[size=24.57px]Acknowledgment  [/size]

Thank you Eric at Effect Audio for making the HeadFi tour of the Arthur and Excalibur pairing possible and letting me join in. I was provided the Arthur/Excalibur on loan in exchange for my honest opinion.

This review was originally published on my blog.

Introduction

I’ve had the recent privilege of getting extended listening with some truly excellent IEMs. In my listening there seems to be an almost continuous forward progression toward infinite expenditures. The Effect Audio Arthur and its bespoke Excalibur cable follow this trajectory. The Arthur and Excalibur combination is the result of research and development in partnership between two companies: Empire Ears and Effect Audio.  Jack Vang and the crew at Empire Ears designed and built the Arthur IEM in the United States with tuning and design input from Effect Audio, and Effect Audio designed and constructed Excalibur in Singapore. Some folks must have racked up some pretty sweet frequent flyer miles.

Useability: Form & Function

Packaging and accessories

The Arthur box is mirrored cardboard and very hard to photograph without showing the clutter in my home office/anywhere-else-in-my-house.

Inside is a magnetic latching case with a ribbon release. Accessories included a heavy duty case with cut foam compartments for the IEMs, the cable and the cleaning tool; two soft velvet bags (one large and one small), a polishing cloth, a cleaning tool, and a quick start guide that tells you how to maintain your new flagship headphones and how not to blow up your ears. The Arthur is very sensitive, so I would heed the listening volume advice.

Arthur

The Arthur is beautiful to look at. I really like the slight lavender hue to the transparent shell, and the red jade like finish of the faceplate is equally lovely. When combined with the Excalibur cable the setup is truly a show-stopper on looks. So much better than a knock-out punch. I believe more options are available for finish, as Empire Ears is the maker of the IEM portion and they do lots of customisation.

When it comes to fit though, I had troubles.

The demo unit only came with three sizes of Spinfits and none of them held firmly enough with the bulk of the Arthur’s shell. It isn’t heavy, but it is distributed enough to require some grippy tips to stay in. Usually when I need grippy tips, my favourites are the Spinfit CP220 biflange tips. I tried these and could get a secure fit and seal, but I had to jam them in so deep that it wasn’t terribly comfortable. I then moved on to my Comply T400 Isolates. I tend to prefer silicone tips for most IEMs as they are more neutral than foam tips. Foam tips generally soften treble and boost midbass, in my experience. There was no way to avoid using foam if I wanted comfort and secure fit and seal with the Arthur. However, my go to Isolate series, and the white foamies that came with the Unique Melody Miracle v2 have too wide bores for the nozzle on the Arthur. This is a significant oversight, in my opinion, as the Comply Isolates are some of the most popular aftermarket tips. They are the tips that are included with most IEMs that include Comply foam tips (generally 300-500 series). Luckily, I’ve got a lot of tips on hand, and my RHA gear came with Comply TSX-200 tips that have a little bit smaller bore. For this review I will use the TSX-200 throughout. Because the 400 series tends to be the standard size for high end universal IEMs, it might be a good idea for the nozzle size to be updated, or to include a few pairs of T200 Comply foam tips. Most folks will be reaching for T300 to T500 series tips for their high end universals. The sheer size of these can be seen in the image below.

For folks buying at this end of the price spectrum though, the best bet is likely going for the custom version of the Arthur. Customs will have none of the fit issues or tip rolling trials that I ran across. No need to toss Arthur in the lake.

Excalibur bespoke cable

Lucky for me, I’ve got the Effect Audio Ares II+ as my standard cable on the Noble Kaiser Encore and know the Noble Kaiser Encore combo with the Ares II+ very well. For useability, the Excalibur is markedly better. It uses the same gauge wire (24 AWG) but uses a more delicate casing that is both more flexible and lighter. When sitting atop the ear it has the feel of a smaller gauge wire. The tops of my ears are sensitive, and I get some irritation after having the Ares II+ on my ears for several hours, but I never experienced this with the Excalibur.

