Signature Acoustics O16 Live


Headphoneus Supremus
Pros: soundstage, value, resolution, build quality
Cons: isolation, lows could be more arid, slight mid veil

Before Faheem contacted me on Head-Fi and introduced me to the company and asked if I was interested in checking out their recent and upcoming products, I never heard of the Indian audio company “Signature Acoustics”.

In 2011, a group of enthusiasts and reviewers of the Indian hi-fi distributor Pristine Note decided to found their own headphone company, Signature Acoustics ( They sell their in-ears in India, but also world-wide.
Faheem then kindly arranged the shipment of their three models, the current C-12, O-16 and the upcoming Be-09 for my honest evaluation. I have then merged the three reviews into one for a better overview.

Technical Specifications:

C-12 Wooden:
MSRP: ~$40
Driver: 8 mm (CCAW)
Impedance: 18 Ohms @ 1 kHz
Frequency: 17 to 20 kHz        
Sensitivity: 102 dB
Total length: 1.2 m (split length 28 cm)
Channel Balance: < 2.5% dB @ 1 kHz

O-16 Metal:
MSRP: ~$55
Type: Open back
Driver: 8 mm (CCAW)
Impedance: 17 Ohms @ 1 kHz
Frequency: 12 to 22 kHz         
Sensitivity: 102 dB
Total length: 1.2 m (split length 28 cm)
Channel Balance: < 2.5% dB @ 1 kHz
Connector: 3.5mm Gold Plated Stereo Pin

MSRP: ~$30
Type: Earphone with Mic (Headset) with Nokia/Apple configuration
Cable Adaptor 3.5mm Male to 3.5mm Female TRRS adapter.
Adapter Pinout: T-T, R1-R1, R2-S, S-R2. Ground and Mic are reversed, so it may be used for compatibility between Apple and Nokia type earphones.
Length: 1.2 m
Driver: 10 mm CCAW
Impedance: 17.5 Ohms
3.5 mm TRRS Gold plated pin

Delivery Content:

C-12 Wooden:
See Be-09 (the test sample arrived only in a clear plastic bag with the medium silicone tips).

O-16 Metal:
See Be-09 (the test sample arrived only in a clear plastic bag with the medium silicone tips).

The Be-09 arrives in a black packaging which has got two plastic screen windows on the front that allow you to take a look at the in-ears and the carrying case.
The back side contains a large company logo and a description of the company’s philosophy.

Opening the package, the in-ears and the delivery content, which consists of a cable clip, a real leather carrying case with the company logo, three pairs of silicone tips and a quick start guide get revealed.

IMG_0607.jpg IMG_0608.jpg


Looks, Feels, Build Quality:

C-12 Wooden:
The in-ears are made of really well manufactured real wood and have got an “SA” logo on their faceplate. The cable is twisted and then coated by a layer of plastic. The 3.5 mm plug is L-shaped, but a bit angled as well. Except for at the connector, there is almost no or only very stiff strain relief and no chin-slider.
The build quality of the in-ear bodies seems very good and valuable, but the cable could be more flexible and less springy.
The side markers (L/R) are only barely visible.



O-16 Metal:
Just as the name says, the in-ear bodies are made of metal and have got a good build quality. The faceplate features a silver metal mesh which is surrounded by an orange metal ring which contains the Signature Acoustics lettering as well as the side markers.
The cable is the same as the one that is used for the C-12, though the coating seems to be a bit thinner, hence the cable is more flexible.


The new Be-09’s bodies are made of halfway shiny red and halfway black metal and appear to be well made as well, with large side markers on the bottom. The y-split is made of shiny red metal too and features a white Signature Acoustics logo, but also lacks a chin-slider. The straight 3.5 mm plug is made of black metal.
The cable is also twisted and then coated on this model and has no strain relief at the y-split, but a good one on the other cable transitions. The left side features a one-button remote control with built-in microphone.

IMG_0611.jpg IMG_0612.jpg


Comfort, Isolation:

All three in-ears have got the same good wearing comfort but strong microphonics as well when they are worn with the cables straight down. However, microphonics can be reduced by a strong amount by guiding the cables over the ears, which works very well as the in-ears are fairly small. This drastically reduces microphonics, but they could be even completely eliminated if there was a chin-slider.

