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A Very Complete Review of the T2

(Note : The current T2 is that referred to at the T2PRO ,the T2i has since been discontinued)


The protagonists of this review are Advanced Communication Solutions ACS T2PRO and Advanced Communication Solutions ACS T2i in-ear-monitors. Both of them utilize the same highest fidelity of sound reproduction from an IEM, with T2PRO being directed at the professional market and T2i finding its place at the consumer audio aficionados.

How To Set Out

- Ordering Possibilities

Both of these high-end in-ear-monitors can be purchased solely from ACS Advanced Communication Solutions, the price for each IEM being £499. It is also possible to find your way through one of ACS' 300 outlets scattered throughout the U.K.'s territory (available outlets are listed on ACS' website). Unlike some other suppliers, who charge for ear impressions separately, the cost of ear impressions taken by ACS is already included in the price tag. As I am writing this review the ACS' website is still under construction.

- Ear Impressions and Fitting

As every custom-made in-ear-monitor T2PRO and T2i require taking one's ear impressions. It is possible to have them taken at a local audiologist's office and later on send these to ACS' H.Q. However, in order for the ear impressions to be perfect one needs to find a competent, professional audiologist who has the required knowledge not only of taking ear impressions for making hearing aids, but the one fully trained and accustomed with the idea of working with IEM's. There is also a possibility of taking ear impressions yourself (various D-I-Y Kits), but it will certainly be harder, if not impossible, to get satisfactory final results. The best option is to pay a visit straight to ACS H.Q., where professional and kind-hearted specialists will take care of you. It is a guarantee of a perfect fit, which is crucial and elemental in a properly functioning, finished product. Personally, I have chosen the third option and I highly recommend this one.

General Assembly

- Specifications

~ Driver housing

Driver housing is custom-molded and double-bored with special soft silicone full shell.

~ Frequency Response: 20-16,000 Hz (sole numbers are meaningless anyway!)
~ Impedance: 27 ohms nominal
~ Sensitivity: 109dB for 1 mW
~ Weight: 1 ounce

- Accessories

The contents of the package include: monitors, a waterproof "pelican" case, a smaller, nice, black leather case with “ACS” and their site address engraved on it, a double-tipped wax pick, 1/8" to 1/4" adaptor and instruction manual (shirt clip and some cream are optional, I believe).

- New Specification Drivers

As most of the high-end IEMs, T2PRO and T2i use the two balanced-armature drivers, responsible for high and low sound spectrum, both of which combined, deliver astonishing mid-range (utilizing twin transducer technology) via passive crossover. Wonderfully tuned drivers is what differentiates them from other products, being an upgrade of their earlier products (T2XS) which used the identical components as the U.S. Sensaphonic ProPhonic 2X Soft.

- Enhanced Durability

ACS's monitors are precautionary equipped with augmented hallmarks allowing greater durability of the inner parts of the products.

- Cable Differentiations

T2PRO's cables come in a teflon-braided version or a break-away one.

The regular teflon-braided cable is available in 50". The very cable is entirely enwrapped in special kind of silicone, it is teflon-braided from the gold-plated, “L” style bent plug (3.5mm) with a transparent casing, up to the small joint from which two, very thin, but sturdy, red and blue wires spring out (also enwrapped in silicone).

The wires are not detachable from the driver housings and enter the innards being preceded by self-adjusting “memory wires”. The wires up the joint are very stealth.

The second option is T2PRO with a teflon break-away cable (custom lenghts are available). The break-away cord terminates with a female-plug adaptor at the joint of the left and right cables.

T2i is a brand new alternative and the cable is longer, very soft, doesn't have "memory wires" and it gives you another option of wearing the IEM's like T2PRO (over the ear) or just with the wires hanging down one's ears. I guess it is made of nylon and the default colour of the cable is white (it's a commercial version), but is also available in other colors (mine is black) and transparent.

As far as I know (not having the break-away version), all available options are microphonics-free, which means that there is no conduction effect.

