Brainwavz Koel

General Information

The Koel are a lightweight and ergonomic earphone, created to sit comfortably in the ear for true fit-and-forget experience. The unique shape has been designed and printed in-house using state-of-the-art 3D resin printers and assembled using components from USA and Europe. We include a wide range of ear tips to give you perfect fit for the ultimate in sound quality and natural sound isolation, plus the included memory-formed cable make for a truly comfortable all-day listening experience.

These Balanced Armature in-ear-monitors (IEM’s) play host to one of the finest earphone drivers around. They are tuned to produce a balanced and accurate sound signature, with little to no colouring, presenting a truly genuine audio experience that lets you hear the music as the artist originally intended.

The Koel are a great introduction to the world of refined audio, now you get to re-discover and experience your favourite music all over again.

Brainwavz unique approach to manufacturing means we are always in control, quick to develop and bring products to market, continuing the Brainwavz ethos of delivering the high-end audio experience to everyone at affordable prices.

Latest reviews

Pros: -Damn Good Mid-range
-Fits Perfectly (to me)
-Good Carrying Case
-Smooth tonality
-1 Year Warranty
Cons: -Lacks details
-Lacks extension on both ends
-Bad stock cable
-Not that competitive in the price tier
Thank you Brainwavz Audio for letting us give our honest take towards the KOEL. Given that the review unit is from Brainwavz Audio and is free of charge, it doesn’t affect the honesty and integrity of this review.

The Company

Brainwavz provides high-end earphones specifically designed for high-quality sound and tailor-made to provide the user with a solution that can be used across a wide range of audio genres and styles at affordable prices. Brainwavz believes in the idea that sound is a deeply personal experience, and strives to provide users with earphones that match their personal inclinations, to inspire with intensity. The Brainwavz name is known in many countries across the globe, and the company is continually committed to providing the best products at the best value. This is what they stated in their website but hey, Brainwavz has been in the industry for years and they already build a good reputation in terms of build and sound quality in fact the B400 was a hit!

The Brainwavz Audio KOEL

The KOEL is a single BA entry level IEM from Brainwavz, I think it is their take to rival the exponential growth of Chi-fi IEMs under 5000 Pho (100 USD). It is 3D printed with resin as the main material, the build quality seems to be alike with the Brainwavz B400 which I really liked. I wholeheartedly agree that they tuned the KOEL to be natural and to attain almost no coloration, timbre is kinda nice and it may sound bland for some. It is priced at 2500 Php (50 USD) and I honestly believe that it is pretty competitive, it just that majority of consumers in this price segment wants warm or V shaped sound signature. It comes with 2 colors, first is “stay frosty” which is the transparent one and second which is the one I’ve got, the “cosmic black”.

Technical Specification:

  1. Drivers : Single Balanced Armature
  2. Rated Impedance : 30Ω
  3. Frequency Range : 16 Hz ~ 22 kHz
  4. Sensitivity : 105 dB at 1 mW
  5. Cable : Detachable
  6. Cable Connector : MMCX
  7. Plug : 3.5 mm, Gold plated

Packaging is very minimal, if you don’t check their site you will not expect a high quality carrying case inside. Everything resides in the carrying case, IEM, cable, 1 pair of comply foam tips, 6 pairs of silicone tips, Velcro, shirt clip and paper works. I can honestly say that the packaging looks good despite being contained in a small box. There’s sufficient ear tips, and a commendable carrying case that majority of chi-fi doesn’t have.

Fit and Comfort

The fit of KOEL varies with the user, personally I did able to get perfect fit with almost any tips that I use, but for smaller ears I don’t think it will fit nicely with them especially that the nozzle is kinda short. With proper fit, there’s almost no sound leak especially when listening with average volume, isolation is commendable too. It is generally lightweight thus, listening for several hours won’t give any discomfort (at least for me).

I love IEMs and earbuds with midcentric to flat sound signature as I really love listening to vocals rather than instruments. My genre ranges from heavy rock, alternative rock, pop rock, acoustic, pop, jazz and folk. Majority of my test tracks are in 16 bit – 44 khz and 24 bit – 48 khz FLAC file and here is the list of my commom test tracks.