On looks, both the Ares II+ and the Excalibur are stunning, but the Excalibur takes it to a whole new level. The micro-coiling of the Litz wire in the delicate sheathing, the easy twirling of the cable has a visual and tactile evocativeness akin to a diamond dust encrusted silver chain. It positively shimmers, I feel like a hip-hop superstar rocking bling 20 times my paygrade. The cable is a piece of art. It isn’t just a headphone cable, it is jewelry, and a statement piece at that. The warm copper and chunkier presentation of the Ares II+ are not nearly as arresting to the senses—visual or tactile.

For sound, differences are very subtle. I listened in a volume matched comparison, but without having duplicate IEMs for switching the time between switches, due to unattaching and re-attaching cables, makes it so I can’t guarantee the veracity of my hearing. What I hear is just as likely to be bias due to the more refined looks of the Excalibur as real difference—we hear with all our senses, and our eyes can bias us.  With that huuuuuuge caveat, this is what I think I hear: the Excalibur is a bit more open, while also having slightly more immediate mids. Both have open sounds, but the Excalibur may be slightly more so. On Where is My Mind the female backing vocal soars a bit higher.  The Excalibur sounds a tiny bit more precise, while the Ares II+ is a bit smoother. Both are excellent. It took me several back and forth switches and several tracks to really feel out the differences between the cables. Tracks I used:  Pixies – Where is My Mind, Fleetwood Mac – Dreams, Eagles – Hotel California, Rebecca Pidgeon – Spanish Harlem.

Audio quality

Wooo hooo!

The highest praise I can give a headphone, is that when it plays well-recorded music, it sounds like a miniature version of being there. The best headphones sound like live music when fed the best music, not like a recording of music. The Arthurs have this kind of realistic representation. I turned these onto Chesky’s 30^th Anniversary set and just didn’t want to take them out of my ears for four hours—that’s a lot of jazz. I’m not even that into jazz. They were the most impressive headphone I listened to at Headroom, and I listened to HiFiMan’s Shangri-La—I got busy and missed my HE-1 session on accident. Doh!

The sound is light, breathy, full of air—to match a full-size planar magnetic. I compared these against the HiFiMAN HE-1000 V2 at Headroom and found that I actually preferred these. They punched even with the HE-1000 V2, which were my previous favourite current production headphone. They matched them on soundstage and had a midrange that was a bit more fulfilling for me. The meet setting noisy room caveat does apply for the HE-1000 V2 comparison. I didn’t do a Noble Kaiser Encore comparison due to limited time and so much to see—should have done it.

Comparisons

As usual, I did volume matching using an SPL meter at 78dB for universals, and 76dB for the UERR as it sounds louder due to deeper insertion depth. All comparisons were done using the Aune M1S (using firmware 1.3 with the more linear volume option), but not all comparisons were in balanced mode, so some differences may be due to differences in amplification (vs. Unique Melody Miracle v2).

Headphone	Cable	SE/   Balanced	Gain	Volume	~SPL
UERR	Stock 2.5mm	Balanced	Middle	66	76.4
Noble Kaiser Encore	Effect Audio Ares II+	Balanced	Low	59	78.2
Unique Melody Miracle V2	Stock	SE	Middle	66	78.2
Effect Audio Arthur	Excalibur	Balanced	Middle	42	78.2
Effect Audio Arthur	Ares II+	Balanced	Middle	40	78
Effect Audio Arthur	Excalibur	Balanced	Low	53	78.2

Unique Melody Miracle v2

Why – Strawberries less stage depth on the Unique Melody miracle. Sound is bigger and more forward but with less natural staging. Bass is a bit thicker on the Miracle. Mids are forward on the Unique Melody. There is a lot more depth and width in the Arthur. The forwardness of the signature makes the Miracle v2 less realistic sounding. Both have excellent technical capability, but the Arthur is noticeably superior. It should be for nearly 4x the price and more than double the drivers.

