Warbler Audio Prelude

General Information

The Prelude is Warbler Audio's debut custom in-ear monitor. Sporting a single balanced-armature driver with a number of unique in-house tweaks, the Prelude mates flagship performance with a beautifully organic tone and a supremely accurate timbre - redefining what a single mini-transducer is capable of.

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Headphoneus Supremus
Pros: Beautifully natural, organic and life-like tonality
- Textured and coherent images
- Melodic, vibrant and arresting upper-mids
- Excellent bass timbre
- Smooth yet articulate treble
- Decent stage organisation and background cleanliness
- Strong build quality
Cons: Subpar bass and treble extension
- Minimal sub-bass rumble
- Soundstage isn't the largest
- May lack headroom, air and supreme cleanliness (esp. to those accustomed to the hi-fi sound)
- Price (esp. to those who value tonal accuracy less than technical ability)
DISCLAIMER: Warbler Audio provided me with the Prelude in return for my honest opinion. I am not personally affiliated with the company in any way, nor do I receive any monetary rewards for a positive evaluation. The review is as follows.

Warbler Audio is a Turkish in-ear manufacturer, relatively unknown until their sky-rocket to stardom throughout the back end of 2017. Finally making their debut in a review written by our very own jelt2359, it wasn’t long before talk of their premiere product – the Prelude – spread like wildfire. It ranked 4th overall on flinkenick’s Ranking the Stars TOTL shootout, and quickly became a favourite amongst midrange enthusiasts worldwide – all the result of six years in R&D and one, exceptionally-tuned balanced-armature driver. To revisit the Prelude’s long and arduous birth; you can read Jason’s interview with the company here. But history aside, the Prelude has been impactful for a reason: A fusion of vintage sensibilities and modern technique, resulting in an IEM that captures both methodical skill and timbral beauty.

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Warbler Audio Prelude
  • Driver count: One balanced-armature driver
  • Impedance: N/A
  • Sensitivity: N/A
  • Key feature(s) (if any): N/A
  • Available form factor(s): Custom acrylic IEM
  • Price: $1099
  • Website: www.warbleraudio.net
Build and Accessories

Warbler Audio’s Prelude arrives in a Peli 1010 case alongside a Linum BaX cable, cleaning tool and desiccant. Like I’ve expressed before, this is the bare minimum as far as packaging and accessories are concerned. I attribute the lack of flair to Warbler Audio’s infancy. But, considering the impressive build quality they’ve achieved with their debut, I’d love to see them apply the same discipline towards visual presentation. Branding has become as important as ever nowadays, with many companies worldwide offering spare cases, soft pouches, microfibre cloths, etc. I appreciate Warbler Audio’s immense focus towards sound, but presentation is something much worth considering down the line.

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Despite their workmanlike approach towards packaging, Warbler Audio have certainly flexed their muscles in build. My Prelude is an exceptionally-crafted piece; bested only by a select few in my collection. Apart from the multitude of colours available on their webpage, Warbler Audio allow customers to pick from a wide variety of woods among other miscellaneous materials – such as the one on their Instagram page here. I opted for Padauk wood faceplates and glittered black shells, topped off with Warbler Audio’s sterling silver logo; a gorgeous combo if I may say so myself. The only knack I have with regards to build is a lack of symmetry between the left and right units, but that could be attributed to the quality of my ear impressions. Plus, I can hardly call it a fault if fit and finish are perfect either way.


The Prelude is devoted to tonal accuracy, comprised of elements which – above all – exist to form a linear and organic signature. To this end, the Prelude compromises. Its stage is neither the widest nor deepest you’ll find (impressive nonetheless for a single-BA in-ear). But surprisingly, it hardly ever feels claustrophobic. Separation and layering impress, bolstered by a clean background. So, its intimacy translates to richness and musicality once you acclimate to its size. Despite the Prelude’s warm air (as a result of modest treble extension), its single-driver config allows for an even, coherent response – imbuing the Prelude’s soundstage with well-placed-and-resolved instruments fanned throughout.


Balance is truly the Prelude’s forte. The Warbler IEM provides just enough of everything to achieve an even-handed response; compensating for transparency by ensuring no frequency range ever masks another – an aspect eschewed nowadays in favour of extra sparkle or impact. But because of this devotion towards organicity, the Prelude represents the antithesis of pushing details in your face. It wilfully places its focus on other aspects; the tone of the bass instead of rumble, the melodiousness of the upper-mids instead of transparency, the speed of the treble instead of the clarity or edge. This will appeal to listeners who appreciate tone, realism and unity, but it’ll also repel those searching for the pinnacle of openness and air. Crowd pleaser it is not, but its beauty is undeniable; life-like, defined and smooth.


