Warbler Audio's Prelude CIEM- a labour of love
Apr 27, 2017 at 5:10 AM Thread Starter Post #1 of 220


Headphoneus Supremus
Jul 11, 2009

Normally, when one picks up the phone at 3am, it’s an emergency. Unless the twin towers have been attacked again, or someone’s in a life-and-death situation, you jolly well wait until morning. The mad scientists at Warbler, though, live on 3am calls to each other. I don’t know about you, but in my world that’s an unfriend you on Facebook type of scenario, which is obviously even worse than unfriending you in real life.

But perhaps it’s for the best that Tahsin, Baran and Hasan, three friends and fellow audiophiles who came together to start Warbler Audio, did not end up waiting till morning for all their calls to one another. After all, they’ve already spent five years (!) developing their one and only IEM. Imagine if they worked normal work hours- it might have taken a cool dozen years! In the process they’ve tried single driver designs, multiple driver/crossover designs, acrylic shells, silicon shells, acrylic shells again… During one particularly passionate 5am session, they even went full caffeine crazy and coded a programme to simulate effects on sound from changes in crossover design.

I first listened to a prototype of their IEM about a year and a half ago, and in the meantime they’ve revised their designs a few times based on feedback. After all of that experimentation, they’ve made an incredibly bold and interesting choice, coming back to the most timeless design of them all. Single BA, available only in acrylic. Classic. No crossovers, no fuss. (Ha, so much for that computer simulation- see what I mean by crazy?)

Personally, I’ve long thought that simplicity and purity is absolutely worth paying for. It is a lot harder to make a simple design sound good, so when I find one that works, I go all gaga. In theory, single driver IEMs present a more realistic sound, better coherence, and more realism and naturalness. Without multiple crossovers to cut up the audio signal, and without the need to carefully match paralleled drivers (each of which introduce micro-distortion since matching can never be puuurrfect), what you end up with is a design that has the potential to be extremely pure, resolving, and realistic.

But what makes their single driver so unique, so different from any other single driver? What took them five years to get here? There are no crossovers to tune; no drivers to mix. How do they make it sound so special?

That, unfortunately, are trade secrets that they’ve refused to share. But they gave an example- did you know that the angle at which the driver fires into the tube matters? They’ve tested thousands of such mundane variables over the past few years, and it’s all crystallised into this single product.

This is Warbler Audio, and here is their first IEM, the Prelude.

IEM: Warbler Prelude (click to go to their website)

Form Factor: Custom In-Ear Monitor

Damage: $1099 USD

Type of CIEM: 1 BA Driver


Interview with Warbler Audio

The Team

Tahsin is a Mechanical Engineer. He works in the Turkish Scientific and Technical Research Institute. He has been in this hobby for many years, and has built and created many IEMs, even taking special acoustic lessons during his university days. Apart from this hobby, he is also into special and unique pens, whiskey and cigars.

Baran is an admin of a forum website about audiophile equipment in Turkey. He has also been in this hobby for many years. He is in charge of Warbler Audio's market relationships and supplying goods for the company. Baran was also one of the chief testers/ listeners for their first IEM.

Hasan is an Electrical Engineer. He is also an admin for the aforementioned website. He is in charge of customer relationships.

How did you guys get started?

The story of our Prelude starts when this squad got together all into this hobby. Our engineer friend Tahsin had a big curiosity about how to build these kind of monitors and started to search every available information about them. He studied what he found on internet theoretically for a long time and also spent huge time on head-fi thread about home-made IEMs. Eventually he starts the preparations to build what he has in his mind. His first results were actually created in his university dorm and they were his own words "big disappointment". However he never called the white flag and worked continuously on them. He never gave up and started to improve the design. Hasan and myself were aware of his efforts but we didn't actively join in the process, yet. Then Tahsin created a prototype that he was satisfied and wanted us to give it a listen. After listening to it, we as friends started to work on this whole idea seriously and gave our focus to the job. They were the first steps of what Warbler Audio is right now.

Why a single BA design?

The first design was 3 BA and the shell was a silicone one. Through time we changed it to acrylic shell and the driver count was reduced to first 2 then 1. I was the one who is responsible about market relations and I was strongly against the idea of making it a single BA design since it will face bias unfortunately. Also marketing a single BA in the world of many multi BA monitors will be a difficult job. However the end result was much better in terms of sound quality so we all eventually accepted the fact that it will be a single BA design. We think when people see our Prelude and they would prejudice it and say it is an empty shell or design. We would like to let people know that through this 5 years, literally thousands of cross-overs were tested and eliminated in all 3-2-1 BA designs. There are thousands of components that were tested during R&D stage. The components that were end up NOT being in Prelude has a reason for it. After 5 long years, the design is optimized and shaped this way and everything in it or not being in it is on purpose.

OK, so the sound is great. What are your thoughts on crossovers now, having tried so many?

Especially on 2BA designs, we tried both extremely difficult and extremely simple cross-over solutions. Some of the solutions we found were used in other companies’ innovations, though it has no connection with us. Some other solutions of course stays in our hands at ready.