Listening to Carlos Heredia – Chachipen-Bulerias. The Arthur’s dimensionality and resolution is stunning. The acoustic guitar, percussive claps and singing are like being there. Tonally, the Miracle v2 is a pretty good match on this track. The whole sound is feels louder, which may be due to a boost in the mids on the Miracle v2 or recession in the mids on the Arthur. The soundstage height is impressive on the v2, but the Arthur wins easily on depth and width. Both are truly excellent headphones that have a very natural timbre.

On Led Zeppelin – D’yer Mak’er bass and mids are smoother and bigger on the Melody v2. As observed on previous tracks the sound is more forward with less stage depth and width at the same SPL. Drums have a bit more hollow sound on the Melody v2. The Arthur has a more distant presentation, with less relative weight, increasing the volume 3 clicks, which is probably a little over a decibel, brings the mids to the same weight as the Miracle v2. Unsurprisingly, this also makes the Arthur win even more on dynamics and stage. I think people will listen to the Arthur a little louder than other headphones, but when they do, boy does it step up. My normal listening level is about 78dB. I think I’d listen to the Arthur at 80dB to bring those mids forward a little bit.

The Arthur soundstage is huge on Amber Rubarth – Tundra. Hot damn.

On Yosi Horikawa – Bubbles (thanks to Warren P. Chi for the recommendation), the sound is much more delicate and nuanced on the Arthur. The Melody v2 is in your face with nuances not quite having the same delicate delineation. The Arthur is more refined. The Melody v2 is thicker sounding, but thick only in relative terms to the Arthur. The Melody v2 is not a thick sounding headphone.

Victor: On sound quality, the Arthur. It is more refined has a huge soundstage and a natural timbre and resolution. The Miracle V2 does firmly show what kind of value can be had for around $1000.

UERR

After listening to the Miracle v2, I switched to the UERR for Yosi Horikawa – Bubbles and the mids sound more like the Arthur. As the UERR is meant to be a reference headphone, I’ll take this to mean that the Arthur mids are more neutral. The UERR is a bit forward of the Arthur, so a little bit of recession in the mids is likely there. The stage is a bit wider and deeper on the Arthur. Height advantage is tight. Let’s check the Pixies – Where is My Mind for ye’ olde height difference.

Height advantage goes to the UERR for the female backing vocal on Where is My Mind. However, the tone is more natural and musical sounding on the Arthur. The UERR doesn’t make me think of live music, it lacks the lush sonic tones and richer pallet. Those mids are a little recessed on the Arthur, though, so I do believe I’m not the only one hitting volume a little. All the mids details like the little male vocals—the quiet where is my mind questioning in the back drop, are still there but quieter. I’d guess the vocal range of mids is one or two dB down from neutral. Over time your ears adjust a little bit, but the drop is definitely there.

On Strawberries by Why? Yoni Wolf’s vocals are silky smooth and emotive. The bass has great kick and the chimes and piano absolutely sparkle and splay on the Arthur. The instrument separation and bass character are phenomenal. There is definitely less width to the stage on the UERR. Resolution is good on both, but hand claps have a little bit of a thin sound to them with the UERR, like the decay has been truncated a bit. The sound is a bit thicker and firmer on the Arthur.

On D’yer Mak’er (Led Zeppelin) the sound stage is much more congested sounding on the UERR. There is less separation between instruments and a more immediate sound. It sounds louder than the Arthur, but the soundstage difference is still apparent. This louder character has me questioning whether my volume matching was perfect, but I’m not sure I can completely eliminate the potential measurement error.

Victor: Conclusions are similar to the Miracle V2. The sound quality edge goes to Arthur, but the UERR are an unquestionable value.

Noble Kaiser Encore

I listened to some of the same tracks, but included a couple curve balls when doing comparisons with the Kaiser Encore. I also used the Encore with the Effect Audio Ares II+ aftermarket cable instead of stock. This means that the total cost for the Kaiser Encore setup is about $2070 instead of $1850 (£1699). First I loaded up some Daft Punk.

On Too Long, there is some delicate high trill electronic effects and subtle static. The Arthur does a better job resolving these special effects. Similarly, after the 7 minute mark in the song—long indeed—there is some grooving bass. The Kaiser Encore has longer decay on the bass with more power. The Arthur is more compact in its bass notes. Sound preference on this bass expression will vary from person to person, but I imagine that more folks will prefer the Encores expression here. Arthur was airier for the whole track.