- The Looks

T2PRO, being professional, are available in a transparent version. They are not crystal clear, but more translucent; enough, however, to melt with one's skin color which provides more stealth overall looks.

T2i are available in a more varied range of colors: white, black, red, blue and pink.

To differentiate between the right and left monitors, T2PRO are color-coded with a red and blue dot on each respective monitor. T2i have a red dot on the right hand side.

Both are magnificently and meticulously crafted.

Sound Quality

- Reality of Sound Reproduction

T2PRO and T2i do not have any preset capabilities of reproducing the sound, but act accordingly with the recording and its every, tiniest nuances. The music flows through one's mind without any traits of expressing some conspicuous characteristics imposed by the manufacturer. It is just music as it is and it fluctuates. As far as I know, every musical device, being that a headphone, an in-ear-monitor, a speaker, etc. are equipped with a degree of coloration. This effect is non-existent here (or at least I have not experienced any).

~ bona fide decay (vocal and acoustic reproduction)

As it happens, most of the vocals naturally take place in the mid-range and they are truly immaculate. It is hard to imagine such a pure presentation and palpable reality. When I received the IEM's for the first time I was under impression that if you got the right source and recorded some real sounds, obviously listening to them in real time, it would sound even more “real” when listening through the monitors later on than the actual reality. The perfect isolation makes up for it even more. It was almost a blood-curdling experience when listening to the first track from the binaurally recorded Stax Set-Up CD with those people actually whispering into MY ears, not a dummy head one's, or the moment when the window is being open- I could actually feel the cool, fresh air caressing my face; a moment of epiphany, you might call it (and, no, I do not know whether the air outside was cool in the actual recording). Anyone who claims that you cannot achieve a soundstage in an IEM should listen to such samples. If only more music was recorded binaurally. Similarly, one should take a listen to some remastered Nick Drake's albums e.g. and, in a truly synesthetic approach, actually touch the strings of the guitar with, not yours, but his fingers; or Albinoni's Adagio in G Minor for that matter, and you have the musicians right there playing solely for you. Decay of the particular notes is startlingly real, but, at the same time, lacking excessive overhangings. The overall twang of the electric guitar in other recordings is also mastered quite well.

- Treble

Treble is accurate, natural and clean, with precise highest notes, beautifully delineated. Razor-sharp and accurate signal extends very high without a single hint of sibilance present. One can pinpoint separate notes which show off their liquid and biotic-like characteristics as the attack fires off and naturally decays to start another. Clarity and crisp detail as shown through a magnifying glass.

- Midrange

Midrange is soft, buoyant, warm and liquid-like. The passive crossover very efficiently utilizes the tuning technique and amalgamation of treble with bass inside the ear canal. The IEM's do not suffer from compressed soundstage in this part of the spectrum. Midrange is very precise, transparent and textured as it mingles with respective higher or lower notes according to the recording. It is very linear and focuses neither on the frontal nor on a more distant, rear-like presentation. It is like Aldous Huxley's “Marriage of Heaven & Hell”.

- Bass

Bass is in no way linear and one-note, boomy collection of loose lower-end sounds. It is affluent, vivid, layered and exhibits rounded, dimensional and spherical traits. Higher, mid and lower bass notes are all there doing their fine job and they are thumping just where they are supposed to be. Controlled and tight, the signal can descend abysmally deep, so that it is no longer heard but is felt, being fired through the Thalamus and letting the sweet transduction of electrical vibrations begin, reaching the innermost strata of one's brain with skull-wobbling, wallopy effect. It is in no way anemic and neutered sounding, but possesses the right, real heft, where it needs to be. Tight, extendable, harmonic, pitch-precise and addictive, almost positively psychotomimetic low notes are so difficult to part with that it is possible to spend excessive amounts of time with these sounds and you crave for more.

- Sibilance Control

In spite of the fact that the IEM's can squeeze the “highest highs” of the recording, sibilance is magnificently mastered and controlled, resulting in monitors being untouched masters of hearing protection in an IEM.