C-12 Wooden:
Isolation is fairly high, as there is only a tiny vent in the in-ears’ bodies.

O-16 Metal:
As the O-16’s back side is completely open and only covered by a silver metal mesh, isolation is only barely present as a consequence of it.

Quite similar to the C-12, Be-09’s isolation is fairly high, but probably just a tad lower than on the wooden in-ears.


The in-ears were burnt in (just in case) before I started listening and testing. Source devices were mainly the LH Labs Geek Out IEM 100 on the computer as well as the iBasso DX80 and Shanling M2.


C-12 Wooden:
The C-12 has got a bass-bloated, consumer oriented sounding with thick upper bass and a ground-tone that clearly bleeds into the mids. The massive emphasis of about 15 dB overshadows the mids when bass-heavy tracks are being played back.
Midbass, upper bass as well as the lower ground-tone are about on the same level. From midbass on, level starts decreasing evenly and just stops in the area of the mids. Sub-bass is somewhat rolled off, but still audibly present.
Mids are warm, thick, mellow and voluminous.
Treble is (except for some sparkle in the upper highs) in the background and makes the sound appear warm, coated and mellow along with the mighty ground-tone.

O-16 Metal:
I’d consider the sound as being warm and bass-oriented.
Bass alongside with the ground-tone is emphasised by about 10 dB compared to a flat IEM and gives the O-16 a warm and smooth character. The emphasis goes evenly from the sub- over the mid- and upper bass and starts evenly rolling off from the upper lower ground-tone on, into the upper ground-tone, where it still bleeds in a bit.
Mids are present and more on the warmer side; voices however sound quite good, without too much warmth, although a certain amount of warmness and sweetness can’t be denied.
Presence area is recessed and guarantees for strenuousness-free listening. There is a small peak at 5.6 kHz in my ears, else the treble is soft and in the background.

Three words entirely describe the sound of the Be-09: “starkly v-shaped signature”.
Down from the upper middle ground-tone, level starts increasing the whole time down to the mid- and sub-bass where an immensely strong emphasis of about 16 dB can be heard. The upper bass is also strongly emphasised, but a bit less.
Mids are obviously in the background and rather on the bright side, but tonally quite well made – but even obviously in the background.
The following presence area is in the background; the treble features an even, but strong emphasis from 5.5 to 7.5 kHz, which sounds metallic, but not piercing because it is rather broad-banded.


C-12 Wooden:
For better evaluation of the resolution, I reduced the strongly emphasised areas with an equalizer.
The resolution of the C-12 is only modest, with veiled and coated mids and blunt, slow, unprecise lows, which is especially audible with fast music and tracks that have got a higher amount of bass (not to be mistaken with bass-emphasised music).

O-16 Metal:
Here, the resolution is on a really good level. Mids as well as treble are high resolving, with a good amount of details and precisely differentiated instruments, although voices are minimally veiled.
Bass is (comparatively) fast, although rather on the soft side. Fast double- and triple-bass punches are still recognisable as such, although I wouldn’t mind more aridness.

Overall, the Be-09 is higher resolving than the C-12, but doesn’t reach the amount of details the O-16 has.
Treble is similarly resolving to the O-16’s, but mids don’t have as much details and sound “flat”. Although lows aren’t spongy, they are definitely on the softer side and fast bass-punches sound muddy.
All in all, I see the Be-09 a bit closer to the O-16 than to the C-12.


C-12 Wooden:
The soundstage is averagely wide, but doesn’t really have a distinct or precise instrument separation. There is some spatial depth, but single layers are hard to detect.

O-16 Metal:
The soundstage extends very wide and deep and is very spacious. Its dimensions remind me of soundstage monsters like the Brainwavz R1, Sennheiser IE 80 or KZ ZN1.
Instrument separation could be a bit better and so there is not too much space between single instruments, but that is really nothing to blame the IEMs for at this price.

The soundstage is wider than the C-12’s and has also got more depth (but it is not as large as the O-16’s by any means). Instrument separation is surprisingly precise and about on the same level as the O-16.
Overall, I’d consider the soundstage as being well made.