Working on those prototypes made us realize the secret things that has an effect on how balanced armatures work and their performance level. One of the most interesting cross-over we had with 2BA was working like 5-Band EQ, 7 elements and had 2-Way. Obviously we returned back to simpler cross-overs :)

We wouldn't want to be misunderstood though, when we stated that a cross-over leaves a negative impact. We tried seriously a big number of prototypes and different cross-over setups. Through this we had noticed that while we are making changes on cross-overs, we were just simply taking one positive thing and relocating it to some other area. This way of solutions were destructing the coherence of the sound. We didn't want to build something without integrity through whole FR. Moreover we think you already see that the Prelude has completeness, all of the frequencies are in harmony with each other.

The stuff other manufacturers talk about can be found in textbooks. For example some may be seen in "High Performance Loudspeakers" by Martin Colloms. Multiple crossovers are explained in books, but to give an example, the Spiral Ears SE5's performance isn't determined by just multiple crossovers, rather by the tweaks and the quality of the components. So, there's no rule that "more crossovers=better", just as there's no "less drivers=better". An earphone is made great by its engineer :) In the single driver design, the tweaks we apply contribute to the performance. Likewise, if we say the fewer the crossovers the better the sound, it wouldn't be necessarily correct.

If I just put the same BA into an acrylic shell, would it sound the same as yours?

It is impossible for others to get the same sound we created with the very same BA. We are actually very comfortable about this. People who seen the CIEM may think it is creatable, however there are really too many unseen and sensitive parameters that remains hidden. Just like we stated earlier, the Prelude is no random made CIEM. It has 5 years of R&D behind it. Actually the production stage is a lot more difficult than a multi BA design thanks to its extremely sensitive structure. You can compare it to Patek Philippe watches. Every detail has a sensitive, thin setting to it. Even in some standard procedures we went out of the standard ways to get the better sound. One of the reasons that we trust our R&D so much is that it is filled with "non-standard" applications. Many of our idea were found ridiculous by some people actually.

What are your future plans?

We want to create a universal IEM that will has a killer price/performance ratio. This will be in our plans for future. We already got some work done about it. Apart from this, we are also interested in building a DAC and cables too. We have some units that are only a prototype at the moment. However the whole process goes slowly so don't hold your breath right now.


The Sound

The Prelude has a few incredible strengths. It is really good at portraying each note in a self-contained, rounded fashion. Think of a good hybrid amp- the lushness of tubes, with the precision of solid state. Like a quality tube amp the Prelude is also baby-bottom smooth, without any graininess. It is also good at avoiding unsightly peaks in the response. The combination of these last two traits means that the Prelude really enjoys being ridden by the seat of its pants. Crank the volume up to 100, and go paint the town red. It doesn't get grating on the ears at these loud levels, and in fact it is when it is played at the loudest levels that the Prelude shines the most. Probably not a surprise, that the Prelude also easily passes the pop test, as in, 'does it make heavily compressed, overly-loud pop music sound like crap'? Well, no. I really enjoyed pop music from these. Even more impressive, it may be one of the best IEMs I've ever heard straight out of my iPhone. It's incredible how many otherwise splendid IEMs sound like nonsense from my iPhone. Kudos.

Male vocals and the lower mids are where the Prelude finds a spiritual home. For a long time I was confused about the Warbler, because female vocals sounded a bit off, and violin pieces actually sounded warm enough as to almost seem like a viola. But then I'd put on some cello, some male vocals, and damn if it didn't sound incredible. After more testing, I now think that the Prelude has a gorgeous lower mids presentation, but the upper mids sometimes suffer from a lack of bite and incision. This is particularly obvious in string instruments- violin, guitar- but also female vocals. If hair-raising upper mids are what you live for, look elsewhere.

But in place of the sinewy, thin strands of detail, the Warbler presents gorgeous tonal colour. Like clouds in the sky that come together, break up, and move on, this IEM portrays ever-changing shifts of tone from note to note, and sometimes even between notes. Pay attention to the flavour of the note as it passes through your ears. You may lose some texture with the Prelude (I'll get to an example with violins later), but in return you'll get bitter, sour, salty and spicy all in one.

The treble quality is ethereal, but detailed and real. The separation in the music is really good, and I've happily encountered that 'hmm, I've never heard that before' sensation that we audiophiles covet when hearing familiar music. What is this hobby, if not the continued rediscovery of new facets to the music that we enjoy the most? Depth perception is also very good, and the overall balance of the IEM works well. Bear in mind though that this is a relaxed, musical presentation, which will surely have its lovers, but probably won't suit everyone.

About the texture on violins: I definitely would have loved a bit more bite. I used to play the violin, and particularly prize the tension and friction that you should be able to feel as the bow is pulled against the string. I did not quite get that with the Prelude.

