Audio Custom In-Ear Monitors IEMs Reviews

Perfect Seal AR6: Ambiance and Reference Defined

Note: Perfect Seal graciously provided the AR6 in this review.

Perfect Seal LabPS logooratories, based in Wichita Kansas, is a relatively new company in the increasingly popular custom in-ear market. The company is run by Mike Martinez, and while Perfect Seal might be new to the Head-Fi community, Mike is certainly not new to the industry. He previously worked for an early industry lab that made monitors for Sensaphonics and Fireside, in which everything was dynamic driver based at that time.

Before getting into the model being reviewed here, I wanted to share a Q&A I recently had with Mike, so he can shed a light on the Perfect Seal team and how he approaches the tunings that make up the Perfect Seal line-up:

Who are the team behind Perfect Seal Laboratories? 

Mike: Currently we are a team of four. Myself, Dave, Brad and Brandi. Though I may use the term lightly, we all are musicians except Brandi. We have a really good thing going, every one is very reliable and that makes all the difference in the world. 

How do you approach tuning a new design? Do you have target measurements or a specific sound signature in mind when you start designing an in-ear?

Mike: There are several ways and considerations into the approach of a new design. I like to start with a Diffuse Field curve then tweak things to my liking or toward whatever I feel the intended target may be wanting to hear. 

Do you use specific songs or kinds of music to gauge the tuning direction when you are designing an in-ear? If so would you mind sharing a couple?

Mike: I do have specific songs I’ll use in the design and tuning of our units. I really don’t stick with one genre but will try several. A few bands I’ll use are Candlebox, Little Wayne, Charlie Daniels, Casey Donahew, and so on. There are certain artifacts that I’ll look for. I also like to use stuff I wrote and recorded because I obviously know the intended sound intimately. 

What background do you bring to the industry that gives you a unique or different edge and/or sound?

Mike: Along with my music background, I bring my knowledge of various materials and modeling techniques. I have production methods that not too many are familiar with or even heard of. Some of which are in place and some just waiting to be incorporated. 

Do you feel your line-up has a house sound or did you set out to have completely different sound in different models?

Mike: I hear a lot about “house sounds” but I don’t feel we have a house sound. I look to offer a wide range models that way anyone could fine something they prefer. 

You offer some of your in-ears in silicone and acrylic. Are there any sound differences between the same model but built in each material? If so, to what would you attribute it?

Mike: There may be slight variations in sound between the same model being made in different materials. There could be a few reasons to explain this but my take is: 1. The material around the sound tube, insulating it. In a silicone unit, the entire run of the sound tube is in contact with the silicone. In an acrylic mold, the tube is usually in free air with canal portion of the tube encased in acrylic. 2. My second explanation is more of  a theory that involves sound waves hitting the tip of the mold. A soft mold could possibly be dampening sound waves bouncing off of the eardrum while the hard mold may not be dampening them as much, causing piggyback signals or a slight difference in sound perception. 

How would you describe your perfect sound signature?

Mike: My perfect sound signature is still evolving. The best way I could describe it is what some might describe as “V” shaped, but I wouldn’t call it that. I like sparkle in the highs (not fatiguing), clarity throughout the mid range and an elevated sub/low bass, not overly elevated, just enough to where it feels right in the mix. The AR6 has changed what I thought my ideal sound sig was, just wait until I merge the two 😉

What are the biggest differences in your professional musician customers and audiophile customers?

Mike: There are musicians who just need a tool to hear a click or the band, so that’s pretty basic. Then you have musicians with more of an audiophile sense and they may want a higher fidelity sound. The biggest difference between the professional musicians and audiophiles that I noticed, believe it or not, has nothing to do with sound. It’s actually in how the CIEM looks. Audiophiles want wild colors, cool designs, and individuality built into their CIEM’s. 

What is the most difficult part of your job/career?

Mike: That’s a tough one to answer, so maybe answering this question is, lol. Really though, it would be, being a salesman. I am not a salesman, I won’t try to convince anyone to buy our products, I simply answer any questions anyone would have about our products as honestly as I can, without adding all the extra polish to my words. I dislike being sold to, so I have no desire to push my products onto anyone else. I let people decide on their own, but I do understand in doing so, they sometimes get “sold” on another competitors products instead. 