Not including personal preferences but only focussing on the technical strengths, I don’t find the C-12 Wooden that good. It is okay with slow recordings and doesn’t sound too strained with those, but loses control and sounds muddy as well as unprecise with fast music and tracks that have got more low-end. Overall resolution is unfortunately blunt as well, but there are at least no annoying peaks or valleys.
Except for the cable without strain relief, build quality is excellent and the included carrying case is good as well.
All in all, I come to a rating of 45% or barely rounded 2.5 out of 5 stars.

The O-16 is definitely the strongest IEM out of the Signature Acoustics line-up. The sound is warm and bassy, but quite controlled and resolution is quite high as well, although the lows could be more arid. The in-ears only barely isolate ambient noise which could be a problem for some.
The soundstage these in-ears generate is very spacious and outstanding.
The build quality is quite excellent. The accessories (carrying care) are good.
Overall, I give the O-16 77.5% or rounded 4 out of 5 stars.
The Be-09, Signature Acoustcs’ latest model, has got a classical “fun” sound signature with an immensely strong v-shape and typically pushed back mids.
Resolution is more or less decent, but doesn’t reach the level of the O-16. Soundstage is good as well, though not as large and precise as Signature Acoustics’ other metallic in-ears.
Build quality is very good and the handmade leather case is a nice addition.
Overall, I come to a concluding rating of 65% or rounded 3.5 out of 5 stars.


Headphoneus Supremus
Pros: fairly balanced, solid overall performance for the price
Cons: almost nonexistent isolation, sound leakage, some dryness
First off, I want to thank Faheem and Singnature Acoustics for this O-16 Live unit and apologize for the humongous delay (it’s been very long) of this review.
Packaging and Accessories
The package is relatively simplistic. On the front here are two plastic windows showcasing the SA leather case and the O-16’s housings.
On the back of the box there is a short description of the Elements series.
Inside the box reside the O-16 and the genuine leather case. There are also the included shirt, some extra filters and the included tips. There are 3 different types of single flange tips.
Also inside is a pamphlet/warranty card
Build Quality, Design and Fit
The O-16 has metal housings, which feel solid and durable. The cable looks and feels sturdy but is on the stiff side and is memory-prone, although I have to admit that it feels a touch softer and less prone to kinks than the cable of Signature Acoustics’ C12 even though supposedly they are the same.
Design-wise the O-16 seems fairly standard until you look at the back of the housings and see the metal mesh. The O-16 is an actual open-back design unlike some iems, which only appear to be such but the meshes on the back are purely cosmetic.
The fit is good but that’s also the first time one comes face to face with the open-back design drawbacks of O-16. As there is pretty much no isolation that makes it hard to determine if you’ve achieved a good fit or not as surprisingly despite the open back tips should still make a good seal at the nozzle which is a hard thing to do and can take some fiddling and trial and error.
 The O-16 is meant to be worn straight down but could be used in an over-the-ear just as easy due to the short strain reliefs. There is no driver flex, which is no surprise given the low isolation. The same goes for microphonics – nonexistent due to the open-back design.
The O-16 Live has over 100 hours of burn-in at the time of writing this review. O-16 is the second iem from Signature Acoustics' Elements Series and apparently is supposed to represent "air".
The bass is not too pronounced and is relatively tight but lacking a bit in depth and impact most likely due to the low isolation. It’s still decent but a touch on the soft side and slightly lacking in thickness and body. On the positive side, it doesn't bleed into the mids and has good speed.
The mids are fairly neutral and balanced with the rest of the spectrum. The note presentation is a touch thin. The overall tonality is slightly on the warm side. Vocals have good presence but there is a hint of dryness in them. Clarity is pretty good due to the thinner note presentation and good separation. The mids are natural with some sweetness to them but O-16 seems to struggle a bit with the layering. Overall there is just certain naturalness to the sound and its timbre. I also experimented with blocking the vent and that natural sound is lost and vocals start sounding nasal.
The highs are well extended. O-16 is not prone to pointing out sibilance but can sound a bit shouty at higher volume. There is a good amount of shimmer and sparkle. Overall the treble has good presence without imposing but is slightly smoothed over.
O-16 sounds airy. It has good center imaging and overall positioning. Width and depth are pretty good but even though O-16 has pretty good imagining it’s not really throwing sound cues as far as other iems despite its open-back design. But still while the overall soundstage might not be the biggest, O-16 is fairly open and with good separation.
The O-16 Live is only the second iem from the Indian company Signature Acoustics but it’s showcasing their improvement since their first product the C12 and that they know their stuff.
On the other hand, there is the huge drawback in the design, which cannot be just brushed aside – the open back. Signature Acoustics acknowledges and accepts that it creates limitations in the use and also in the number of potential buyers. As can be seen even on the pamphlet included with O-16 they admit that the isolation suffers and that they think O-16 should be used in quiet listening environments, which kinda defeats the general purpose of iems. But some people like to be more aware of their surroundings and if they can get past the fact that there will be also sound leaking to the outside and people might judge their musical preferences, then the O-16 might be exactly what they are after.
In the end O-16 Live is a solid performer overall, especially for its price, which at the moment is around $30. It has its pros and cons and it’s up to the potential customers to weigh them in and decide. I for one had a smile on my face when I first heard it and I think it’s quite competent and enjoyable. 