Despite the Prelude’s reputation as a midrange maestro, the merits of its tuning truly begin here – one of the most tonally correct and life-like bass regions I have ever heard. Rather than any single superlative trait, it’s an outstanding mix of segregation, resolution, pace and timbre. No matter the genre or track, the Prelude consistently outputs dense, meaty and well-resolved punches, which then decay naturally into the in-ear’s black background like a heart beat; realistic in pace, fibrously textured and organic in timbre. Much like the treble we’ll explore soon, the Prelude balances impact with decay; lingering just enough to convey palpable weight and proper texture. So, instruments here are full-bodied, dense and warm, but always defined and never intrusive; present, but neither bloomed nor congested.

Again, this is because of a linear transition between the mid- and upper-bass. Both work in tandem to ensure the transitions between impact and decay are as seamless as possible, and it’s constantly impressive. However, an element noticeably missing here is sub-bass extension. The Prelude’s low-end lacks a true, visceral grunt. Now, minimal sub-bass may benefit exclusively in genres like indie-folk, classical or lounge jazz, but it’s a sensation sorely missed in more synthetic music. Timbre is something the Prelude slaves to perfect, and justly so, bass tone is impressively realistic. Although it lacks the physicality required to fully replicate an upright bass, the instrument’s warm and woody shades are left fully intact. Rich, heart-y and gossamer, this is a bass response that lacks neither charm nor personality. It won’t win over any bassheads any time soon, but its musical, melodic presentation is a beauty to behold.


Arguably the most esoteric element of music, Warbler Audio does not disappoint. A hump exists throughout the Prelude’s vocal range, manifesting in the form of dense bodies you can feel throughout the stage. Instruments are solidly founded and physically present, paired with an organic tone that colours them to a realistic hue; lightly warm yet melodious. An elegance constantly underlies its delivery – resulting in a mid-centric presentation that’s neither honky nor forced. So, midrange focus does not translate to an overt forwardness. Instead, the Prelude maintains great linearity between the bass and treble, which – in turn – imbues it with solidity, resolution and a seductive timbre throughout.


The Prelude boasts full-bodied and well-articulated notes. Instead of relying on the upper-treble, the upper-midrange becomes key in preventing instruments from sounding dull or veiled. Like how lemon juice wakes up a pasta dish, a lift along 2-3kHz adds this liveliness to vocals and instruments alike. Lead guitars are crunchy, fuzzy and warm, and vocalists are as gruff and chesty as they are clear and sweet. This is finished with a 5kHz dip for smoothness over clarity. Adhering to more classic sensibilities, the Prelude relies on linearity, density and speed to form its midrange; powerful, vibrant and soulful, if not spotlessly clean. Ultimately, a sweeping emotional response is what the Prelude was made to achieve, and its gorgeous, humane midrange has done just that; an instant classic in presence, authority and organicity.


Despite minimal extension, the Prelude’s treble is exemplary in smoothness, tone and speed. A lower-treble dip renders it pleasingly rounded; feathered in nature. And yet, the pace at which treble notes appear and disappear prevents any congestion or sluggishness from appearing; maintaining a sense of attack at all times. The Prelude’s rise into the middle-treble draws clarity, but contrast between notes and the black background is merely okay. Regardless, the Prelude’s highs maintain coherence; with no egregious peaks for extra sizzle. From the evenness between crash and sizzle in cymbal hits, to the extremely satisfying snap! of snare drums, this is a top-end as clear as it is cautiously subtle.

In timbre, the Prelude reliably delivers. A warm tinge affects vocals and instruments alike – defined by how seductively and easily they come across despite compromises in clarity and air. So, instruments are neither artificially bright nor overtly crisp. Done improperly, this may lead to a dark image, a congested midrange or a boomy bass, but the Prelude never buckles – relying on speed to deliver detail in the most graceful way possible. But again, Warbler’s top-end is not a crowd-pleaser. Enthusiasts looking for ultimate sparkle and cleanliness will leave dissatisfied with the Prelude’s more laid-back approach. But, if you can appreciate treble as more than just a detail dispenser – rather, as deserved of tonal appreciation as any other – the Prelude’s top-end will impress; a rare mating of timbral elegance and technical aplomb.

