NF Acous RA15 HiFi IEMs – Steady Flow Contralto Revealer
NF Acous RA15 is a $89 USD IEM and one of the last IEMS to be launched by the company before they will change the name to NF Acoustic or NF Acous, as they werew previously known as NF Audio, so today we will explore how this All-Metal Dual-Cavity IEM sounds like and how it might become your next music companion.
Introduction
NF Audio has rebranded recently to NF Acous and we should be using this name from now on, as the brand should be synonymous with quality, precision and great engineering, although most of the products I have in for review from them are entry-level IEMs. As an Amazon Influencer, I earn from qualifying purchases, and using the purchase links in my reviews helps me maintain this website and Youtube Channel. Huge thanks to Soundz for providing us with the sample for this review.
PROs – Compelling sound with a very good resolution, strong instrument separation and good layering, deep and powerful bass, and a sharp, distinctively bright treble. The upper midrange is sharp and has a strong revealing ability, which creates the feeling of a very detailed sound. Wearing comfort is excellent, build quality is reliable and the whole package is great for the price.
Cons – Only a soft transport pouch and no hard transport case, the tuning works best for commercial music and J-Rock / J-Pop, being too sharp for rock and metal.
Product Link
Amazon – https://amzn.to/48bfAAL
Aliexpress – https://s.click.aliexpress.com/e/_DCoDLhx
Build Quality/Aesthetics/Fit/Comfort
As NF Audio rebranded to NF Acous, the company wants to settle it once and for all that they are a quality over quantity company, so although the products I got in for review from them have the old NF Audio branding, the new NF Acous branding will service and support all products, from both the new branding, but also from the old branding. The marketing for RA15 is one of the hottest I’ve seen for an entry-level priced IEM, great graphics, minimal usage of AI and beautiful drawings.
Technically, RA15 is an IEM named MC2L-10M, with Dual Magnetic Circuit, Double Cavity Dynamic Driver, and it has both a warm and a bright tuning, with special replaceable tuning sound tubes, in the package coming with both a Brass sound tube and a Stainless Steel sound tube. The shell is made of all-metal, and the design is ergonomic, comfortable. There are high quality NF Acous MS42 silicone tips included in the package, and the cable of the RA15 is a 5N Oxygen Free Copper Silver-Plated Wire, with 3.5mm Single Ended connector on the jack end.
RA15 comes with an impedance of 32 OHMs, and a THD of 1%, having a maximum SPL of 125dB, and a Sensitivity of 108 dB/mW. The quoted passive noise isolation is around 25dB, while the weight of the IEMS + Cable is 160 Grams, although we generally do not measure gross weight, but the IEM shells weight, which I measured to be 9 grams for each IEM, which I qualify to be on the heavy side, thing which is to be expected given the metallic shells. The IEMs have a Recessed 2-Pin connector, which is not popular at the moment, but which is actually more resilient than the standard 2-Pin counterpart.
Between the two different sound tubes, the biggest difference is in how dampened the treble is, so I would recommend experimenting which you like best, although most of my testing and reviewing has been done with the Bright ones, the Stainless Steel Ones. Subjectively, RA15 is comfortable, the IEM shells are small, a bit heavy, but they have the right angles to be comfortable with my ears. The passive noise isolation is very good, and although with no music playing I can hear myself typing, the sound is dampened, and even with quiet music playing you won’t hear what’s happening around your room.
Happily, even with loud music playing, you will not leak your music to others, and RA15 is very good at isolating you from the background in general. The cable is very comfortable, only a tiny bit springy but does not conduct microphonic / handling noise, while the IEMS have no driver flex and no void, the wearing comfort is downright excellent.
Sound Quality
Pairings – To test the NF Acous Ra15 I have paired them with a collection of sources, including iBasso PB5 driven by iBasso D16, HIDIZD S8 Pro Robin, iBasso DC07 PRO, iBasso DX180, iFi Hip-Dac 3, KAEI TAP-1 DACs, FiiO K11 R2R, and Shanling H2 DAC/AMP. Generally, RA15 is easy to drive, but it is quite sensitive to source noise and it would be best to pair them with a source that is noisefree, like iBasso D16, iBasso PB5 or an amplifier like Singxer SA-1 V2.
