ACS is renowned worldwide for its custom in-ear monitors made of soft silicone. To let potential customers hear the sound quality of different models, we developed demo earphone units to allow customers to listen to the intended sound. The demo unit must achieve a proper seal with the customer's ear canal to block outside noise and prevent sound leakage because these two factors can alter the sound quality experienced by the customer and influence their purchasing decision.

To achieve the best possible listening experience, we constantly improve our listening devices based on customer feedback. As a result, many of our customers have found the demo device easy and comfortable to wear, and the music sounds remarkable. Many even asked if they could buy them directly. This level of feedback and interest prompted us to convert the demo unit into a new range of universal in-ear monitors.

客製耳機的主體是按照個人耳廓的尺寸和形狀製作；客製耳機的耳道端的長度、大小和形狀也是根據使用者的耳模來訂製，因此客製耳聽能夠提供最佳佩戴感和音質，但是缺點是它的成本高，容易故障，而且不能轉賣給他人。

通用監聽耳機，可以擁有與客製耳機相同甚至更優秀的音質，任何一隻通用耳機都可找出一群人能夠完美佩戴，甚至達到媲美客製耳機的佩戴感和隔離度。但是，一般來說高音質監聽等級的耳機，因為內部安裝多單體，通常耳機殼體變大，而且大多數通用耳機的生產商，並不製造客製耳機，因此他們缺乏對耳朵和耳道的深入了解。常常會引用公版的通用耳機殼做些微修正來容納內部零件，配上一個特製的前蓋而完成。這類耳機往往會因耳機本體尺過大，無法戴入耳廓。或是耳機本體一部份懸掛在耳廓外，無法穩固等等問題，導致不能使用的困擾。

1. It must offer the broadest possible wearer compatibility so that the widest possible percentage of people can comfortably wear the new monitors.

2. it must provide outstanding product durability, ease of use, and personalization. 

3. Combine the advantages of dynamic and balanced armature drivers to create a product that satisfies music lovers' desire for top-notch musicality and is suitable for all types of music. At the same time, it meets the monitoring needs of professional musicians by providing them with in-ear monitors ideal for creative work and live performances.

We prioritize wearability because if people can't wear our monitors comfortably, it doesn't matter if we achieve our other goals.

We used 3 different lengths of output tubes and 7 different sizes of foam and silicone earplugs to achieve 21 different (Personal Adaptive Wearing Combinations).

Users can use foam or silicone earplugs to apply different pressures on the ear canal. The resilience of the two different materials enables them to utilize a large sealing area for a comfortable and tight fit. 

This prevents external noise from penetrating the ear canal and the sound from leaking out of the headphones, allowing the user to hear the quality of the music from our monitors.

The new Universal Monitor series consists of 3 earphones. FLAIR and VIORA use a hybrid architecture with one dynamic coil and three balanced armature drivers, while UNA is a single dynamic coil architecture.

LIVE SOUND Filters
All three earphones are equipped with the ACS LiveSound filter, which releases ear pressure and reduces eardrum fatigue caused by prolonged wearing of earphones, avoiding the risk of hearing damage caused by constant volume increases due to fatigue; it also reduces the occlusion effect of wearing in-ear headphones with the ear canals completely sealed (one's voice rumbles and reverberates) and provides a sense of airyness of sound. LiveSound also provides a sense of sound ventilation. 

In addition, LiveSound allows users to hear attenuated external sound without removing the earphones simply by lowering the volume. If the volume is adjusted to be louder than the external sound, the user can enjoy the music while remaining aware of the outside world.

FLAIR Universal In-Ear Monitors for Music Lovers
Both FLAIR and VIORA use the same 4-driver structure, and both are tuned according to ACS's professional music lineage based on their ability to accurately reproduce the original's actual music. Their difference lies in the tuning attributes. 

FLAIR employs elegant creamy white housings with mirror-finished rose gold color faceplates, with a brand new cable that uses four 4N-OFC silver-plated Litz wires, double twisted then braided to form, delivering uninterrupted audio transmission. FLAIR has a single dynamic and three balanced armature drivers, each handling low, midrange, high-midrange, and ultra-high frequency bands. All monitors in the new series incorporate ACS LiveSound filters as a part of the integral core "Vented Tuned Resonance Chamber," engineered to control the frequency response subtly.
 