Select Comparisons

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Empire Ears Phantom

The Phantom is an in-ear tuned with similar principles in mind: Equal balance between tonal accuracy and technical performance. So, the two share quite a few similarities; particularly in priority and presentation. Both IEMs could be considered mid-centric, but the Phantom has superior balance across the band. This is because of the latter’s greatlysuperior extension; creating a stronger foundation in the sub-bass, as well as a larger, more breathable stage up top.

The Phantom’s low-end is technically stronger by a significant margin. Excellent extension imbues it with a masculine grunt, as well as stronger physicality. Bass lines feel satisfying whilst maintaining an organic tone, while the Prelude focuses on hearing the bass. Amongst their BA brethren, both monitors display excellent texture and resolution. Because of the added sub-bass content, the Phantom’s bass is thicker and heftier, whilst the Prelude’s has a clearer sense of articulation – and decays a tad faster as well – to compensate for its light touch; more thwack than thump.

In the midrange, the Prelude’s presents a lighter, wispier image, though both monitors share a warm and melodious tone. The Phantom has a fuller lower-midrange, which renders harmonic overtones more clearly; adding meat to vocals and instruments alike. The Prelude’s presentation is more effortless and smooth, while the Phantom’s 6kHz peak gives it a slightly tense bite. Though because the Prelude has an upper-mid-bias, vocal delivery gains excellent refinement, while the Phantom’s finesse gives it the edge in transparency and resolution. Finally, the Prelude’s lighter bass gives it a greater sense of speed, whereas the Phantom’s midrange is almost showcase-like; prevalent, well-defined and organic.

The treble is where the Phantom – once again – displays its technical prowess. Superior extension constructs a larger, blacker and more stable stage, where sonic images are better defined and precisely placed. The Prelude – despite its warm air – displays admirable organisation and separation, but the Phantom’s stronger background gives it a more breathable ambience; less intimate yet equally engaging. The Phantom peaks at 6kHz, while the Prelude’s lies closer towards 8kHz. This gives the latter a tizzy-er and more feathered edge, while the former articulates in a more rounded, transparent and clear fashion. But, the Phantom is more prone to stridence with subpar material and/or pairings.


Avara Custom AV2

The AV2 is another mid-centric, for vocals IEM. Its accentuated, full and linear midrange invites density, organicity and refinement within its vocal presentation; resulting in notes that feel complete, well-textured and natural in tone. Like the Prelude, the AV2 maintains an intimate stage, as well as a bias for width over depth. Superior treble extension gives the AV2 greater stability, as well as a blacker background. As a result, the AV2 is slightly more transparent. But, the Prelude’s superior balance overall (i.e. coherence or linearity) endows it with stronger separation and stage organisation.

The AV2’s low-end extends further than the Prelude’s; displaying decent sub-bass presence and greater physicality. However, when it comes to resolution, tonal balance and pace, the Prelude comes out on top. Excellent speed articulates each of the Prelude’s throbs with excellent clarity, with sufficient decay to accurately portray timbre and texture. So, this presentation sounds more multi-faceted. The AV2 has a darker bass; more foundational than melodic. It’s the more satisfying bass with synthetic music, while the Prelude portrays bass instruments with striking realism.

The AV2’s midrange – like the Prelude’s – is dense, meaty and rich. However, a fuller lower-midrange highlights its chesty qualities. Vocals and instruments alike sound more gruff and forwardly-placed, while the Prelude’s delivery is sweeter by comparison. This extra zing gives the Prelude a clearer tone, while the AV2’s 7kHz peak gives it more bite. Both monitors possess a 5-6kHz dip; more obviously on the AV2. As a result, it articulates in a smoother manner. But when paired with the 7kHz peak, it sounds slightly less coherent – more diffuse – compared to the Prelude. The Warbler Audio premier delivers its instruments as a cohesive whole, while the AV2 compromises this (slightly) for clarity and edge.

Both the AV2 and the Prelude share a relatively linear treble. Though, the AV2 has a slight lift towards the upper-treble, which gives its top-end a more neutral tone. Both IEMs maintain warmth in the midrange, but this lift gives the AV2 an increased sensation of space and air. The Avara Custom IEM also has the edge in treble extension, better defining the dimensions of its stage. However, the Prelude’s superior coherence maintains a greater sense of refinement, as well as a more realistic timbre. Instruments are less aggressive (even though they’re already smooth on the AV2), yet the Prelude resolves them with greater effect – a result of its evenness across the band and the black background it brings with it.