  1. Reese Lansangan – For the Fickle (background, female vocals and upper mids)
  2. Foo Fighters – Bridge Burning (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Treble)
  3. KATIE – Remember (Mid Bass, Mids)
  4. Ed Sheeran – Dive (Mid bass, Lower Mids)
  5. Norah Jones – Don’t Know Why (Upper Mids and Instruments)
  6. Paramore – Hard Times (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Treble)
  7. Led Zepplin – Rock and Roll (Imaging Layering, Bass, Instruments, Lower mids, Treble)
  8. Passenger – Coins in a Fountain (Mid bass, Layering, Imaging, Instruments, Lower mids, Treble)
  9. Aimer – Torches (Background, Upper mids)
  10. Ariana Grande – Raindrops (Background, Upper mids)
Sub bass feels roll off for me, 100 Hz below doesn’t have enough presence. It is recessed and lacks quantity too, making rumbles and riffs subtle and light, luckily it has good texture and resolves enough details. For the mid bass, it feels smooth and soft for me, it is slightly more forward and has enough attack and decay speed. The bass lacks presence, impact and rumbles but I can fairly say that it is smooth and easy to listen if you’re not looking for impactful and deep bass.


The star of the show here is the midrange, starting with lower midrange it is velvety with slightly forward positioning, male vocals and piano sounded good, no hints of dryness nor hollowness here. I can say that it is not that resolving but in exchange it is clean and smooth which is commendable. Upper midrange shares the same positioning as the lower midrange which is pretty forward, it is sweet and intimate making Norah Jones sing flawlessly, it is still smooth and still not the most resolving pair in its price bracket but listening to my favorite pop, folk and jazz tracks feels very engaging.

Just like the bass, there’s a roll off here as well, it is recessed too giving slight boost with depth as it compromise for the midrange being too forward compared to bass and treble. It is very smooth and has good amount of air despite being a single BA IEM, but sparkle takes a toll here, cymbals doesn’t sound energetic. Good thing it isn’t aggressive, no signs of peaks here but this wouldn’t suffice folks who loves treble.

Sound Stage and Resolution
Sound stage is on the intimate side here, I believe this is due to the midrange being a bit too forward, depth is decent while width and height is a bit cramped for my liking. Imaging and layering is above decent for the price, I’m surprised that even it has an intimate staging, it can be this coherent and accurate since base on my experience when there’s not much headroom and width, imaging and layering becomes sub par as well but that’s not the case here.

Sound Signature and Synergy
The KOEL offers an intimate and mid-centric sound signature, it has a forward midrange and recessed bass and treble. It is perfect for some but I believe that there’s a little population of folks who loves mid-centric tuning. I would love pairing it with bright/analytical sources since for me the bass of KOEL is forgivable but I really want more sparkle up top.

Hiby R3

Hiby R3 is a warmish source, pairing it with KOEL There’s some slight elevation on the bass but it still less forward than the mid range. Treble still sounded dark for me, it lacks extension and sparkle but it is airy enough and has more than decent attack and decay speed. Midrange sounds very good, it sounds full and has natural timbre on it. Sound stage isn’t special as mentioned above but it is decent enough with this set, I find the projected space to be small in general but it sounds natural and accurate enough for me.

Smartphone (Huawei Mate 10)
Extension on the bass was unchanged, quantity is further reduced while positioning remained the same as well. Midrange became slightly leaner but less resolving, it is still smooth but there’s a bit decrease in terms of lushness. Treble became a bit forward, extension didn’t improve for me but there’s some improvement in terms of sparkle. Sound stage isn’t impressive here, same goes to resolution.


I can’t compare them fair and square because the use different driver and the offer different sound signature, it is really rare to have an IEM tuned like the KOEL. Starting with bass, it is pretty obvious that the BL03 will take the win simply because it sounded more neutral, has better depth and impact. Midrange sounded sweeter and more natural in the KOEL, it may be inferior in terms of resolution but it has better timbre and fullness. Treble goes to BL03, it has more air, sparkle and extension as I find the KOEL to be much smoother which is kinda odd for a single BA IEM to have a dark-ish treble. Sound stage goes to the BL03 in terms of size but for accuracy of imaging and layering they are pretty close, the BL03 is a notch better too in terms of resolution since it extends fairly well on both ends.