Overall Signature – Sonically, RA15 is a fun IEM, with a V-Shaped tuning, having a stronger sub-bass and bass, slightly recessed lower midrange, and an uplifted upper midrange / treble. This creates a revealing, sharp rendering that brings details and clarity to the foreground with most music, but can also dampen male voices quite a bit, RA15 presenting female voices, or upper timbre male voices more forward than deep male voices. Soundstage is natural, and music happens around the room, with the lead instrument and singer playing close to you, but the background layer being projected farther off behind. The tuning works best with ACG music, J-Rock, J-Pop, EDM and commercial music in general, being a bit too sharp for rock and metal.
Bass – Starting with a deep, powerful low-end, RA15 has a sloppy and powerful touch-down at 20 Hz, with the highest amount of energy starting around 30Hz, and with the sub-bass being more present and having more energy than the upper bass, creating what is considered a high-resolution sound. This gives music a strong presence and body, while avoiding having too much bloomy and boominess. There’s a certain sense of depth to the sound, and bass has a natural-slow speed, which makes it really pleasing and satisfying to hear. With the right music, bass is earth-shattering, deep-rumbling and makes you feel like you’ve been thrown in the middle of a crowded nightclub.
Midrange – Going for a fairly sharp and thin sounding midrange, RA15 pairs well with anime-centric music, including covers of rock songs sang by Japanese artists, J-Pop and J-Rock in general, with a good emphasis on higher pitched female voices and violins, pianos and emotional music, but far less presence for deep male voices. This means that most serious and deep-pitched sounding music comes through as fairly thin or sharp, while both sad and happy music sounds emotional and vivid. There’s a certain peak around 8 kHz with another one lower around 5 kHz, both of which are visible on the graphs provided by Nf Acous, and which are also audible while listening to RA 15.
Treble – If you enjoy a sharp, well-defined sound, you will love RA15, as they really have an excellent resolution and clarity, although this extra sharpness can translate to fatigue and too much energy in the upper end with rock and metal. This being said, the tuning is satisfying to hear, reveals information and details in music which typically are glossed over by entry-level IEMS, and RA15 is quite a performer when it comes to sounding as clean as possible. The lower treble is much stronger than the upper treble.
Dynamics / PRaT / Textures – The dynamic range is natural, with the sound having a sharp tune, but a lean texture in the treble, a smooth, lean texture in the midrange. Bass has a very smooth and lean texture, this entire sound rendering square waves and textures in the most relaxing, leanest and most fatigue-free way possible.
Loudness Saturation Gradient – Volume control is good, as RA15 does not degrade its sonic quality at higher volume, but they get more aggressive at higher volumes, which makes the sound a bit hard to enjoy if you like to blast it loud. There’s a certain tendency for them to become sharper too, at loud volumes, but dynamic range stays consistent across all volumes, which allows one to enjoy a wider range of music styles.
Soundstage – Although the soundstage size is natural, and music is rendered as if playing around you in the same room, imaging and layering are top notch, with a strong instrument separation and definition. In fact, RA15 has one of the best instrument separation levels even compared to midrange IEMS from the 300 USD price range, although there are other reasons to consider a pricier IEM like a richer package, as RA15 doesn’t have much of a transport case.
Value and Conclusion
With a pocket-friendly price point of 89 USD, RA15 presents a good value, and although the package is fairly simplistic, having just the bass depth, treble extension and resolution to more than justify the asking price. Combined with a very good wearing experience and comfort, and a reliable build quality, RA15 is an excellent detail to explore right now if you’re looking for a reliable high-quality Entry-Level IEM.
At the end of the day, if you’re looking for a V-shaped or a U-Shaped sound but are low on cash, if you want to experience a deep rumble in the bass, but a refined, emotional female voice, all combined with a really good resolution and a sharp midrange, you can’t miss NF Acous RA15, one of the most interesting entry-level IEMs.
Product Link
Amazon – https://amzn.to/48bfAAL
Aliexpress – https://s.click.aliexpress.com/e/_DCoDLhx
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!
https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu
https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7
https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5
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