Who or what is your favorite band?

Mike: You saved the two hardest questions (for me) for last. I’m not sure that I have a favorite food, color, or band. I like so much that it’s really hard for me to choose. Lately I have been listening to a lot more alternative, Mumford and Sons, Muse, etc….

Fast forward to today, we have Mike crafting in-ears in both acrylic and silicone, with not only balanced armature designs with up to 8 drivers per side but also hybrid designs with both dynamic and balanced armature drivers. Perfect Seal also offers canal only shells, full custom shells and hard acrylic shells with soft canals. When it comes to options, no stone is left unturned.

Recently Mike has released a new series of custom in-ears: The Ambiance Series. The first release in this series is the new Perfect Seal Flagship, the AR6. The A and R stand for Ambiance Reference and the 6 is the balanced armature driver count. The AR6 was designed with soundstage and linear frequency response goals in mind, to wit, the marketing blurb on the website states, “experience superb clarity, awesome resolution and imaging”. The AR6 is offered in acrylic and silicone but Perfect Seal will need to see your impressions first before giving the thumbs up for a silicone build, as the canal pieces in silicone will need to be a little larger than in acrylic. This is due to the 4 sound bore design and the need for more space in silicone with that many bores. Pricing starts at $950 for acrylic and goes up from there.

ARG b2b pinballBlue Purple and Green Purple Swirl on Gottlieb’s Cleopatra

Manufacturer Specs:

$950 Acrylic

  • Six Balanced Armature Drivers
  • 1 Low Driver
  • 2 Low/Mid
  • 2 Mid
  • 1 Tweeter
  • 5 way passive crossover
  • 4 sound bores
  • Standard 2 pin connector

I chose silicone for my set, as I’ve previously only had one other experience with silicone in-ears. Mike offers many possibilities when it comes to colors, designs and finishes; many of which aren’t really shown on the website, so it’s a good idea to contact Perfect Seal when ordering and discuss your aesthetic aspirations. I decided to go with a swirl of his ‘blue purple’ color along with the ‘green purple’ color. The dedicated AR6 thread on Head-Fi has some pictures of a beautiful orange acrylic set that is a must see!

Perfect Seal customs come with a customized S3 case, which is similar to an Otterbox. The customized foam insert has a slot for the cleaning tool, an open area to lay our wound cable and possibly a silica drying pod, as well as two small areas for each ear piece. The stock cable looks to be standard issue PlasticsOne Motion series cables, which comes with a 3.5mm right angle plug that is smart phone case friendly, SPC tinsel wire, rugged Y-split, neck slider and memory wire at the overmolded 2-pin connectors.

AR6 wooden table


I’d say the AR6 is a very slightly mid-centric take on reference tuning. There is a little boost in the upper mid, making it really clear sounding but not necessarily forward sounding. Bass linearity is excellent and extends into the deepest depths. Lower treble is slightly laid back from reference tuning, but picks back up in middle treble providing a nice presence and shimmer, while staying easy to listen to.

The AR6 has quickly become my favorite in-ear to grab lately. The spaciousness is frankly one of the best I’ve heard. I can’t quite put my finger on exactly how Mike is doing this. Usually designers give a little dip in the midrange and/or elevate treble to give a sense of depth and forward projection. However there is nothing recessed or dipped about the midrange here, and treble is easy on the ears; yet somehow when I put the AR6 in after something else, I hear the midrange as obviously more forward, yet the presentation is slightly in front of me, instead of being right across my eyes or in my head. And while the AR6 doesn’t sound ‘grand’ in width, like say a Tralucent 1+2, it has much more realistic feeling to size proportions and space between the instruments. The depth and precision of the image is second to none. Staging is like being in the recording room with the band but with life-sized spaciousness. There’s almost a binaural dimensionality to it. Almost. It’s really quite unlike any in-ear experience I’ve had to date.