- Soundstage and Imaging

Despite being an IEM, which is supposed to have “in-your-head” type of sound, T2PRO and T2i obviously share some of these characteristics, which are inevitable as the auricles (pinnae) do not take part in the process of creating the sound. The IEM's are, however, capable of producing sonic foreground and background, channel separation and are characterized by a very decent, magical handling of frontal imaging. Of course, there are full-sized headphones capable of producing greater and smaller soundsages. The “in-your-head” type of presentation, however, is incomparably and ubiquitously revealing every niceties of the recording in a meticulously crafted manner.

- Sound Signature Characteristics

It is more speaker like, similar to a combination of high-end tweeter and a bass driver, rather than a faulty misinterpretation of a full-sized headphone timbre. Smooth, velvety and relaxing being on a par with hyper-details and acute sensitivity. Characterised by overall timbral balance. Very real.

~ musical vs. analytical (attack, decay & instrument separation)

A holistic approach allows one to literally melt with the music. It is cohesive, non-mechanical oneness with music which makes you not only tap-toe to the rhythm of the music, it makes you dance your way up the Stairway to Heaven (pun intended, but I can't dance anyway). Without flaunting the details, which are anyway present to the uttermost degree I have ever heard, the sound is reverberated where it should be and the following notes come with the supersonic speed as/if was meant by the original recording. In a nutshell, attack and decay are mind-blowingly real and natural, and are limited solely by the limitations of a recording. The spatial, ultra-clear and tangible instrument separation is undoubtedly awe-inspiring to say the least. They do possess an uncanny fun factor and certainly find their place in the grooved Side of The Moon, but also have a binary, computed and analytical speed of a Firebird to boot. Solid, but never boring, capable of reproducing PRaT with ease of presentation.

Actual Usage

- Comfort, Isolation and Insertion

Once the IEM's are crafted from perfect ear molds, it is impossible to break the seal as the material adjusts itself according to the ear canal changing its shape. The special comfort-gel- silicone full shell is the über-alleviating and ultimate solution in terms of comfort of any kind. There is no possibilty that other manufacturers offer the same degree of long-lasting comfort (other IEM's and headphones included). In a word: the kings of comfort.

As every kind of IEM (especially custom-made), T2PRO and T2i require getting accustomed with proper insertion/removing techniques at the very beginning. Afterwards it is just pure pleasure. The IEM's provide 26dB of ambient, passive sound isolation. Both monitors I have are characterized by a faultless fit and isolation (as far as an IEM can go in this field).

- Hearing Protection

Both IEM's are the ultimate, professional solution for people with hearing protection in mind (no other professional, universal and custom IEM can compete in this territory); efficiently reducing all ambient sound by 26dB. Avoiding unwise listening volumes combined with pristine isolation and sibilance-free sound reproduction, gurantee safety and hearing protection. The ability to immerse the listener with the full sound spectrum right from the very beginning saves one from turning the volume up to too dangerous SPL levels. Using iRiver iHP 140 with Rockbox alternative firmware I can find the fully-fledged sweet spot with the volume set at about 40/50, or less, out of 100 (with the volume considerably stretched out in this firmware) and at about 4/5/6 out of 40, using the original iRiver firmware.

- ACS' Helping Hand

As can be expected from the professional company, every issue encountered by the owner of ACS' T2PRO and T2i will be resolved and fixed as soon as possible. One can expect an excellent product as people out there put their hearts and souls into their work.

- Warranty Policy:

From November 2005 ACS introduced a 2 year warranty for these products . Below is the older version of warranty:

~ 30-Day Remake Policy

ACS will remake, at no extra charge, all molds returned for poor fit within 30 days of purchase.

~ Limited 1 Year Warranty

ACS will repair malfunctionuing products that are a result of manufacturing defects, at no extra charge, for 1 year after the date of purchase.