On Why – Strawberries the Noble has that same strong bass expression we heard on Too Long with longer decay and more presence than the Arthur. The Kaiser Encore also has smoother mids that are more forward. As noted in the UERR and Miracle V2 comparisons, the Arthur has some recession in the mids. However, treble-centric instruments like violins sound better on the Arthur. Violins are smoother and more enjoyable on this track with the Arthur. This track has some prickly violin, and that is still there on both, but the Arthur is a bit nicer.

Bubbles is a fantastic track. The Encore presents the sound in a more lush manner, whilst the Arthur is more precise, neither goes overboard on either side. The Encore is never woolly, and the Arthur is never surgical and sterile, both have wonderful musicality. The Arthur gets the resolution edge here, but the Encore has the edge on soul.

I mentioned earlier that I listened for 4 hours straight to jazz with the Arthur, which is something I just don’t do. Silly Samba by Clark Terry is a standout track on a standout 30^thAnniversary Compilation from Chesky. The Arthur excels technically on this track with more air and faster bass. However, the Encore sounds a bit more organic. It has lusher horns, whilst the Arthur sounds a bit drier.

The Encore’s extra weight in the mids gives extra emotional force to tracks. I find much of the emotion in tracks lies in the mids, so the Encore’s lush brushstrokes really paint a beautiful picture.

Like on other songs, Encore is more aggressive and forceful on Rage Against the Machine – Take the Power Back. Drums have more kick and push more air. The mids have fuller body and lusher dynamics. The Arthur is precise with calculated crunchy guitars and sharp focus. Because of the recession in Arthur’s mids, the mids on the Encore sound clearer.

Verdict: This is very tight. The Arthur has greater technical capabilities (bigger soundstage, better detail resolution), but it costs almost double what the Encore does. It has a bigger soundstage and better resolution. However, it lacks the emotional weight that the Encore carries and the raw power in the lows and low mids. The Arthur can rock, but not like the Encore rocks. On tracks that require complex spatial resolution and precise instrumentation, the Arthur wins, but this isn’t a huge amount of my more rock-oriented library. Signature wise, I think I narrowly prefer the Encore, but it wouldn’t be on all tracks and I miss the soundstage and perfect clarity and resolution of the Arthur already. Winner, by a hair: Noble Kaiser Encore for better value and a sound signature that fits more of my music.

Specifications

Much like with the Noble Kaiser Encore, Empire Ears and Effect Audio aren’t providing a whole lot of information. There is no frequency response curve, no data on sensitivity, and a throwaway 20hz to 20Khz frequency response range given. I tested the frequency response with tones and I can hear 10hz and 23Khz with the Arthur. It is not lacking in any way in extension on either end of the spectrum.

Specifications
Price	$3799
Drivers	14 drivers per ear (2 low, 6 mid, 6 high)
Crossover	8 way passive crossover
Frequency Response	20hz to 20Khz
Noise Isolation	28dB ± 2dB

Conclusions

The Effect Audio Arthur is a special piece of kit. I found it competed with the full-size open ear HiFiMAN HE-1000 V2, which is quite a feat. I haven’t heard a more technically competent IEM than the Arthur. It’s soundstage is spectacular with jaw-dropping width and depth. It has precise imaging and exceptional resolution. The accompanying Excalibur cable is a work of art well-executed by Effect Audio and premium in every way. The Silver-Gold Litz wire oozes luxury with glittering facade, and presence when it coils coils round the top of your ear akin to the lightness of a silken. The Arthur is a statement piece in every way. The Excalibur cable makes you feel like rich person, even if you are of more modest means.

Whether the Arthur is your ideal headphone likely depends more on the type of music you listen to. If you are into Jazz and Classical, I think the Arthur will be nearly perfect. If you listen to more rock, like myself, you may find that you want a bit more emotional investment in the mids and lusher fuller bass character like that found on the Noble Kaiser Encore. I haven’t heard better for soundstage in any IEM than what the Arthur accomplishes. It is truly astounding.