AR6 mojo pinballAR6 with Limited Edition AK100 MK2 and Chord Mojo

Select Comparisons

AR6 vs Perfect Seal PS6 ($650)

In terms of quantity, the PS6 has greater quantity but the greater quantity is not by a large margin. Mostly its an increase in mid bass for greater impact, although there is slightly more sub bass presence as well. The AR6 bass is very linear and even across the frequency response, whereas the PS6 has a rise in mid bass, small but tasteful. This gives the PS6 a slightly fuller and richer note over the AR6. With hip hop and rap, the increase in bass is appreciated. The AR6 bass, while not as impactful, has better texture and air for improved resolution and ambiance over the PS6. Both exhibit good balance between speed and decay.

The midrange is where there is the biggest difference in presentation between the two. With the PS6, vocals sit squarely in the pocket, neither forward or recessed sounding with realistic weight and tone. In contrast the AR6 brings vocals more forward, particularly in the upper midrange. The result is that the AR6 is more resolving of low level vocal detail, like intakes of breath and throat inflections. However the fuller lower midrange and upper bass of the PS6 make for heftier male vocals with a more emotive connection. Where the PS6 may have the edge with male vocals, the AR6 is more evocative with female vocals.

The lighter note weight of the AR6 and the bump in the upper midrange brings a sense of greater clarity. Distortion guitars are airier and can really soar in the rise of tempo in a rock anthem, whereas the slightly thicker note of the PS6 is more grounded with greater dynamic impact for a richer, more musical approach.

Neither the AR6 or the PS6 are what I’d call bright or forward in treble, rather I’d label both as slightly laid back in treble. However where the AR6 is only a hair laid back in treble, the PS6 is more laid back and easy going in direct comparison. The PS6 is built for long session listening without fatigue. Even though it’s fairly laid back in treble, it still has good tonality and articulation. In contrast the AR6 has more overall treble presence and sparkle.  It is also more resolving and articulate, as well as more extended. Treble details are more apparent and easier to pick out with the AR6.

Staging, Imaging & Separation
The AR6, with it’s design attention to ambiance and space, sounds larger and more realistic in staging properties. Instrument separation and placement is one of the most articulated in an in-ear and this is where it really separates itself from it’s PS6 peer. The AR6 is much less in-head and even though the midrange is more forward, it somehow projects itself out front more-so than the PS6. The PS6 by no means sounds small but it’s just not in the same league as the AR6 when it comes to these staging properties.


AR6 vs Ultimate Ears Reference Monitor (discontinued; replaced by UERR $999)

The UERM is the most neutral in-ear I’ve had the pleasure of listening to but if there is one thing I could change on it, it would be to make the bass presence under 50 hz more present and extended. This is one area the AR6 has the upper hand; it’s is very flat and even into the lowest reaches of its bass capability which is about 25 hz before it starts rolling off heavily. Due to these differences in bass tuning, the AR6 has more deep bass rumble and low bass texture but seems just a hair lacking in mid bass impact next to the UERM. While the UERM lacks the deepest extension and rumble/texture next to the AR6, it makes up for it with more realistic drum timbre and impact. Bass details seem just a bit more solid and delineated in the UERM under direct comparison.

The UERM is known to be a hair laid back in the upper midrange, so the AR6 is a good contrast to the UERM with it’s bump in presence in that area of midrange. Similar to the PS6 comparison, the AR6 seems to be more evocative with female vocals and the UERM with male vocals but the edge the AR6 held over the PS6 is greatly reduced here.

Both the AR6 and UERM can absolutely soar with distortion guitars and rock anthems but the approach is slightly different. The AR6 does it with its rise in the upper midrange and the UERM with it’s fuller middle mid and brighter lower treble. The end result is distortion guitars have more bite, edge and crunch with AR6 but sound fuller and airier with the UERM.

Where the AR6 achieves it’s clarity and any perceived brightness is in the upper midrange, the UERM achieves it through a brighter overall presentation throughout the treble. The UERM has more lower, middle and upper treble presence. It is a clean, bright and sparkly treble that never sounds piercing or harsh to my ears. I find the AR6 treble just as resolving but it doesn’t bring treble detail to your attention as much as the UERM does. This difference in treble presence is one of the characteristics that differentiates their staging properties as well.