The KOEL isn’t bad at all but if you want a better all rounder at slightly cheaper price tag then you should go with BL03 but if you want a new flavour, a mid centric IEM then the KOEL is a no brainer, it also have a 1 year warranty versus the BL03 with no warranty.

KZ ZS10 Pro

I can’t compare them fair and square because the use different driver and the offer different sound signature, it is really rare to have an IEM tuned like the KOEL. Starting with bass, the ZS10 Pro has better depth, impact and positioning but I prefer the smoothness of KOEL’s bass, still the win goes to ZS10 Pro. Midrange easily goes to KOEL due to its sweet and velvety presentation compared to the dry and recessed midrange of the ZS10 Pro. I’ll give the treble a tie, while they both doesn’t have the sparkle that I’m looking for but the ZS10 Pro slightly edged out the KOEL in terms of extension while the KOEL in terms of attack and decay speed as well as smoothness. Sound stage is better in ZS10 Pro in terms of Size while they are close in terms of imaging and layering. Resolution seems to be on par as well.


While the KOEL might not please everyone due to its forward midrange and average sound stage, it will be a nice gear for someone who wants something fresh as mid-centric IEMs are not that common in this hobby. Bass lacks extension and impact but it offers smooth and speedy attack and decay. Midrange has a commendable timbre, velvety presentation and intimate positioning. Treble lacks sparkle and extension but it is pretty agile and offers a smooth listening without treble spikes. Sound stage is average in terms of size but in terms of layering and imaging it can compete with similarly priced Chi-fi IEMs, resolution is average as well as it leans with smoother tuning. For the price I wouldn’t say that it is a steal like the BL03 but still it is a nice buy, a unique mid-centric tuning with nice carrying case and 12 months of warranty.
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Pros: Clear midrange, non-fatiguing highs, included Comply tips creates great seal and isolation.
Cons: Stock cable could be better, rather long body accounting for some discomfort
Communication is an essential component of a community and while we have our own way of communicating via different sorts of languages, other species also have their own particular form of communication. Birds for example communicate with each other by constructing either a sequence of drawn-out melodic or short bursting noises to convey whatever message they want to relay.

If you haven’t known it yet, the birds’ reference was in relation to the IEM that we will be realviewing now from Brainwavz Audio, a company that started way back 2008 and has already appeared multiple times on Audio Realviews thanks to their collection of ear pads options for various headphones. That particular IEM is the Brainwavz Audio KOEL, marketed as an “affordable audio excellence” set and priced at $69.50 (On sale for $39.50 as of 17/07/19). You can check the KOEL out in the official Brainwavz Audio website.

The KOEL is spec’d out with a single balanced armature driver with a 16Hz to 22kHz Frequency Response, 30 Ohm Impedance and a 105 dB Sensitivity. Will the Brainwavz KOEL sing and chirp as it’s marketed to be or will it just squeal and shriek like it isn’t supposed to be, let’s chime in to find out.

Packaging and Build Quality

The KOEL came in a much nicer packaging than I’ve been accustomed to seeing from a Brainwavz package, it now comes in a rectangular semi-glossy white sleeve with the KOEL name upfront as well as the highlight Comply ear tips and 24-month warranty that it comes with. Removing this sleeve reveals the gray matte flap box and the vibrant mix of colors that covers the foam cutouts that protect the textured hard case with a red zipper lining for that trademark Brainwavz appeal. Here’s a list of the included accessories that the KOEL comes with:

  • 6x Sets of Silicone Ear Tips (S M L)
  • Set of Comply Foam Tips T-100
  • Shirt Clip
  • Velcro Cable Tie
  • Instruction Manual
  • Warranty Card (12 month warranty)
The KOEL is made entirely of 3D-printed resin that either comes in the “Stay Frosty” or “Cosmic Black” colorways. The “Stay Frosty” colorway was provided for the realview and the main difference that it has against the “Cosmic Black” is that it has the Brainwavz branding in the faceplate whereas the other does not. Its shape resembles that of the famous Jelly Belly candies with a slight lip on the lower portion to provide added seal and isolation. It feels a bit uncomfortable upon initial use which made me tinker with the IEMs position on my ears longer than usual to get a decent seal and comfortable fit. The underside of the KOEL IEMs features a discreet L and R markings along with a single vent and a gold-plated MMCX connection. The nozzle is short with a narrow bore and a pronounce lip that worked great with tip rolling and securing the Comply T-100 foam tips as well as the included silicone ear tips.
The KOEL’s stock cable has no official specifications but is built solid, the black rubber insulation clearly hides a braided cable inside that has moderate tension making the cable a bit tangle resistant but retains folds easier as well and good thing there is a Velcro cable tie for that cable storage solution. The gold-plated 3.5mm plug comes in a 45° angle with great strain relief, same goes for the Y-split which now has a Brainwavz logo ending in a gold-plated male MMCX connector with an over-ear memory guide. There was minimal microphonic noise to be observed as well.