IEM Reviewer Extraordinaire
Pros: Well-rounded Sound. Good Soundstage. Price.
Cons: Poor Isolation. Slight stiff cable.
It might be a bit odd to name an IEM the O-16, as in ‘oxygen’. But given their first IEM is the carbon (C-12), I guess the India based Signature Acoustics does meant to create a real ‘Element’ series based on the periodic table. As their second product, the O-16 continues to target the budget IEM market and one can be found for just US$30 or so.


Driver: 8 mm (CCAW) Open Back Dynamic
Impedance: 17 Ohms @ 1Khz
Frequency Response: 12 to 22 Khz
Sensitivity: 102 dB
Total length: 1.2 m
Channel Balance: Less than 2.5% dB @ 1 Khz
Connector: 3.5mm Gold Plated Stereo

Packaging, Accessories and Build Quality
The new IEM comes in the case paper box as its elder sibling, so there really isn’t much to say about. Accessories wise, it is the same story – there are three pair of eartips, shirt clip, two pair of replacement filters and the really good looking leather case. Build quality is decent as well, nothing to complain about. The two tone color scheme is quite shape, in a good way no less. The only thing to mention is the cable - while good quality, it is a bit on the stiff side with minor memory effect. Same as the one found on C-12.
Last but not least: since this is an open back IEM, isolation is, as expected, not great. So it is not going to be a good choice on noisy places, but more for in-da-house kind of situation.

Sound Quality
The sound signature of O-16 is warm and sweet with a slight emphasis on the midrange. Good extension on both ends, but does get a bit rounded off. Bass has good quality and decent quantity, polite in a way but not shy by any mean, though not stand out on their own either. Same can be said to the treble – clean, clear, polite and not exactly bright or exciting. There are some sparkle and micro-detail, but often they don’t stand out enough. Mid is just slightly sweet, well textured with a good thickness to accentuate the vocal. It is further helped by a good soundstage that is aided by the open back design to give it a musical and fluid presentation.
All and all, the O-16 has a well-rounded sound – mature, polite, not boring by any mean but also lacks just a touch of excitement that could have excelled it to the next level. It could very well being said to be a gentleman’s IEM – a rather safe choice, so to speak. It has the same easy-goingness of its elder sibling, the C-12, but a little conservative in tuning. If C-12 is that one you want to listen outdoor, then O-16 is definitely the one that you want to listen indoor, in a nice quiet place with some smooth music. The safer tuning does however make O-16 more adaptive than C-12 when it comes to different genres of music.

