JM Audio NRG Prototype
I want to start by saying that I know it has been a long time since I last updated the site. To be transparent, I’ve been writing for so long that it sometimes feels like work, especially since I have a full-time career. I now write when I feel inspired or truly want to create. Today, I feel both inspired and eager to write again.
In 2022, I introduced everyone to John Massaria when I first tried his Kennerton Redux of the Kennerton Gjallahorn GH50 JM Edition.
At this point, I refer to John as the Mad Scientist for his modifications, but now he has transformed into more of an Alchemist, creating something extraordinary. I currently own two of John’s offerings: the XTC ².5 Euphoric Xtreme Trip Limited Edition in Brazilian Tiger Burl Wood, and the prototype NRG. Both the XTC (Ecstasy) and the NRG (Energy) are incredible products. I started reviewing the 2.5 XTC a while back and then got sidetracked. Without a doubt I promise I will finish that review and provide a comparison between the two.
I am kind of putting the cart before the horse, since I have only had the NRG for two days and I have had the 2.5’s since March of 2024. The 2.5’s have been back in John’s lab a couple times for retuning and a new headband, so when I do the review that is what you will see. Scroll through the first page of JM Audio and you will see discussions of tuning etc. The NRG headphones are custom designed and tuned for Bliss or Heavy Bliss, so I can only speak of my tuning and design.
I need to throw up this huge disclaimer; I would not consider my NRG to be fully seasoned, while they haven’t hardly left my head in two days, my sound comments may differ when I do my comparison vs. the 2.5 XTC further down the road.
A Little Technical Stuff:
Unboxing and Accessories:
Includes premium lockable vault-style case with headphones, chosen cable, two earpad sets, tuning card, lapel pin, keys, and Allen wrench for headband adjustment. Contents vary by specification.
Build Quality and Fit:
The NRG headphones offer exceptional comfort. Weighing 427 grams, their design ensures even weight distribution and a perfect over-ear fit. Extended listening sessions (hours) were possible without discomfort. Build quality is commendable. Future customization options, potentially including a selection of ear cup materials, are anticipated but remain unconfirmed.
Listening Setup:
The listening trail utilizes a Shanling M8T digital audio player as the source. The player has three operational modes: Transistor, Triode Tube, and Ultra-Linear Tube. My initial preference is for the Transistor and Triode Tube modes. I utilized a 4.4mm Arctic Cables Hybrid (silver & copper) cable. High-resolution audio files served as the test material, comprising 24-bit FLAC files and Tidal Masters (24-bit/48kHz FLAC).
Moving on to the sound section….
Individual listener experiences are subjective, and results may vary. This field is inherently subjective, and my evaluations, like those of any other reviewer, represent a personal perspective. My expertise is limited to expressing my informed opinions.
My assessment of the sound signature is as follows: Sub-bass reproduction is characterized by undistorted rumble. The bass response is described as snappy, avoiding bloat and maintaining frequency separation. It exhibits a fast, high-energy character. The midrange is detailed and clean, with a forward presentation that, while prominent, avoids harshness. Treble extension is excellent, rendering cymbal sounds naturally.
While this description lacks exhaustive detail, it should, in conjunction with the track-specific analyses provided below, offer a comprehensive understanding of the sonic profile. While smoother, more refined headphone options exist, the NRG possesses a distinct character. Its sound signature is analogous to a high-performance sports car, as opposed to a luxury sedan. At its current prototype price point, I can confidently state that I have not encountered a comparable product within its class.
The NRG headphones’ most striking attribute is their exceptional staging and spaciousness. The closed-back design, surprisingly, delivers a remarkably cavernous soundscape, creating an immersive and awe-inspiring listening experience.
Below are some of my notes while I was listening to the tracks below;
**Queen – Bohemian Rhapsody**: The sound is well-balanced, with a lot happening simultaneously in the song, yet it remains clear with plenty of separation between the instruments. The staging is both broad and deep, and the bass is punchy, not muddy.
**Led Zeppelin – Stairway to Heaven**: Page’s guitar intro is exceptionally clean; I can feel the plucking and slight squeaks of the strings. Plant’s vocals are front and center, while Page’s guitar remains distinct in my left ear. The overall sound is spacious, and Bonham’s drums are crisp and solid, though slightly pushed to the rear in the mix. The staging is accurate and precise.
**Eagles – Hotel California**: This track might not be the best for the NRG system. The bass line was very apparent and a bit overpowering, possibly due to the DSF file. However, when I tried the Tidal version of the song, it sounded much better. The midrange is beautifully detailed and balanced. When the drums kick in, I could feel the rumble, and Don Henley’s drumming was incredible.
**Guns N’ Roses – Sweet Child O’ Mine**: The sound is solid and well-balanced. Slash’s guitar has a smooth tonality with a bit of bite, but it’s not overly offensive.
**Michael Jackson – Billie Jean**: The bass blends naturally with the kick drum, providing perfect support for Michael’s vocals; neither the bass nor the kick drum overshadows the vocals, and in turn, the vocals do not overpower the bass.
**Marcus Miller – Detroit**: This song features impactful shifts and, of course, Marcus Miller’s signature plucky and slappy bass. The energy in the impactful sections is palpable but not harsh, and the bass slaps are crisp and well-defined, without being flabby.
**Fleetwood Mac – The Chain**: Absolutely mind-blowing. I felt like Fleetwood Mac surrounded me, and I got goosebumps when the bass kicked in. This song is a mic drop—there’s nothing more to say.
**Dave Koz – Put the Top Down**: This track showcases a wide range of frequencies. The mids are very energetic and forward, while the bass remains present, and the transitions are snappy.
**Hans Zimmer – “Why So Serious?” (The Dark Knight)**: This track heavily emphasizes sub-bass. The sub-bass adds impact without overwhelming the other frequencies. Despite John Massaria’s warnings (as it’s a prototype), I had to turn it up to test for distortion. The NRG handled it exceptionally well.
In Closing:
My initial assessment of the prototype headphones is overwhelmingly positive. While further burn-in time is required for a complete evaluation, the current performance is highly promising. Even if the sonic signature evolves with further use, the results thus far are exceptional. Given that this is a prototype, and considering John’s dedication to refinement, the final product may differ.
The comfort level is outstanding, the build quality is good, and the unboxing experience was excellent. The current tuning (Bliss Tuning +, Tight Accurate Bass with Warm Yet Extreme Detail) aligns perfectly with my preferences. It’s noteworthy that JM Audio offers customizable tuning options across their product line, including the NRG model, which the two options for NRG are Bliss or Heavy Bliss.
More to come…this wasn’t intended to be a complete review, but it does kind of appear as such. I owed the readers something after my long hiatus.