And then we get to the bass. Speaking to the fine folks at Warbler made it clear that they drew at least some inspiration from Spiral Ears. The SE5 Ultimate was sort of the poster child for size doesn’t matter, coming out tops in my first Fit for a Bat shootout despite being half the weight of many others. So it made sense why they’d cite it as an example. But Warbler also pointed to how the SE5U utilized many techniques that went beyond the obvious (like driver count) to get to its sound. For example, despite an overall bass-lite presentation, the SE5U had great quality nethers, with extremely seductive bass decay that I’d previously heard on no other BA IEM. The Prelude’s bass reminded me a lot of the SE5U. Beautiful quality, especially with the decay- in fact it may even have gone one better than the Spiral Ears in this regard. Detail and the timbre of the bass itself were also top notch, although if one considers the SE5U bass-lite (and I do), then the Warbler would probably qualify as downright aneroxic. Think hors d’oeuvres, not meat and potatoes.

In conclusion I rate the Prelude especially highly for its strong performance when driven loud, and for its remarkable performance from my iPhone. I also really loved the male vocals being exhibited here. These were truly top notch. I like to test male vocals with Eason Chan, who to my ears has an unremarkable voice, technically-speaking (he's no Mariah Carey), but nonetheless has a great ability to convey emotion. That just happens to be exactly the type of thing- subtle tonal variation reaching past one's mind into the depths of one's heart- that the Prelude excels in.


Trump vs Clinton. The Spiral Ears SE5 Ultimate is the king of airiness, serving up a wistful aftertaste to every note that lingers forever. In contrast the Prelude deliberately focuses on the primary colours, painting a beautiful weighty tone that pairs well with Frank Sinatra. The SE5U came in tops in two key categories in my first shootout: let’s look at each in turn. The SE5U treble places a strong emphasis on naturalness, smoothness and clarity. But while the Spiral Ears is a Bishop, the Prelude is a Knight- when one zigs the other zags. The Prelude is better on treble detail, ability to resolve complex treble passages and top-note speed. In soundstage the Prelude acquits itself relatively well, but still the SE5U edges ahead in imaging, staging size, and spatial microdetail.

For many owners, one of the key defining traits of the SE5U is its uncanny ability to present each note as an island, entire of itself. Every sound from the SE5U sounds like a raindrop, with well-articulated boundaries between wet and dry. Well, the Prelude comes close. It too is shaped like a water droplet- a slightly fuzzier one, but you can certainly hear what it’s going for.

The two have other similarities. Neither IEM is sinful. Both have refined, aged bass meant to be savoured and not chugged; and neither will give you a front row seat at your favourite metallic or rock concert (not that a true fan will need it, since I expect you on your feet). Both will instead appeal to a rather intellectual sort of audiophile. Classy.

In the end it may come down to this: what do you listen to? I’d pick the Ultimate for airy orchestral music, and the Prelude for Yo-Yo Ma. The Ultimate for live music, and the Prelude for Michael Buble. If you want to feel the venue, every nook, every cranny, few IEMs do it better than the SE5U. But if you want to soak in a bubble bath of emotions, sipping champagne and reveling in a dream of technicolour, then Warbler Audio’s Prelude is a fine choice indeed.


Bottom Line: An outstanding freshman effort from the Turkish company. They’ve spent a long time honing their sound, and it shows. Their price of $1099 also qualifies as a bargain these days in the world of high-end portable audio.

Score: 85-90 (Almost Perfect)
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Apr 27, 2017 at 6:22 AM Post #2 of 220
Interesting design choice. Can't say I didn't raise an eyebrow.

Well driver count wars aside, any other comparisons you can make? Perhaps with a Etymotic or HUM's Pristine? (Or maybe indulge me with a quick W900 side-by-side )
Apr 27, 2017 at 6:47 AM Post #3 of 220
They first sent me a prototype two years ago in a solid white shell. I had no idea how many drivers it had, and my first feedback then was already rather positive. Only later did they reveal to me that it was a single BA driver.

As for more comparisons, probably won't have time at this point, on a schedule with other IEMs. I do know that there are other people who have this IEM though so hopefully they'll chime in.
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Apr 27, 2017 at 10:20 PM Post #5 of 220

The Prelude never sounds like "only a one driver", instead it makes you think, "only from a one driver!"
Apr 28, 2017 at 4:10 PM Post #9 of 220
Very exciting news indeed! Read the review twice since yesterday and I'm tempted to get these as my first CIEM.

Looking forward to learn more about it's performance with rock and metal music.

Any ideas about it's sound signature compared to etymotic xr?
Apr 29, 2017 at 10:27 AM Post #11 of 220
Sorry don't have the Etymotic.
May 30, 2017 at 6:12 AM Post #12 of 220
great review jelt
Jun 1, 2017 at 10:02 AM Post #13 of 220
Thank you! :)
Jun 17, 2017 at 4:54 AM Post #14 of 220
Someone else had the chance to try or test the prelude ?
Just want to know .
Jul 7, 2017 at 11:09 AM Post #15 of 220
bump , this is now officially a top-5 ciem in @flinkenick TOTL shootout

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