Review: Empire Ears ESR – Studio Energizer

Empire Ears ESR
Empire Ears ESR

Injecting the knowledge obtained from the studio into the development of the Empire Studio Reference (ESR), Empire Ears tuned this in-ear monitor (IEM) uniquely for discerning producers and engineers who need a neutral, uncolored reference IEM.

I bought this pair of IEMs at full retail price. This is not a sponsored post, but an honest review written from a consumer’s point of view. Dollar to performance ratio is included below.


Gathering a team of passionate engineers, musicians, and audiophiles, Empire Ears desires to design the finest IEMs in the world. With over 30 years of experience in this industry, Empire Ears successfully realized its ambitions with the release of the award-winning Zeus in 2015. The Legend X soon took over Zeus’s legacy and it continues to prove Empire Ears’s quality in the industry.

As the leader in our industry, we are committed to never give up in our search for the extraordinary. Immersive sound signatures, cutting-edge design, and unrivaled build quality are the hallmarks of our IEM systems. – Empire Ears

Leveraging the experience gained in building the well-received Spartan, ESR is designed to present a more refined neutrality across the frequency spectrum. Adding pleasant warmth and greater body to the sound, it yields a more exciting midrange and ultimately generates greater resolution.

With this implementation, the ESR stands out for its well-balanced sound. It is one of the most balanced IEMs in Empire Ears’s lineup. The ESR’s price to performance ratio creates a serious challenge to other IEM manufacturers. We will further discuss this in this review.

Empire Ears ESR

Empire Ears ESR

“The Empire Ears ESR is a great choice not only those who are working in a studio; it also fits well for those who value neutrality in their IEMs.”

What We Like
  • Neutral tonality
  • Excellent stock cable
  • Decent accessories
  • Freedom to customize (termination and universal vs custom)
What We Don't Like
  • Shell may be too large for some
  • Nozzle is short and there’s no lip to secure the ear tips


I really like the packaging of Empire Ears: grand, elegant, while minimalistic. When you purchase any IEM from Empire Ears, the first thing that will catch your attention is the huge logo on the black box.

A silver Empire Ears Logo will catch your attention immediately
A silver Empire Ears Logo will catch your attention immediately

Opening the black box, you will find these accessories included:

  • Aegis Case
  • Carrying pouch for Aegis Case
  • Carrying pouch for ESR
  • Cleaning cloth
  • Final Audio Type E ear tips (XS, S, M, L, XL)
  • Cleaning tool
Cleaning cloth, quick start guide, and two pouches in the box.
The Aegis Case.
The Aegis Case.

Opening the Aegis case, you find the ESR lying comfortably with the Effect Audio Ares II cable pre-installed. Besides the IEM, the additional ear tips and cleaning tool are also stored in the case.

Final Audio Type E ear tips and cleaning tool.
Final Audio Type E ear tips and cleaning tool.
ESR with pre-installed Effect Audio Ares II cable


  • 3 proprietary Empire Balanced Armature Drivers
  • 1 low, 1 mid, 1 high
  • 4-way synX crossover network
  • Resonance Mitigation Technology (A.R.C)
  • Impedance: 19.3 ohms @ 1kHz
  • Frequency response: 10 Hz – 40kHz
  • Sensitivity: 112dB @ 1kHz, 1mW
  • UPOCC 26AWG handcrafted cable by Effect Audio

Build, Fit and Isolation

Empire Ears utilizes acrylic shell for most of its universal line-up. ESR has the same acrylic shell. The logo on the shell varies according to the models. The shell is relatively big when compared to other models such as the Jomo Audio Haka and Symphonium Audio Aurora that I recently reviewed.

However, the relatively large IEMs sit well in my ear with the correct choice of ear tips. I am using the Final Audio Type E ear tips provided in the box. I like these ear tips for their good isolation.

Gold Empire Ears logo on black acrylic shell
Gold Empire Ears logo on black acrylic shell

There are 3 bores on the nozzle. The nozzle is relatively big and slightly shorter compared to other IEMs on the market. This might cause some issues in finding a good ear tip for the universal model for some users. I am lucky because the Type E ear tips fit me well.

3 bores found on the nozzle of ESR

Empire Ears ESR utilizes a 0.78mm non-recessed 2 pin connector. This is a common market standard, so a lot of third party cables can be found to replace or upgrade the original cable.

0.78mm non-recessed 2-pin connector found on top of the shell

The cable provided in the box is the Effect Audio Ares II: a 26AWG Ultra Purity Ohno Continuous Cast (UPOCC) copper cable. This is an excellent cable with rigid braiding and a strong right-angled 3.5mm jack. When ordering this IEM, I was given the freedom to choose the termination: 2.5mm, 3.5mm, or 4.4mm. I chose 3.5mm so I can pair it with most of my amplifiers and digital audio players (DAPs).

Effect Audio Ares II
Effect Audio Ares II
A rigid right-angled 3.5mm jack
A rigid right-angled 3.5mm jack
2 pin connector with heat-shrinked ear guides
2 pin connector with heat-shrinked ear guides
Black Y-split with Effect Audio and Empire Ears logo
Black Y-split with Effect Audio and Empire Ears logo


For this review, I paired ESR with the Sony NW-WM1A, one of my favorite DAPs, and I used the unbalanced cable. For ear tips, I used the Final Audio Type E ear tips which are included in the package.