Tonality and Isolation
The KOEL sound signature diverges from the Stay Frosty colorway that was sent over for realview. The KOEL exhibited an overall warm sound with an emphasis on the midrange, an aspect that was somewhat showcased even in their BLU-300 Bluetooth IEM. I tried hard to use the silicone ear tips that was included and although I usually prefer silicone ear tips over full foams, the packaged Comply T-100 was just too hard to resist on being paired with the KOEL, it also gave the best seal and isolation among the ear tips that the KOEL came with. I used the Sony A46HN music player and the Sony CAS-1 via Foobar v1.4/MSI GF62-8RE for the duration of the realview outputting various FLAC files which would be mentioned along the realview.

Coming in with a slow burn, Jamiroquai’s Night Out in the Jungle in 16/44 FLAC was used for the low-end test of the KOEL. The sub bass lingers long with a soft thump and a slight touch of power and control. Bass drops that starts dropping on the earlier part of the track are borderline thin sounding, just a heave and those that seek a powerful and impactful low-end will feel displeased. The KOEL won’t go chasing bassheads for their approval with its presentation.

The KOEL’s midrange is its sweet spot. Michael Learns to Rock’s Sleeping Child in 16/44 FLAC glides through with ease and clarity. The lower midrange delivery has great body and has notable coherence with the midrange male vocals, coming off as articulate and engaging. The upper midrange performance was rendered in a breathy manner with a smooth extension and lively ambience outcome. The balance of complimenting the midrange frequencies allows the KOEL to handle acoustic tracks with ease and the genre that this particular set will gladly handle all day.

Jamiroquai came high and about with the KOEL’s higher frequency test with their Carla single in 16/44 FLAC and the KOEL/Jamiroquai collaboration created a less than crisp outcome. There is not much to grasp with the treble hits and was rendered soft and easy to the ears, this allowed for a loose and non-fatiguing experience. While there is great clarity and definition on the different instrumental notes and hits, a gamble on a tasty treble bite would have been welcome. Let me sneak in an inherent KOEL build discomfort as the rather elongated shell body created minor discomfort which balances out the would be longer listening session the KOEL’s highs would have permitted.

Soundstage and Imaging
Less than intimate, less than spacious, more on here and now. The KOEL’s soundstage is a good blend of intimacy and expansive, left to right and right to left panning is observable although not exceptional. Easy to deduce that the soundstage won’t be the reason you’d be picking up the KOEL. Imaging though was another story, there is great detail retrieval and instrumental presence is on a high, they can be easily placed here and there. Layering is a much more notable aspect on the KOEL than width and expansion.


The Brainwavz KOEL takes on an approach that is supposed to showcase a birds overall qualities and it indeed sang with its midrange performance and chirped its way with its complete accessory set. It isn't all bells and whistles though with the KOEL, a birds squeal was represented with its rather mediocre stock cable while the shrieks was represented by the minor build discomfort which when taking into account that ear shapes and sizes varies, is a matter of argument. The KOEL's midrange emphasized sound signature was done cleanly and while it once again suffers the usual BA-driven dilemma of a rather lack-luster low-end, it still creates an engaging and calming musical encounter. (At the $39.50 price as of 17/07/19, the KOEL is more than worthy of being checked out)
Pros: Good clarity, great mid range, good attack, good details, generous accessories
Cons: Bass weakness, can distort at high volume, thin timbre, average soundstage, so so construction.