Overall, O-16 maintains about the same level of performance of C-12, but tuned in quite a different way with their own pros and cons. The openness of its presentation does in fact gives O-16 kind of a ‘live’ feeling, though it is more of a small venue with Jazz music rather than a big stadium with Rock music. For the price of US$30 however, it won’t be fair to ask for perfection anyway. All being said, the O-16 is still well ahead of most of its competition in the same price bucket. Once again, Signature Acoustics might be a new comer in the IEM world, they certain know their game.
A thanks to Signature Acoustics for the sample
Don't known any American reseller, but it can be found on eBay India, listed by Signature Acoustics main dealer and they do ship worldwide. With shipping to US included, it comes out just under US$50.
I ain't gonna lie....i looked at that leather case like 10 times. That is included with a under $50 set of IEM ? If that's real leather that's cool as hell.
It is indeed real leather.
Pros: Ever so grown up. Polite. Wonderful soundscape.
Cons: Cable memory. Meh isolation. Not particularly exciting.
Signature Acoustics O-16 Quick Review
Full review found here
Thanks to Signature Acoustics for the sample.
Brief:  A pleasantly lovely IEM from India
Price:  4000 Rupee’s or about £42 or about US$64
Specification:  MODEL: Elements O-16 Live, Type: Open back, Driver: 8 mm (CCAW), Impedance: 17 Ohms @ 1Khz, Frequency: 12 to 22 Khz, Sensitivity: 102 dB, Total length: 1.2 mts (split length 28 cms), Channel Balance:  < 2.5% dB @ 1 Khz, Connector:  3.5mm Gold Plated Stereo Pin
Accessories:  Silicon Ear Tips (S,M,L), Earphone Filters, Shirt Clip, Leather Case
Build Quality:  Seems allrighty.  Buds are rather light but look nicely finished.  The cable feels sturdy but has quite a bit of cable memory.
Isolation:  Rather so so.  It’s got a big back vent that’s rather big and so these really are not big isolators at all.  Better than buds, sure but low by IEM standards.  Not one for flights or horrible commutes unless you like to be able to keep an ear out for things.  With music playing, you might hear that bus coming up behind you but maybe you won’t.  Eyes people!
Comfort/Fit:  Pretty nice.  I could wear them up or down effortlessly and was a simple shove in and done.  Which is how I like it to be.
Aesthetics:  Hmm I find the dark greyish offset with a bright coppery metallic right quite nice.  A little hint of flair but nothing too ostentatious.
Sound:  Nice.  Nice and pleasant are the key words for the O-16.  They are a highly unassuming and polite IEM.  They have no V shaped drama going on at all. They are actually a hint middy, their lows and highs are both the height of polite reticence.  I found they really were at their best on soothing tune’s, Bach’s choral works were eminently lovely.  Something I could happily slap on and let just melt away.  In fact any music of this nature I found made for a lovely pairing.  If you make them get a little bit more poppy and aggressive it will do as you ask but it still kept a faint air of politeness.  It was highly credible but then Diana Ross appears on them and they felt like they had come home.  The treble is missing a bit off the top and if forced to become abundant can get a little bit hard edged.  The bass if pushed becomes rather expansive but again its extension misses out a little.  Mids are pretty good, wide and air filled presentation.  Actually its sound staging is one of it best features, being so open they sound super open too and so very wide.  It’s really all quite lovely.
Value:  It price puts it head to head with the GR06.  The O-16 has such a grown up lovely sound but the 6 is the more versatile beast.  Much like its aural qualities, the O-16 is nicely pleasant value.
Pro’s:   Ever so grown up.  Polite.  Wonderful soundscape.
Con’s:  Cable memory. Meh isolation.  Not particularly exciting.

just to make it known, the chaps at Signature Acoustics have let me know they are currently on an introductory offer.
that means the current price is just 2000 Rupees, with free shipping within India and international (worldwide) shipping is an extra 1000 making them in total just 3000.
so that makes them about £31 or US$48 internationally (at todays exchange rate anyway)  thats a pretty hefty price cut while it lasts especially if youre in India, at that price its pretty much got to be the value king.


500+ Head-Fier
Pros: Wide Soundstage, Extremely linear midrange, Smooth treble, Ultra low microphonics, Uncoloured, Very good value.
Cons: Occasional stretching in the vocals, Cable memory, Could do with more detail overall.
 Signature Acoustics O-16 Live Review : 
Setting the Stage 

INDEX (Click to jump directly to sections):
  • Introduction​
  • Packaging, Accessories and Comfort​
  • Sound​
  • Common sound impressions​
  • Let’s do something about it/Mods​
  • Comparisons​
  • Value and Conclusion​