The Warbler Audio Prelude represents a devoted pursuit towards smoothness, realism and refinement; a true outlier in the age of sparkle, dazzle and pizzazz. Its tonal triumphs aren’t without technical shortcomings. But where it counts, the Prelude has in spades. Linearity, power, texture and pace are the four cornerstones that uphold the Prelude’s natural timbre with great aplomb. Sheer transparency and detail will never take top billing, but sheer musical intent has never been so clear. Those capable of appreciating the warm, vibrant hues of yesteryear will fall entranced by what the Turkish bird has to offer: A strong, sultry and soulful representation of what music could – and should – feel like.



Headphoneus Supremus
Pros: - Beautiful, natural tonality
- Utterly revealing
- Amazing vocals and treble
- Great left-right separation and imaging
- Comes with a nice Linum BaX cable
Cons: - Sub-bass shy => not advised for ‘hardcore bassheads’
Definition of prelude in English:
1) An action or event serving as an introduction to something more important.
2) An introductory piece of music, most commonly an orchestral opening to an act of an opera.

So, the Prelude is Warblers introduction in the wonderful world of audio. And what an introduction it is!


The Prelude got my full attention when it ended in @flinkenicks totl IEM shootout at the #4 position.
That was quite a remarkable accomplishment imo, regarding its relative low (well, at least compared to most of the other contenders) pricetag of $1099. And the fact that it only had ONE balanced armature driver a side!

Now, if there ever was an IEM that put the drivers war in a completely other perspective for me, it absolutely was this ONE!
Only ONE single BA driver a side? You’ve got to be kidding, right? Could it possibly sound that good? I just had to found out for myself and was lucky that I could get the Prelude on a loan for a couple of weeks soon after that.

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The answer was: YES! It sounded that good! As a matter of fact it sounded indeed better to my ears than most IEMs, carrying many more drivers inside, that I had heard untill then. It didn’t took me much listening time to realize that this truly was a very special ONE and that I wanted it in my collection. And so I contacted the (very friendly) guys at Warbler, which resulted in an imo beautiful (thanks @hamhamhamsta for the inspiration) design later on…

Btw, for more background information regarding the Preludes technical design or the guys who developed it, please check this excellent review by @jelt2359, which was also the start of a dedicated Prelude thread itself.

The Prelude came in a nice Pelican 1010 case, incl. a (very thin) Linum BaX cable, a 3,5mm to 6,3mm adapter, cleaning tool and a small drying pellet.

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When I got it, I almost immediately picked the Ares II cable for the Prelude, as I already knew (thanks to the loan period, when it came with that cable) that they had excellent synergy.
And even from a $350 dap like the Opus #1, the Prelude already sounded fantastic to my ears!

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Just recently I thought ‘OK, let’s try that Linum BaX stock cable for a change’ and I was surprised how good that ONE sounded as well. Maybe not as extremely clear as the Ares II, but still pretty close, with a wonderful smooth and full bodied signature. Let’s also not forget that this is a $79 (= approx $100) ‘stock’ cable. So, the guys at Warbler certainly didn’t go for the ‘cheap / let’s save us some dollars on a cable’ route.

Taking the sq up to 'top notch' level, from a RedWine modded AK380 Cu :ksc75smile:
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Now the main question: How does this little birdie sing?
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This was what I read on some website and imo it would essentially do as a basic, but pretty accurate signature description:

''Equipped with only a single balanced armature on each side, the Prelude is tuned specially for tone, with a timbre that is considered as natural. The Prelude offers a velvety smooth sound that has powerful, deep, emotional vocals that is completed with a mid-range presentation that sounds as if the Prelude can present infinity number of layers in this spectrum of sound.

With it's beautiful timbre and smooth, natural presentation, the Prelude doesn't aim to please the crowd, but to entice specific audiophile users that want a pair of in-ear monitors that allows them to forget about seeking the utmost details and transparency, but to simply let the music flow into their heart.''

Or to elaborate on that a bit further in my own words:

Do you know the feeling that you’re listening to music and you get so involved, that the rest of the world seems to disappear and you simply become ONE with the notes surrounding you?

Have you ever seen the movie ‘Magnolia’ by Paul Thomas Andersonn? Now that ONE did put emotions in the spotlight, didn’t it?
Eeeh what? You saw it and it didn’t move you at all in some kinda way? Well, in that case I’ve got a newsflash for you: 'Congrats my friend, you’re an android!' :wink:

Now, do you also know/remember the song ONE by Aimee Mann from that same movie?
There’s a lot of emotion in that song and Aimees wonderful sweet voice. And I doubt that any other iem brought me closer to the core of that emotion in that voice than the Prelude did.