SOUND: 7/10
DESIGN: 8/10
VALUE: 7/10

After having review the dual balanced B200 and quad B400, its time to give a try to the single balanced armature earphones from Brainwavz: the KOEL

The question is : can it cover whole frequencies range perfectly? The answer is : not exactly. While everything is there, there will be some compromise in sound, especially in bass region, making the Koel a mid centric earphones with plenty of richness to share.

Brainwavz use there famous 3D printer to make a particular housing, bigger than B200, and this is must likely to give a more ergonomic fit and perhaps expand the soundstage.

Now, let’s see in this review if a single armature can compete with other sub-100$ earphones without sounding too anemic.

Disclaimer : I wanna thank Brainwavz for sending me this review sample. As a no BS reviewer, i will keep objective my subjective hearing as well as a very important factor for me : price value.


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UNBOXING experience is always rewarding with Brainwavz and that even if I have to struggle to take off the cardboard around the fancy box. Once its done (this time I have to call the firefighter to help me take it off) we have a generous amount of accessories, especially for this price. One good quality cable, great quality portective case, foams tips and lot of silicone tips. Yep, Brainwavz really put lot of effort in product presentation and needed accesories. I admit that including 2 cables like with B200 or B400 will surely make them go bankrup for exagerated generosity so I can deal with that (anyway, I never use mic on cable, as I prefer getting brain cancer from my phone)

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CONSTRUCTION is well, hum, well, hum. To be honnest, i’m not sure about this plastic housing, perhaps the 3D printer they use isn’t up to date? Technology evolve so fast, I can imagine Brainwavz investing in super expensive 3D printer 2 years ago and nowadays we find better quality. Can’t say, but to me the look is rough, and quite DIY project style. Some part aren’t well polish and there a strange mix of opacity and transparence that puzzle me. As well, one of mmcx connector is a little loose in the housing, so quality check is to blame here. For the look did I personaly care? Nope : its in my ears and I don’t give a damn about what people think. But i’m worry about overall durability. Can’t lie (as other reviewers do so smoothly). Cable is of good standard quality and did not affect sound rendering negatively (proof that its a nice cable).

DESIGN is quite nice tough, wich is why in first place Brainwavz use 3D printer. Housing is ultra light and slip in my ears naturally. Still, its strangely bigger than what I expected due to B200 being very small, but I think Brainwavz take note of people saying the B200 have a too organic form that can be slippy and hard to take off the ears.



So, i’m the kind to listen to music the LOUD way, wich make me fall in an infernal circle of wanting to always listening louder. Lately, I change my habit and listen less loud, wich is still….too much for the Koel I think. This is important to take this aspect in consideration for my review.

Overall impressions aren’t negative at all, its just when distortion occur that i became very annoy and the very problem is either with too bassy music or too complex over crownded with instrument music. The brainwavz Koel is really impressive for a single balanced, it can cover about 100hz to 15khz I would say (that’s very must likely innacurate!). Mid range is where the magic happen, it have great detailed timbre while maintening a good transparency that permit above average imaging. Bass in another hand is perhaps punchy and still realist, but lack thickness and impact and feel thin, especially in sub where it can litteraly disappear. Treble is well extended and natural, little dry but quite snappy for a single balanced.

SOUNDSTAGE is average and have more deepnest than widness, I consider the presentation as intimate and in your head.

BASS is roll off and lack weight and impact, it sound rather thin and dry especially under 150hz. Mid bass save the whole game with an impressively fast presentation that have good punch due to extra timbre emphasis. The punch isn’t feel, its heard. But even if dry, this do not mean bass do not have any body to it, I just underline this because lot of people are basshead without knowing it, so, this is problematic for sure. Basshead run away : FAST!

MID range is quite delicious and will really impress people listening to folk signer or any type of signers that aren’t sit on big bass. It’s just enough bright to give a realist and detailed timbre. Tonality is right too and can transient response is fast. There good attack and decay. For vocal, female signer sound more natural than male signer due to lower end bass drop. Whole sound of Koel is slightly dry with good transparency, it help for overall agility of imaging. Vocal are intimate too, not super wide. I do not hear any important sibilance.

TREBLE is agile and deliver a quite detailed presentation. I feel its quite roll off around 10khz tough, but with extra micro details in upper range. Percussion sometime feel in background in a quite neutral way, wich is a plus in some sens, but there extra brilliance with high pitch metallic hit hat. Acoustic guitar lack grip and fine definition too. Inconsistancy of treble make the Koel very genre specific.