~ Not Covered

•  Cable damage.
•  Failure or improper function due to wax in earpiece.
•  Damage to earpiece.
•  Modifications to earpiece by unauthorized ACS representative.

There are no refunds on any custom-made products.


Because of their low impedance, the IEM's can be driven by any source without the particular need of being umplified. It is a perfect coalescence of high-end analytical fidelity combined with awesome musical representation. For professionals and music aficionados alike.


If it can be considered a disadvantage, it can be hard to focus attention on something else besides certain recordings and the all-embracing, enchanting music.

Highly addictive (and I mean it).


- Associated Equipment

•  iRiver iHP 140
•  Ray Samuel's SR-71 (borrowed)
•  E-MU 1212m/ Ray Samuel's SR-71

Both IEM's evince an uncanny synergy with iRiver iHP 140 playing lossless (FLAC, WavPack, Shorten, etc.) out of the optical port. They are recording-dependent and revealing any artefacts of lossy and poor compression. The IEM's can handle the whole spectrum unequalized using this portable multi-codec jukebox. I have been listening unamplified as there is no greater need for an external amplifier when paired with this particular iRiver unit. When I amplified it with a borrowed Ray Samuel's SR-71, there was a slight improvement in timbre, but not big enough to consider using it on the go, in my opinion.

Testing Tracks Miscellany; a selection

•  A Perfect Circle- “Thirteenth Step”
•  Anathema- “A Fine Day to Exit”
•  Angelo Badalamenti- Twin Peaks OST
•  Colleen- The Golden Morning Breaks
•  Dave Matthews Band- “Before These Crowded Streets”
•  Depeche Mode- “Playing The Angel” + others
•  Jim Morrison- “An American Prayer”
•  Katie Melua- “Piece by Piece”
•  Led Zeppelin- “IV”
•  Moonspell- “Sin”
•  Nick Drake- “Bryter Layter” + the whole discography
•  Metallica- “Black Album” (SACD surround version converted into 48000Hz stereo WavPack) + the whole discography
•  Miles Davis- "Kind of Blue"
•  Nine Inch Nails- “The Fragile” (Vinyl version, 2CD's) + others
•  Nirvana- “MTV Unplugged In New York”
•  Pink Floyd- “Dark Side of The Moon” (SACD version converted into 48000Hz stereo WavPack)
•  Placebo- “Sleeping With Ghosts”
•  Porcupine Tree- “Deadwing” (DVD-A converted into 48000Hz stereo WavPack)
•  Ray Manzarek & Michael McClure- “There's a Word”
•  Sigur Rós- “Takk”
•  Stax Set-Up CD; Binaurally recorded using Dummy Heads ( NEUMANN KU 100 & NEUMANN KU 81)
•  Stereophile Test CD3
•  Tchaikovsky- “Firebird”
•  Tomaso Albinoni- Adagio For Organ And Strings In G Minor
•  Tori Amos- “The Beekeeper”
•  The Cure- “Blood Flowers” + others
•  The Prodigy- “The Fat of The Land” + others
•  Tool- “Aenima”


Product Downloads

Download the latest care and usage instructions

Download the latest product specification sheets

We'll keep your ears on file...

ACS is pleased to announce the introduction of a new state of the art scanning technology that means ALL customers that order custom made hearing protection and in-ear monitoring products from ACS will have their ear shape on file at ACS for up to 4 years. The device will scan the impressions and save as a file on the database so customers can order new products or replacements instantly without the need to have new impressions taken. What's more, this service will not cost customers anything extra on top of the standard product charge, it is just a little something we want to do to make your experience with us even more enjoyable!

Please be aware that the scanning service began on May 1st 2010 so will only apply to customers that ordered thereafter. 


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Please note - ACS products require good deep impressions in order to create a seal in the ear so it is important there is no wax block in the canal that will stop the audiologist from taking an impression. If you think you may have a wax build up, please visit your local GP for a consultation before booking an appointment with a dealer. You may be charged a fee if the audiologist is unable to take an impression. 

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