So, if ONE is the loneliest number that you'll ever know’, how to explain that an only ONE driver IEM can make me enjoy music in such an impressive way? Could it be because there’s nothing more cohesive than the number ONE?
What is it exactly that makes the Prelude such an excellent sounding ciem?

Imo it’s the clarity and superb (also left-right) separation that makes you aware of all the (micro)details that are in the music. ONE of the most used clichés is probably ‘It made me hear things that I never noticed before’. Well, excuse me, but that is exactly(!) what this IEM does for me...the Prelude is just detailed on an almost scary (micro)level to my ears. No matter how hard the microdetails try to hide within the music, the Prelude will hunt them down for you.

Soundstage is decent imo, surely not the widest or most holographic that I’ve ever heard, but still realistic and slightly ‘out of your head’.

However: this is NOT an IEM for addicted hardcore bassheads! For my taste there’s enough (especially mid-bass oriëntated) lows and it’s a high quality (very detailed and tight) bass as well. But don’t expect too much sub-bass on a bone rumbling level.

On the other side of the spectrum, the treble is ONE of the best I’ve ever heard. Never harsh, smooth but still always revealing. Instruments like cymbals or bells sounded crystal clear to my ears.

But ONE of the most important ingredients that makes the Prelude sound so good/special is its (natural) tonality. Instruments and vocals sound very realistic to my ears. And that beautiful timbre is probably the reason that gives the Prelude its slightly warm signature and makes vocals sound so wonderful emotionally loaded at the same time.

A short comparison with some other, also priced at $1100, BA driver IEMs that I own(ed):

Warbler Prelude vs the 5BA Campfire Audio Andromeda
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The Andromeda is usually my ‘on the go’ IEM. Because it’s such a small universal, it’s easy to put in / take out whenever you travel, or go to public places. The Andro beats the Prelude in soundstage and has a more bass heavy signature, but I like the Preludes treble, mids (especially vocals) and overall signature better. Where the Andro has a fun and dynamic tuned signature, it simply lacks the beautiful and natural timbre / tonality that the Prelude delivers.

Warbler Prelude vs the 8BA Custom Art Harmony 8.2
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The Prelude delivers more and imo better treble than the H8.2, where the H8.2 has noticeable more (sub)bass in its signature. The H8.2 sounded pleasantly smooth and relaxed, but less detailed to me than the Prelude.
Soundstage wise (based on memory) I don’t think they’re that far apart.

The Prelude sounds more revealing to my ears, with better left-right and instrument separation. Although the H8.2 sounded very natural and coherent, and I really liked its lows, it sometimes just lacked some ‘bite’ to my taste. Where the Prelude always makes me feel like I’m on some kind of musical adventure. Discovering new nuances and emotions in the music itself down that road.

OK then, ONE final song called ONE (sorry to all Metallica fans, as I chose another ONE) was written by some, maybe not so well known, obscure little Irish underground band. Later on another version appeared, ft. Mary J. Blidge.
But the song never touched my heart and soul, like the way it did when I first heard this (bare naked, but so sincerely sang on an emotional level) version from the legendary ‘Man in Black’ himself:

Just listen to it, and if you ever get the chance to check this version again, with the Prelude in your ears, then you’ll probably agree: the Warbler Prelude is a beautiful tuned IEM, that is able to capture the emotion in/behind the song! But beware: once you’ve heard it yourself, it might also capture your heart. And chances are big that you won’t be able to resist ordering ONE yourself after that experience.

So, should I rate the Prelude, out of ‘theme consistency’, with just ONE star? Yeah, right! :grin:
Maybe that would make sense in an ‘upside-down’ universe...but here in this Head-Fi universe it will get the full, five star, ranking from me. Without ONE single doubt.

Or, to put all the above in just TWO words: BRAVO PRELUDE!!!

Thanks for reading and happy listening to all of ya’ out there!
Ok so why you can't create an universal variants of a custom made iem and why now warbler won't use the 1 ba setup that have take them 5 yrs to research into their lineup now at Revostage😑.
'...and why now warbler won't use the 1 ba setup that have take them 5 yrs to research into their lineup now at Revostage'

Good question, and I don't have the answer (as I don't work for them and had no contact with them after I bought the Prelude) to that. I didn't even know about the existence of Revostage (and their new line-up) until now, so thanks for the heads up! :)


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