AMPING neew some power for those, and i find the Koel benifit from powerfull DAP or portable amp, it will expand soundstage and give more articulate imaging. However, bass can became more distort if ampin is too powerfull of not very clean.


SUB : 5.5/10

MID BASS : 7/10

MIDS : 8.5/10

TREBLE : 7.5/10

TIMBRE : 8/10


ATTACK : 8/10

KOEL VS E3000 :

Soundstage of is wider and more around your head than Koel more intimate and transparent one, wich have slightly more deepness to it even if it feel more in your head.

BASS of E3000 is more extended, thicker and more impactfull, it have better fuller timbre and more energy to it, but can slightly warm the lower mids. Koel have drastic bass roll off and feel thin and dry in this region, mid bass is more fowards but lack body wich make the impact quite light.

MID RANGE of E3000 is warmer and fuller, but more recessed than mid centric Koel. With Koel we have wide vocal presentation that feel more present than other frequencies range, while it is very appreciate for signers, it tend to stole the show of rest of instrumental and affect proper imaging. Mid range of E3000 is more linear and richer in the sens it show everything in 1khz-8khz range without discrimination and feel overall more balanced and natural than Koel. As well, male vocal of E3000 sound fuller due to better bass response.

TREBLE extend further with Koel, wich make them brighter too, but not in an unpleasant agressive way. Anyway, even if E3000 have rolled off upper treble, timbre sound richer and overall tonality more natural than dryier Koel, that while giving more micro details and sparkle, feel less well balanced and more distorted when lot of instrument mix up.

Construction of Koel is average, mmcx connection looking fragile as well as rough 3D printed housing. E3000 look more expensive than it cost, for Koel, its the opposite even if it have detachable cable.

Koel VS B200 :


SOUNDSTAGE of B200 is clearly superior in widht and dept and feel more spacious and airy than the more ‘’in your head’’ and intimate spaciality of B200.

BASS of both this earphones isn’t very impressive, both being rolled off and quite dry, still B200 have more punch and better separation than Koel.

MID range is similar again, both of this iem being quite mid centric wich make them feel balanced, the B200 have little more body and widness, making the vocal floating instead of being stock in middle of instrumental like the Koel.

TREBLE is similar as well, giving detailed but dry texture to timbre and having distortion problem time to time at too high volume. Due to better imaging of B200, there more decay and sparkle to highs, while the Koel are crisp and fowards.

Both construction use same plastic, but B200 is smaller and will fit more easily any ears.

VS BQEYZ BQ3 (55$):

SOUNDSTAGE of KOEL is airier and about same wide of BQ3, but less holographic, deep and tall.

BASS of BQ3 is more extended, have more weight and resolution and better attack than drier and thinner sounding Koel.

MIDS of BQ3 have more body but are less texutured and presence than more mid centric Koel, wich have wider vocal presentation as well as brighter more detailed mid range.

TREBLE of Koel is brighter but less extended than BQ3, but it feel more balanced and linear, and while BQ3 have more brilliance in upper range, Koel have more sparkle in mid treble. Anyway, layering of BQ3 is from another league and level of microdetails is better too.

CONSTRUCTION of Koel look fragile and kinda ugly, while the BQ3 look sturdy and beautifull. Koel is less comfortable and can have problem to fit properly due to strange housing shape.



For a single armature iem, I can’t say the Koel are bad at all.

These are very detailed and cohesive sounding earphones with marvelously rich midrange.

Still, I would suggest to buy the B200 over these for a more immersive sound experience with bigger soundstage and more extended dynamic in both end.

As well, the construction and quality check is a little problematic for earphones in this price range if it was 20$ I would not even talk about it, but at 70$ we need to be more severe.

All in all, if we only take sound aspect, the Koel are very capable earphones and quite impressive if we give credit to single balanced armature aspect, it sure isn’t an all arounder, but have a particular finess and agility that will benifit instrumental music and all type of acoustic instruments. If you listen at high volume or are an addict to bass performance, the Koel isn’t for you, but if you want to hear your favorite (female) signer in an rich intimate space, the Koel will sure impress you.
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