VIORA Universal In-Ear Monitors for Music Professionals
VIORA is a special version for professional musicians and artists, featuring a subdued matte black chassis with a mirror-polished glossy silver faceplate, a new black cable, and a 90-degree 3.5 plug suitable for inserting into wireless monitor receivers for eye-catching effects during live performances. Professional musicians use earphones for long periods at work, so we've included the ACS Revivo2 monitor dryer and 3.5 to 6.5mm adapter. VIORA also comes with a set of full isolation plugs to replace the LiveSound filters for when the musicians also have stage monitor speakers during their live performances, stopping the stage monitor from leaking into the earphones.

The appeal of VIORA is that once the musicians and singers put on the VIORA during a live performance, they can hear their own monitoring needs without making any special adjustments at the console. It is tuned like the FLAIRs but is given a high dynamic range and quicker response without becoming shrill. Vocals and midrange are slightly front-loaded, accurately boosting instruments and vocals and dovetailing perfectly with the powerful, big-speaker-flexible bass. The mid-highs and ultra-highs are the same as the FLAIR, with a transparent, expansive soundstage that delivers the accuracy and musicality needed in the field and the studio and better suits the monitoring needs of music professionals.

UNA Preferred Music Grade Universal In-Ear Earphones
The UNA is a single-dynamic earphone featuring a 10mm dynamic unit custom-built for ACS. It is housed in a solid matte black chassis with a matte black faceplate and four 4N silver-plated OFC Leitz cables twisted into a rope-like shape. The cables are threaded through a metal Y-branch to form a twisted-pair cable that runs through the 2PIN plug on each ear. The other end of the cord is fitted with a straight metal casing and a gold-plated 3.5 jack plug.  

UNA has a powerful and sexy low end, bright vocals and midrange, and a high end with details beyond the level of a typical dynamic earphone. Combined with the unique airiness provided by the LiveSound filters, UNA delivers vivid and powerful audio, whether listening to music, playing a game, or watching a movie.

2025 new series of universal monitors use the previous generation of ACS memory foam earplugs; it uses medium density foam, is comfortable to wear, and provides proper pressure, forming an excellent seal with the ear canal isolation ring. The diameter of the foam is L: 13.5, M: 12.5, S: 11.5mm, and the height is 10mm. Inside the earplug is a silicone tube to avoid absorbing and affecting the audio; the tube is made with blue, white, and red colors to identify the earplugs' L, M, and S sizes.

Unlike its predecessor, we have added a set of silicone earplugs to the new series of headphones. This set of earplugs has four diameters: L: 13, M: 12, S: 11, and ES: 10.5mm; the height of L, M, and S is 11.5mm, and the height of XS is 10.5mm. The inner part of the earplugs has different bumps: four bumps for L, three bumps for M, and so on, making the earplugs easy to recognize.
The difference between our silicone earplugs' long cylinder structure and the common umbrella or half-round ball shapes is that it can form a larger sealing ring with the ear canal, the same as the foam earplugs, which optimizes isolation and enhances stability.

Both sets of earplugs can meet customer preferences and needs; we select them to express better the excellent musicality of the new series of monitors. Although the size of the two sets of earplugs is not very different, due to the difference in the resilience of the materials, the actual wearing sensation is very different. Mixing the three lengths of the output tubes and the resilience of the earplugs' materials, you can feel the effects of the various combinations on the wearing comfort, the sense of stability, and the closed isolation.

How are Monitors different from Earbuds, Earphones?

Their main differences are in design purpose, target users, performance characteristics, and price.

Used by professionals such as musicians, singers, audio engineers, and audiophiles, UIEMs are specially designed to produce flawless music with a high degree of comfort and isolation while wearing them. Musicians need to hear with high accuracy on stage or in studio environments, and audiophiles seek to listen to what they recognize as perfect detail. The purpose of monitors is to provide a perfectly balanced sound that blends precision with quality musicality, hence the higher price of a UIEMS.

Earbuds (Earphones) are convenience-oriented devices for the average consumer who listens to music, podcasts, or movies on the go and are therefore less expensive. These headphones usually emphasize bass frequencies to compensate for the loss of bass due to sound leakage. The human ear is very insensitive to low frequencies; therefore, when the earbuds of a headphone do not make a good seal, the sound from the headphone leaks out, reducing the overall loudness, thus exacerbating the problem of the human ear's low sensitivity to bass, and as a result, the bass becomes noticeably deficient.

Emphasizing the low-frequency output volume compensates for this loss and, at the same time, makes the music sound livelier and more rhythmic and, therefore, more "fun" to listen to.

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