The O16 Live is India based Signature Acoustics' second entry into the IEM world. Their debut IEM, the C-12 Elements, received favorable reviews all around (including ljokerl and ClieOS). I'd like to thank Signature Acoustics for giving me the opportunity to give the O16 live, a full unbiased review.
Sources, music and other misc details relevant to this review can be found in the second post
Packaging, Accessories and Comfort :
  1. Right from the high quality cardboard box  to the smell of the quality leather pouch that hits you, the O16 package is a pleasure to unwrap. The barrel shaped IEM is crafted out of metal with a gold-orange ring at the back that holds the largest mesh I have seen in an open back IEM. The strain relief sports a wide base that seems to be steadied within the housing.
  2. The cable is the second most interesting feature (after that gigantic mesh). It features tightly twisted cables covered by a shrink wrapped sheath. This design does result in rather alarming shape memory, but almost completely nullifies microphonics (even when worn cable down). The cable sports a minimalistic Y split and is terminated in a nearly 90 3.5mm jack.
  3. The tip selection is pretty basic with 3 sets of wide bore and one M set narrow bore (pre-installed). a shirt clip, replacement filters and a leather pouch rounds off the accessory list.
  4. The earpieces are light, the nozzles are sufficiently long and can be worn for hours at length without discomfort.
Sound :
The O16 is a specialist IEM designed to play well with live recordings and vocals. The sound signature delivered by that 8mm driver is only one part of the mix. The open back design aims to complement the sound signature with a spacious soundstage, which should bring those live recordings to life. Let’s see how it got on during my listening tests.
  1. Overall: the easily driven O16 exhibits a warm neutral if not mid forward signature. Perceived frequency response is not aggressive or peaky. Low end extension is good at normal listening volumes. I noticed a rise from the bass resulting in a mid-bass hump centred around 120Hz. The midrange is linear (except for a slight dip at ~2.4k) and continues into a well behaved treble range. There are a few well controlled peaks at 4.8K, 7.6K and 12K that are way within reason and keep things lively enough. The open back design means it would not isolate well at all, but it was never meant to. And therefore, is not a negative trait.
My initial plan was to do an album-wise write-up of my listening impressions. Instead, I will briefly describe the conventional split and round it off in the common sound impressions section.
  1. Bass: The bass is plenty sufficient for live recordings and does not seem lacking on other music types. It is far from bass head levels as it should be. It manages to stay completely clear from the mids, except for imparting warmth to the vocals. This keeps things natural and as a result is more involving. Cons: The midbass is not very detailed and often loses some finesse. The sub bass while having presence does lacks attack. I talk about this more in the common sound impressions.
  1. Mids: Midrange is extremely linear and is quite accurate. Both male and female vocals are equally intelligible. The accuracy, linearity, slightly forward and uncoloured nature of the midrange results in a very involving experience, one that is critical for live recordings(but see cons). Analytical listeners might pine for more detail. Cons: On a few tracks, midrange smearing/stretching is evident. Average depth. Extremely dependant on the recording and mastering. (Elaborated in the common impressions section)
  1. Highs: Very very polite and smooth. Transition from the mid-range is very smooth. If it wasn’t for the controlled peaks at 4.8K, 7.6K and 12K, it would have seemed a little dull. As a result, it manages to bring instruments to life. Detail retrieval is good but not the best.. Cons: Treble may be too smooth for some. Analytical listeners may require more detail. More in the common sound section.
Common sound impressions:
So how does it all coalesce together into a music experience? Thus far, I’ve steered clear of its party piece, which is the open back design. Evidently, the aim is to supply that much needed air that live recording mandates.
While the design does benefit the sound in some obvious ways, it does have its side effects. We’ve established that the sound signature is natural, non-intrusive and smooth. This is mostly down to the driver tuning. The separation, imaging, soundstage, intimacy, I feel, are mainly properties of the housing, damping and internal design. Please not that what I describe next does not apply universally, but is extremely recording/track dependant (some more than the other. Some tracks are unaffected).
The soundstage is wide no doubt but it seems to come at a price. The aforementioned cons I feel are due to the extreme open back design. The driver is moving enough air but is unable to generate sufficient pressure to result in a fast impact, before it decays away. Some detail in the bass is lost here and the edges of the bass may seem woolly on some tracks as a result. They absolutely do not interfere in the mids, which would have been an instant downer otherwise.
