

One positive byproduct of this type of sound is resolution.

Tiny artifacts, subtle whispers, hums, reverb tails, guitar string texture, and anything you may have missed with other inferior products will likely be revealed, in effect allowing you to highlight flaws in a mix and act accordingly.

Soundstage & Imaging

Soundstage is about average in my opinion, as I don’t really feel like these are very “out of my head.” This isn’t something I feel is mandatory for monitoring, but it does help. That said, it’s not a dealbreaker in this case.

It’s mostly a headwidth sound, with predictable height and depth. Occasionally, you may notice something out of the ordinary inside the stage, which contributes to a more immersive experience, but it isn’t the norm as it is with, say, an AKG K702. It’s more of an exception.

Thankfully, instrument placement is fairly precise and intentional, sounds are pinpointed well, and there’s good separation.

A good example of this is on Xavier Omar’s “Blind Man.” There’s the main vocal panned right, and a gruffer, slightly quieter vocal on the left that complements nicely. The NM25 brings this out better than I expected and highlights the juxtaposition quite well. Think of this sound as very clean and precise while also being quite in your face about it.

Dynamics & Timbre

Music mostly has punch, but again, it can feel like it’s jumping out at you a bit much rather than sounding natural. Again, these are monitors, so I understand why they went in this direction, but raising the volume can exacerbate these issues. 50 Cent & Robin Thicke’s “Follow My Lead” is a good example of the mids and treble kind of overpowering the track, leaving the bass sounding comparatively restrained and less impactful than it probably should be.

Timbre

That papery timbre remains apparent throughout much of the listening experience. It’s not necessarily distracting, but it does lend certain vocals and instruments a slightly dry, artificial quality that prevents the presentation from sounding completely lifelike.

Attack, Sustain, Decay, & Release

The NM25’s note envelope is on the quicker side.

Attacks are crisp and immediate, while decay and release happen fairly quickly, preventing notes from lingering longer than necessary.

This contributes to the IEM’s excellent sense of clarity and resolution, but it also reinforces its lean, clinical presentation.

The tradeoff is that notes don’t carry much weight or bloom. Instead of sounding rich and full-bodied, they tend to appear, deliver their information, and get out of the way.

For monitoring purposes, this approach works well, but those seeking a more natural and organic presentation may find it somewhat sterile.

So,

• Attack: Above average (fast)
• Sustain: Below average (notes don’t linger much)
• Decay: Fairly quick
• Release: Fairly quick

I personally enjoy slow decay and release times, as they contribute to that fuller, more natural, and more lifelike presentation, so I think they could have made this aspect of the NM25 stronger.

Genre Pairing

These seem to work well with most genres, and I primarily listen to Hip-Hop, Jazz, Classical, Indie/Rock, Dream Pop, Ambient, etc.

I’ve noticed that traditional Indie Rock falls a bit flat, but everything else I’ve listened to sounds decent enough.

Again, I keep coming back to that sense of brightness that’s hard to shake.

There are many examples, but one that stands out considerably is the high hat on D.I.T.C’s “Make ‘Em Proud.”

It’s pretty distracting (almost ruining the beat), but then I have to ask myself, wouldn’t this be a strength if I were trying to dissect a mix?

Yeah, probably.

This is why, at the end of the day, I can’t complain too much about what NF ACOUS is going for.

Final Verdict

Overall, I think NF ACOUS accomplished exactly what they set out to do.

The NM25 is one of the more honest IEMs I’ve heard, refusing to sugarcoat poor recordings or flatter mediocre mixes with added warmth or bass emphasis.

That said, honesty comes at a cost. The bright, clinical presentation, papery timbre, and lean note weight prevent it from being something I’d reach for when I simply want to listen to music. Instead, I found myself appreciating it more as a tool than as an escape.

If you’re producing, mixing, mastering, or simply want to hear every last detail in a recording, the NM25 is an excellent choice and lives up to its “monitor” designation.

If you’re after warmth, richness, and an effortlessly musical presentation, there are better options available.

In other words, the NM25 doesn’t try to make your music sound better. It attempts to tell you the truth! AND YOU CAN HANDLE THE TRUTH!!!

i’m sorry

Whether the truth is exactly what you’re looking for is a question only you can answer.

Pricing/Specs

Price: Check Amazon!

In The Box

NF ACOUS NM25

4 sets of tips (XS, Small, Medium, Large)

Braided Cable

1/4″ Adapter

Carrying Case

User Guide

Well that’s about it for today my friend! I hope you’ve enjoyed this NF ACOUS NM25 Review and came away with some valuable insight.

Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!

If you love what I do here and want to support the blog and channel in a more personal way, check me out on Patreon and discover all the value I have to offer you.

Just want to make a one-time donation? Click here. Your support is greatly appreciated and helps keep this site running!

What do you think of this sound signature as is? I would love to hear from you. Until next time…

All the best and God bless,

 

-Stu

Photo Gallery

Don't forget to share if you found it helpful!