 

Empire Ears & Effect Audio Collaboration




Intro

Specifications
Arthur

1. frequency response: 20Hz to 20kHz
   
2. Sensitivity: 21ohm @ 1mw
   
3. 14 Balanced Armature drivers (6 highs, 6 mids, 2 lows) with Effect Audio’s Silver and Copper internal wiring
   
4. Crossover type: 8-way passive crossover
   
5. Noise Isolation: -28 dB +/- 2
   
6. MSRP: $3799
   

Excalibur Cable

1. 24awg UPOCC Gold/Silver Multi Bundle Litz cable
   

Testing Equipment

We have used quite a few gear to unleash its full potential.
List goes like this:

1. HM901S (Main Source)
   
2. Chord MoJo
   
3. Astell&Kern AK120
   
4. Audioquest Dragonfly Black
   

Accessories

1. Empire Ears Aegis Case
   
2. Dust Bag
   
3. IEM Pouch
   
4. Cleaning Tool
   
5. User Guide
   

Design | Build | Fit

Arthur’s housing is made of acrylic and it has a fairly comfortable body shape. The nozzle part is a bit long for me but I didn’t have any comfort issues. There is no QC flaw on the body and faceplate. I love the design of Arthur. It looks insanely premium and look gorgeous. Every person who saw the Arthur fallen in love. There is not much to say about product quality and design. Just perfect!

Sound

The first thing that caught my attention when I first listened to Arthur, was its liveliness. When you listen to the music, you feel a sense of dynamism and rhythm. Arthur does not have a sharp character, it is rather musical and it is quite detailed. To wrap it up, Arthur is smoother, more musical and more harmonious than the Zeus-R. Zeus-R is a bit more technical and detailed and it felts sterile. What I like the most about Arthur is the texture and clean midrange frequencies. While the instruments are pure and beautifully played, the vocals are in perfect clarity and emotional. Arthur’s background is also quite dark, improving the sense of imaging even further. I would like to mention that Arthur is prone to hiss but not as much as Zeus-R. Also, iPhone can easily drive Arthur, but of course, Arthur deserve much more than that.

Low Freqs

I am not a “true basshead” but for me, bass is a very important aspect of an any IEM because it provides the excitement factor. I prefer strong, prominent and tight bass.

Arthur has a strong bass but it doesn’t reach too deep, so some bass lovers might find a bit light, for me it has great amount of bass. Don’t get me wrong, it has nice amount but it is not like bass-head level. Bass is organic and natural and you do not feel the “classic dryness” of balanced armatures, but it could’ve been definitely better. Bass region attack and decay is actually well-done, it can react to a twin pedal, or high bpm EDM tracks without hassle.

As I mentioned before, Arthur is not a basshead earphone but the bass is quite satisfied level. Bass is never bleeds into the midrange and always remains controlled. Generally the bass is perfectly balanced with the rest of the sound spectrum. You do not feel that cold-boring bass of the armature drives. It has fairly high quality presentation and I can easily call an all-rounder for Arthur.

Mid Freqs

For me, the best part of the Arthur is definitely mid region.

Midbass is dense, bodied and controlled. It is also rich, smooth and lush with a nice fullness to it. And seriously detailed.

The vocals are realistic and vibrant. Especially, female vocals are amazing. Mid is relatively close but this presentation is not as like the UM Pro30. There is absolutely no mixing or losing control in fast passages. It can handle very well in fast and complicated passages. Music plays clearly and quality even in the most complicated or upsetting places. I like Arthur for stringed instruments mostly. I listened to Le Trio Joubran – Masar album with a great pleasure. Every vibration and details in the stringed instruments are gives amazing listening experience. I can easily say that, this is the best mid performance I’ve heard so far.





High Freqs
Arthur has amazingly clear, detailed as is it expected but these trebles are not in the brain piercing densities and brittleness, they are conformable and consistent, soft and natural. Very easy to focus on the sound and you can catch every single details in the music. Arthur has not a sharp treble presentation, contrary it is smooth and tamed. The treble never harsh or any hints of sibilance, even with the bad recordings.