Staging, Imaging & Separation
Both the AR6 and UERM are two of the largest sounding in-ears in my experience but the way it’s achieved is very different. Where the UERM sounds open ended, airy and very wide, more like an outdoor venue presentation, the AR6 sounds more like an in the studio presentation. While terms like in the studio and outdoor venue read like differences between small and large, that’s not the case here at all. The AR6 staging has very realistic proportions with life size spaciousness. At times the AR6 almost presents staging details as if you are listening to binaural recordings. Everything is so precisely placed, there is a great sense of three-dimensionality to the AR6 just not achieved in anything I’ve heard before. The UERM is it’s staging compliment with the more wide and open concert appeal. While I’ve always thought the UERM displays excellent depth, and it truly does, it’s not comparable to the lifelike spaciousness of the AR6.


AR6 vs Empire Ears Zeus ($2099)

While bass on Zeus does hits a bit harder and has more rumble as well, the most obvious difference is in the reverberation of the Zeus bass. Zeus bass lingers longer, sounding bolder and richer in tone. In direct comparison the AR6 bass is tighter and faster and as a consequence the AR6 sounds a good bit leaner overall compared to Zeus. The AR6 has excellent bass texture but bass texture and reverberation are a showcase piece to the Zeus signature.

The midrange is really the star of the show on both models. Zeus has a fuller lower and middle midrange emphasis compared to the AR6, which seems more linear overall but has slight boost in the upper midrange. As a result, distortion guitars have a greater weight and heft in Zeus, again sounding thicker and richer. Next to the Zeus, the AR6 sounds leaner, airier and more nimble. Soaring guitars and dual leads truly soar with the AR6 but drop D tuning sounds heavier and sleazier with Zeus. On acoustic guitars, the AR6 brings out the sound of the pick hitting strings and the twang of the strings across the neck but Zeus brings more focus to the vibration of the strings over the sound hole and resulting reverberations.

Vocals are also treated pretty differently on both as well. With Halestorm, Lzzy’s voice really grabs you by the throat with great clarity and superb energy on the AR6; every breathe, throat inflection is revealed but on Zeus she is darker, more brooding with the greater lower midrange emphasis. In contrast, Zeus really makes the emotional connection in male vocals. Radney Fosters ‘Godspeed’ is exquisitely intimate and fraught with the love of a parent for child separated by the distance of a touring musician.

I’ve mentioned treble being just a tiny bit laid back from neutral on the AR6 but Zeus treble is definitely more laid back than the AR6. The AR6 has a sense of brightness and clarity through the treble when directly comparing with Zeus. However Zeus treble is still just as articulate and resolving, it’s just pushed a little further back in the sonic image. Whereas the AR6 carries some airiness and daylight from the upper midrange through treble, Zeus would never be described as airy.

Staging, Imaging & Separation
I’ve written with much emphasis on how special and unique the AR6 staging properties are with it’s life-like proportions and 3 dimensional presentation, however Zeus is also pretty special when it comes to its staging presentation as well. Zeus has incredible depth of presentation for an in-ear and is one of the deepest I’ve heard. Perhaps only the FitEar TG334 rivals this quality of depth. Zeus peals the layers back, exposing yet another layer of depth, after layer of depth. The precision of the layered presentation is Zeus most striking feature.

In direct comparison, the AR6 sounds distinctly wider and does a more precise image from left to right, which also leads to greater feeling of space and air between instruments. While both exhibit excellent height, the AR6 height is more proportional to its width and depth, whereas Zeus is definitely taller than it is wide. The AR6 depth is a realistic depth that is, again, proportional to its width and height. Zeus is more mind blowingly deep. It’s depth jumps off the sonic scape and instantly wows you. The AR6 staging prowess is more subtle in comparison and is less noticeable in noisy environs than quite environs, at least thats how my brain is interpreting what I hear.

AR6 mojo wooden table


The AR6 rivals anything top of the line being put out by anyone. Period. I’m seriously in awe of its presentation and I haven’t been this excited about an in-ear since I first received the UERM. At a starting price of $950, the AR6 is a veritable steal in the growing landscape of flagship custom in-ears, not to mention Mike’s attention to customer service is one of the best around.

For more product information visit Perfect Seal Laboratories at:

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  1. Awesome review with great detail and useful comparisons as usual! Loved it. The AR6 is definitely something I want to try out in the future if I ever get the opportunity.

    Liked by 1 person

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