Fir Audio Neon 4 Review

Fir Audio Neon 4 Review

Fir Audio is an exciting brand that we’re excited to delve deep into on MajorHifi. This is a high-end IEM manufacturer that deals in both universal and custom models. The Neon 4 is the lowest-priced model in their Frontier series at $2,299. Funnily enough, their lowest-priced IEM is still in the upper tier of the market. Is it worth going for, or should you save for the top dogs?

Fir Audio Neon 4 items

What You Get

  • Neon 4 IEMs
  • 2-pin 4.4mm cable
  • Genuine Leather Protective Case
  • 3 sets of ATOM XS interchangeable modules
  • Cleaning tool
  • 5 sets of ear tips
    • 3 foam
    • 2 extra silicone
  • Warranty card

Fir Audio Neon 4 single

Look & Feel

So far from what I’ve seen from Fir Audio, their builds are outstanding. The level of construction seen on the Neon 4 is super refined, combining a machined aluminum shell with a stylish sapphire glass faceplate. Its silver casing exudes a high-caliber design, while the faceplate gives it a striking aesthetic flourish. The fit can vary though, as I never got the housing to sit naturally. I would still consider the Neon 4 comfortable enough, but I never found them very isolating.

Fir Audio Neon 4 cable


The Neon 4 houses one 10mm Kinetic Bass dynamic driver, and 3 OpenDriver balanced armatures. It uses its ATOM venting system, which relieves pressure from the ear canal greatly reducing fatigue.

Fir Audio Neon 4 pair


It’s apparent what the Neon 4 is going for right from the get-go when hearing the way its soundstage operates. There’s a ton of length to the stereo field, as the width expands in a realistic manner. Surprisingly, it’s quite a linear response, with all the sound elements sitting on a flat plain. That doesn’t mean none of the performances have depth though. The Neon 4 is just extremely pinpoint accurate, and the positioning it conveys is very strict. Instruments stack in a clearly organized way, all while offering air and separation between each section. You won’t get much tallness in the instruments, but the spatial imaging still has plenty of dimension to it. It shows a fair amount of open headspace but doesn’t expand too far. Distance isn’t really felt, but the layering makes up for it. I would consider this soundstage semi-holographic, but it never completely feels like a dome. Rather this is a traditional stereo pattern with more individualized elements that bring more depth to the sonic environment.

Low End

So far from what I’ve heard from Fir Audio, the bass is always superb. The Neon 4 reflects this with a wonderfully smooth response. There isn’t any significant power or slam behind these frequencies, but the tone has an elegant impact, with a buttery surface that feels dynamic and engaging. It doesn’t call too much attention to itself, but you can constantly sense its presence. This is especially true in the sub-bass, where the Neon 4 displays some steady rumble that establishes great depth. It’s not always the most theatrical response, but the timbre is always rich with detail.


The midrange helps give each performance a fine shape, and a sense of identity in the mix. Their response is very natural, and the frequencies are well-regulated for the clearest definition possible. Everything comes through with great transparency, and each performance is given enough room to breathe. This helps with the identity of each performance, as each instrument and vocal comes together with resolving clarity. There is about an even level of drive to the mids as there are the lows, so the balance between both ranges is well-maintained.


These highs have a lot of bite. Their timbre is bright but non-fatiguing. It’s a dynamic response that offers a ton of detail in a realistic manner. It won’t shy away from some more energetic treble tones, but it always feels totally natural and not harsh. You won’t get much sparkle here, but there’s still some colorful texture to absorb. Mostly, it’s a sizzling air that possesses a cutting edge. Every instrument has a clear tail that dissipates through the sound signature beautifully.


Fir Audio has gotten pretty high on my list of brands to look out for, and the Neon 4 is another reason why. It’s a pricy name, but if the Neon 4 is any example, then they might just deserve the prestige. Sound-wise the Neon 4 is fantastic, balancing smooth lows, natural mids, and textured highs for a stellar performance.

The Fir Audio Neon 4 is available at Audio46.

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Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.