Soundstage, Imaging and Instrument Separation - Dynamics - Speed - Articulacy

The Arthur has both horizontally and vertically wide stage. The locations of the instruments are successfully positioned and all can be picked very clearly because of the relatively forwardness of the vocals. The vertical extension may be somewhat limited but after hearing the instruments, these thoughts are starting to disappear. The details are also presented clearly.




Excalibur Cable:

I think the most beautiful cable in the market right now. The cable is as soft as I expected. It is soft like PW No5 and unbelievably comfortable and ergonomic. The Excalibur cable Is a bit warmer and it’s adding details and resolution. Who have brighter earphone, you can use Excalibur. When I use with my Zeus-R it brings more sub bass and body of the sound.






Comparison:



Arthur vs. Oriolus MK2: Oriolus has deeper and stronger bass but at the same time it is slower than the Arthur. Here is the advantage of the armature drivers. The strongest part of Oriolus is in the mid section, and I can say that Oriolus is much more emotional than Arthur and also it is more forward. While Oriolus has more dramatic and mildly presentation, Arthur has more realistic and more detailed. In the treble area Arthur has a higher resolution and extended better. As a soundstage, Arthur has a larger scene. The instruments are spread out over wider area. Oriolus is more intimate and instruments are centered in the soundstage. Overall, Arthur is better earphone and it’s special tuning make sounds beautiful.

Arthur vs S-EM9 : The S-EM9 is one of my favorite earphones. Probably it should be the fastest earphone I have ever listened to.. Compared to Arthur, the S-EM9 is little dark and the music plays from a slightly thicker note. Bass is faster and stronger than Arthur. S-EM9 is more successful earphone for EDM like genres. Soundstage , the S-EM9 has a narrower stage in the transverse direction, but I can say that both are almost equal in details. In Mid side, I can easily say that Arthur is clean winner. It is more detailed, cleaner and more accurate. The S-EM9 feels a little bit colored and unnatural. The treble frequencies are another story. The S-EM9 is one of the best trebles I’ve ever heard. It is very successful in terms of separation and resolution. Although the amount is the same of the both earphones, Arthur creates a bit more space between instruments and separation is one step ahead. Both earphones are quite musical and impressive, they are differing in their presentation.


Arthur vs. Zeus-R: Two big brothers, two different sound signatures. They are technically same but they are differing in tunes and that make them different from each other. Arthur is more smoother and the mid areas is more musical. Arthur has forward and slightly emphasis presentation in the mid range. Zeus-R is more aggressive, detailed and transparent on the treble, which makes the resolution is more prominent. Zeus-R is plays a bit colder compared to the Arthur. Zeus-R is also quite musical, but it is more detailed and transparency is a better. Arthur is fuller and stronger when I compared with Zeus-R. Soundstage of the Zeus-R is a bit wider and airier, and I believe because of slightly laid back mid range. Arthur is more vivid and smooth on treble, and Zeus-R is more aggressive and sharper. Both earphone are technically superior and amazing.



(Zeus-R & Arthur)









Summary

Arthur is a really premium product and you are feeling its amazingly nice looking housing and premium accessories. And of course one of the best IEM on the market I believe. If you like warmer, lust sound and high level of details you won’t feel any regret, go for it. But watch out! Expensive…

Effect Audio: Arthur+Excalibur

 
Introduction
            Arthur is a special collaboration between Effect Audio, a cable manufacturer in Singapore, and Empire Ears, an iem manufacturer in USA. I was lucky enough to be selected as part of the Arthur Europe and USA tour. Arthur is a free loan that will be returned to Effect Audio at the end of the 7-day review period.
Specification and Details


 
Arthur

1. Price: $3799.00
2. Drivers: 14 Balanced Armature drivers (6 highs, 6 mids, 2 lows) with Silver and Copper internal wiring
3. Crossover: 8-way crossover
4. Frequency Response: 20 Hz – 20,000 Hz
5. Impedance: 21 Ohm @ 1mw
6. Noise Isolation: -28 dB +/- 2

Excalibur

1. 24 AWG
2. 4 Wire Braid
3. UPOCC Gold+Silver 7 Bundled Core Litz

Build and Fit
            Arthur is the same size as Zeus-XIV and Zeus-R. It is quite small for a 14-driver iem. I use medium comply foam tips in this review because spinfit tip failed to give me a perfect fit and isolation.
 