The mids also exhibit some quirks which I am pretty sure is due to venting and resonance caused by the design. This is slightly difficult to explain, so please bear with me.
Before I talk about the mids I must, at last, discuss the soundstage. The width is impressive, and is always a little wider than normal.
A wide soundstage, in my mind, is where the instruments and singers are clearly distinguishable and are spread in the sonic space as the track demands. As the soundstage widens the separation increases but the dynamic range, integrity and tightness of the individual components are retained. This is where the O16 takes a slightly different route. It’s analogy time! Please forgive me, but the following is the best way I can convey what I was hearing. Imagine a picture printed on a balloon. Deflated, the picture makes no sense. Inflated halfway you can understand the picture and discern individual components. Three quarters inflated, the picture looks perfectly proportioned and the individual characters in the picture are naturally spaced. As the balloon keeps inflating, what you wish for is the individual characters to maintain their proportion but for the space between them to increase. Instead, even though the overall image is now getting bigger, the individual characters are being stretched and starts to lose its natural feel. This is exactly what happens on certain tracks with the O16, the vocals (and certain instruments) seem to be stretched over the wider than normal soundstage. The treble range is relatively unaffected by the soundstage.
A very important point to note is that this is recording specific. Just like how every picture has to be spaced differently to seem natural, each recording carries with it special cues that need to fit within soundstage and not extend beyond. On many of the recordings, the O16 is brilliant at portraying a very natural and wide space that is easy to lose oneself in.
Soundstage depth is a very complex phenomenon (that I don’t quite have a grasp on) and is an amalgam of driver tuning, efficiency, housing, damping and who knows what else. The O16 isn’t impressive when it comes to depth perception. It feels just average, and is dwarfed by the width.
Let’s do something about it/Mods:
I found myself thoroughly enjoying many tracks and instinctively skipping some tracks within the first minute. Identifying a pattern in the nature of the tracks, I deduced that it was related to the open back design and not the tuning. I melted symmetric holes of different sizes into thick double sided tape, and stuck them over the back mesh. Larger sizes seemed to have no effect. A range of smaller sizes worked a lot better.
Results: Much to my delight, vocals and bass have now gained control on the troublesome tracks. The soundstage is smaller but are definitely not below average. While a particular size played well on most of my albums, I found that certain sizes brought about the best in different albums.
I thought about it for a while and sketched a mechanical step Iris that can be easily adjusted to different positions. My drawing was shabby, so I found this gif which basically shows what I intended. This way the soundstage width, airiness can be controlled to your taste. And now, it could also be used outside/noisy environments with the iris fully shut. I do not know if there is any other IEM that does this. But, it could be a first and a very nice feature to be able to control intimacy in your music while retaining a smooth warm signature.
he Vsonic is more impactful and heavier through the lower range. Recession in the mids is more apparent next to the O16. The rise through the upper treble and sibilant peaks are absent in the O16. The O16 is more accurate while the VSD1S is more fun. The VSD1S also has a good sense of space which doesn’t feel lacking next to the O16, just narrower.
HiFiMAN RE400:
The more expensive RE400 is like a brother from another mother. 
They share a similar warm slightly mid forward signature. 
The bass on the RE400 is faster and carries more detail. The O16 boasts better sub-bass presence but isn’t fast and impactful.
Both are fairly accurate in the mids, but the RE400 pulls ahead in sheer quality, clarity and texture. Both are very smooth through the treble. The RE400 is crisper at times with more micro detail. The RE400 sounds congested next to the O16 but is slightly ahead in terms of layering and depth. Overall the RE400 has more finesse/control and clarity.
Value and conclusion:
I can drone on about the specifics of the sound. What matters is how much bang does it deliver for your buck. The O16 currently retails at a very impressive 65$. For the money, it delivers what it advertises and then some. This sort of uncoloured sound isn’t easily found at this price point. And coupled with the spacious stage it makes for a very sweet deal indeed.
If you are looking to enjoy and lose yourself in live/vocal recordings on a budget (without getting too analytical), the warm smooth O16 live with its open back design is a no-brainer. (Just bear in mind that not all your music will necessarily shine.)
Did I mention the Early bird price of 30$? Well. yeah

Thanks for reading. Let me know if you have any questions. And I'd love to hear your suggestions.
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