Empire Ears ESR with Sony NW-WM1A
Empire Ears ESR with Sony NW-WM1A


Based on the ESR’s name itself, I suspected the presentation would be rather flat and dull before even listening to this IEM. Most of the studio reference IEMs exhibit this kind of sound signature in my experience. Wrong! So very wrong. I “wowed” instantly when I first listened to this IEM. It is lively and full of emotions.

The overall sound signature can be considered neutral. I read some reviews while I listened to this IEM and noted that some reviewers do not consider it to be a neutral IEM. Here I wish to clarify what neutral means to me. Normally I call an IEM neutral when there is no emphasis or deficit at any region in the frequency spectrum. I think ESR did very well here. I call this a neutral IEM.

The response is very fast and accurate. This speed and accuracy is essential for musicians, artists, and engineers when producing music. The soundstage is wide and deep. I cannot find an IEM that has a better soundstage than Empire Ears’s IEMs. This is one of the unique selling points of Empire Ears.

Details are well-separated and the layering of instruments is presented decently. I do not find any congestion when listening to any of the review tracks. I can submerge myself in the sea of musicality when listening to ESR. It is an enjoyable reference IEM.

Another close look at Empire Ears ESR
Another close look at Empire Ears ESR


Deep, very deep. The depth of the soundstage is created mostly by the deep extension of the bass. The bass response is very fast and I appreciate fast bass (short decay duration). Slow bass (bass that decays slowly) can give a track more emotion and may be more gentle on your eardrums, but slow bass bleeding into the mids is a big taboo.

The body is full and well controlled. The amount of bass does not affect the rest of the frequency spectrum. This IEM is precisely and accurately tuned by Empire Ears!

The sub-bass rumble is when the ESR begins to shine. I am not a bass head but I really appreciate good quality lows. I fell in love with the sub-bass when I first listened to this IEM.

The lows response is very different when compared to the X series from Empire Ears.

If you are a fan of the X series (Bravado, Legend X, etc), you might need to audition this before making an impulsive purchase.

X series has a softer approach in the bass regions, like a wave hitting the beach, while the ESR’s bass is like a punch hitting a sandbag. This kind of solid impact is the best description of the ESR’s bass. Nonetheless, it is very accurate and the presence is significant!

Empire Ears ESR
Empire Ears ESR


If you read my previous reviews, you will understand how much I appreciate good mids. I am a Mandopop and Cantopop lover. Good vocals are essential for me. What does“good mids” mean to me? The texture needs to be thick enough. What do I mean?

Texture is how the vocals and other mid frequency instruments are combined in a composition, thus determining the overall presentation of the mids in a piece.

This is very tricky because the vocals become too honky when the texture is too thick. When the vocals are too thin, they lose the spotlight. The stage will be taken over by other frequency regions.

The ESR has a good grasp on texture. The mids are rich, thick, and juicy. It has sufficient air and space in the mids to make the vocalists sound lively. When I am listening to Teresa Teng, she sounds sweet and silky smooth.

I always use Teng’s tracks as a reference when writing my impressions on mids for an IEM. Her vocals are special: you need a good amount of air to make them lively and the body needs to be sufficiently thick at the same time.

It is tricky, but I am glad that ESR got it right!

Positioning is tricky for the mids as well. Normally I prefer the vocalists to be positioned in the center of the stage, taking the spotlight, but sometimes it can become extreme. Overly forward vocals are a no-no for me because they become shouty, like the vocalist shouting at you without any musical instruments playing.

As mentioned earlier, the ESR is a relatively neutral IEM. There is no bias in any region of the frequency spectrum. The mids are positioned well in the middle and I appreciate this presentation. I get what I like in this IEM in both the lows and the mids.

Empire Ears ESR
Empire Ears ESR


The highs are one of the key factors determining how long you can listen. If the IEM has peaks in the highs or is too energetic, it will cause fatigue during long listening sessions. ESR does not belong in the listening fatigue category.

Personally, I have a good tolerance for highs. I seldom find an IEM to be too bright. I like the highs on the ESR. They are airy and spacious. If lows are a punch landing on a sandbag, the highs are a gentle breeze bringing you comfort.

When the punchy lows meet with the meaty mids and breezy highs – simply amazing.

The extension and decay on the highs is well-controlled. A lot of IEM manufacturers neglect the treble, causing the highs to extend and decay badly. What does poor treble extension or decay sound like? It sounds exactly like distortion. The silky highs break and form unbearable distortion at high frequency. It can be piercing sometimes, ruining the overall experience.

All these mentioned issues were addressed in designing the ESR. I salute the professionalism and mindfulness of the team who crafted the ESR.

Another look at the ESR-WM1A pairing
Another look at the ESR-WM1A pairing


The Empire Ears ESR is a great choice not only those who are working in a studio; it also fits well for those who value neutrality in their IEMs. The number of accessories, especially the Ares II from Effect Audio, made the ESR package more attractive. The ESR is fully built by the Empire Ears team in the USA to maintain the high quality.

The universal ESR retails for USD899. It can be purchased at most of the major audio retailers such as ConnectIT by Jade Gift Shop (Singapore) or directly from Empire Ears. For those who wish to get a custom version, the price starts at USD999 and the final price will depend on the customization of the artwork.

Empire Ears managed to challenge the common stereotype of studio reference IEMs. They are no longer dull and lifeless. The ESR is proof to the community that studio reference IEMs can sound fun and engaging!

Well done, Empire Ears!

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