Sound Impressions
Source: AK380Cu
Tips: Comply foam T-500 Medium
Music Genre: Pop, Jazz, Easy listening, Rock, EDM, Concert Record
File Resolution: 16bit 44.1KHz, 24bit 44.1 KHz, 24bit 96KHz, DSD
Presentation
Arthur is an engaging iem with full sound. The sound stage is deep and wide in comparison with typical balanced armature iems such as SE846, JH Roxanne, and its brothers Zeus-XIV and Zeus-R. You will feel the airness in the stage area of the iem. It sounds lively and packs full clarity, details and resolution of the song. Separation is the beast for Arthur. However, Arthur sometimes could not sound harmonize because of its ability to separate the instruments. Also, Arthur does not possess a good dynamic presentation of the sound. The dynamic presentation of Arthur feels like several steps of stair. It is not seamless maybe due to its speed.
Bass
Arthur’s bass is very powerful and engaging but the bass is not too close to your ear. The note is thick and has a long decay time. Deep bass is very rumble. Overall, bass is punchy and impactful with excellent details.
Mid
Vocal is neither too forward nor laid-back but you will still feel that the singer is in front of you. Also, you will feel the power from the singer. Note sound thick, clear, and engaging.
Treble
Arthur’s treble is not harsh and piercing but sharp. It is very detail, precise, and accurate. The sparkle of percussion is very beautiful. Treble is brighter than JH siren series iem.
Comparison
Arthur+Excalibur Vs Zeus-XR G1+ Mars+Leonidas 8-wire Bespoke
Soundstage: Zeus-XR G1 has a wider soundstage than Arthur. I suspect this is cause by ADEL Module. The depth of the soundstage is similar to each other.
Separation: Arthur wins be a tiny margin. But a better separation in Arthur costs it to be less harmonized comparing to Zeus-XR
Dynamic Presentation: Zeus-XR has a better dynamic presentation. The dynamic presentation in Zeus-XR feels seamless while Arthur’s dynamic presentation feels like several small steps of stair.
Bass: Arthur has a better bass comparing to its brothers Zeus-XIV and Zeus. Bass in Arthur has a longer decay time, thicker note, more rumbling, and better impacts and punches.
Mid: Arthur positions vocal better than Zeus-XR. Zeus-XIV’s vocal is a bit too forward while Zeus-R’s is too laid-back. Arthur’s vocal is placed in the right position between the Zeus-XIV and Zeus-R
High: I would call a tie for treble presentation and performance between Arthur and Zeus-XR. Arthur’s treble is sharper than Zeus’s which could bring fatigue after a long listening time.
 
Conclusion
Arthur is one of a kind TOTL iem like its brothers Zeus-XR. I would not say which one is better because it is unfair to judge them since all of them have a different sound signature. If you seek a reference iem, go for Zeus-R. If you like mid centric sound with harmonic and seamless dynamic presentation, go for Zeus-XIV. If you seek a great rumble, punchy bass, detail mid and high, and lively engaging sound, go for Arthur.
End Note
Thank you Effect Audio for giving me this chance to demo Arthur+Excalibur. It is a masterpiece TOTL iem. Empire Ears, you did a great job in tuning Arthur. Finally, I am hoping that Empire Ears will come up with an iem that combine the bass and mid from Arthur, high from Zeus-XR, details and clarity from Arthur, dynamic presentation and harmonize from Zeus-XR together. That would be my dream iem.
 
Price: 3/5
Soundstage: 5/5
Bass: 5/5
Mid: 5/5
Treble: 5/5
Value: 4/5