Westone Laboratories, Inc. was established in 1959. In the 1980s, they developed balanced armature drivers in custom-made earpieces and produced the first in-ear stage monitor.
The Universal Fit and Custom Fit earphones followed in 2002 and subsequently new product lines were offered, making high fidelity listening more accessible. After the acquisition by Lucid Audio in 2020 a new state-of-the-art customs lab was established and Westone’s products continue to evolve.
AM Pro X is the latest range of in-ear monitors produced by the company. The AM Pro X10 (“X10” hereinafter) is the first model in the series and features a single full-range balanced armature driver. It retails for $250.
The X10 comes in a fairly chunky box with a slip cover bearing a two-colour image of the product along with the company logo and description. Removing the slip cover reveals a plain white box emblazoned with the Westone Audio logo and the box opens with a magnetic tab. Inside, the earphones are stored in a foam cut-out with the cables attached, above which is the red plastic Mini Monitor Vault containing the rest of the accessories. The contents comprise:
● Westone AM Pro X10 monitors
● Linum BAX T2 cable
● 5 pairs silicone tips (XS, S, M, L, XL)
● 5 pairs foam tips (XS, S, M, L, XL)
● “Mini Monitor Vault” case
● Ear wax removing tool
● Cleaning cloth
Design and Build
The earpieces are formed from clear plastic allowing the balanced armature and internal wiring to be seen. The sockets for the T2 cable are positioned on the top of the capsule and have a pronounced forward rake. There is a red-coloured sound tube leading to the long narrow nozzle and a black boss in the centre of the faceplate bearing the Westone logo. The earpieces are very compact and lightweight.
The supplied cable is Westone’s proprietary Linum BAX design, a silver-plated copper cable with T2 connectors which are similar to MMCX but smaller. The cable is quite thin, and there is a rubberised Y split and chin slider which was welcome as the cable proved prone to tangling. The connection was stable and secure.
Fit and Isolation
The X10 needed to be placed perfectly horizontally and once in position, it fitted snugly inside my ear. The long nozzles and extended eartips produced a deep insertion which was very comfortable. I experimented with the supplied tips and obtained the best result with the largest silicone type with an orange bore. Thus fitted, a healthy bass response was obtained with good isolation, although external sounds still remained discernible. The long thin nozzles did not allow me to try standard IEM tips so “tip rolling” was not possible.
The X10 was tested initially with a Hidizs AP80 Pro X DAP. A running in time of 100 hours, using a range of musical genres and white noise, was allowed to settle in the components. However, this combination proved to be a little lightweight in nature so I changed to the more powerful Xduoo X20.
The extra power really helped to flesh out the sound, so much so that I experimented by adding a Fiio A5 amplifier via line out. This resulted in a more authoritative presentation with a solid foundation. The X10 handled the extra power admirably and I drove them to very high levels with no evidence of distortion. This was the combination used for the review.
Listening to the X10 was a surprise. I was not prepared for such a big sound from so small a device, especially from a single BA. Unlike previous IEMs with such a configuration I have heard in the past, the X10 demonstrated a wide response with good output at the frequency extremes.
Although a little reduced in level, sub bass possessed some rumble, the midrange was forward and detailed and the treble was clean, clear and well extended. Soundstage was expansive and spacious. The tonality was natural with no sign of “BA timbre” and the use of a single driver ensured great coherence across the range. There was a good balance between technical ability and musical expression.
Balanced armatures in general do not demonstrate the visceral bass of dynamic drivers. However the X10 produced good quality bass within its physical restraints. The low frequencies were powerful, fast and detailed with good extension and delivered exceptional transient attack with notes starting and stopping with precision.
The overall bass profile was generally linear and I felt a little more depth and weight would have been welcome here. However, there was some sub-bass presence and texture was well rendered. Mid bass was punchy and dynamic and there was a smooth transition into the midrange with no bleed.
Vangelis’s “Anthem”, the official theme for the 2002 World Cup, begins with a series of impressive drum strikes. These were reproduced cleanly with great impact by the X10, whilst displaying a natural timbre and decay. Throughout the track, even when things became complex, there was no sign of strain and there was plenty of headroom in the climaxes with the balance between percussion and the melody line well handled.
The late Pete Bardens was the keyboard player in the prog-rock band Camel. In 1981 he produced a single “Sailplane” under the name OBX, referring to the Oberheim synthesiser used in the recording. The piece features powerful electronic percussion which the X10 handled with slam, impact and depth. During the instrumental section the deep bass synth tones displayed excellent texture and detail, complementing the smooth string patches.
The X10’s clear and expressive midrange was slightly forward in nature and full of detail with a natural and accurate timbre. There was plenty of space around the instruments and vocals were particularly well rendered. The overall profile was neutral with just a hint of coolness in tonality.
The character of Colin Blunstone’s voice in his classic single “Say you don’t Mind” was beautifully conveyed by the X10 with lip and breath sounds clearly discernible and dynamic changes very evident. Set against a clever and imaginative string arrangement by Christopher Gunning, the balance between the vocals and the accompaniment was nigh-on perfect with the diction always precise, resulting in an entertaining and satisfying performance. The falsetto ending to the song was reproduced with excellent clarity.
The midrange demonstrated an accurate and natural timbre as evidenced in “En Skrift I Snöen” from Benny Andersson’s solo album, “Piano”. The X10’s authentic tonality made the most of the elegant flowing melody, enabling the listener to appreciate the quality of Andersson’s playing, with both the percussive and softer elements nicely portrayed and the ambience of Linn Fajal’s superb studio recording clearly audible.
The X10 displayed a smooth, extended treble with copious detail, fast transient response and a good sense of “air”. Sounds were well separated and cleanly delivered. There was no trace of harshness or “BA timbre”. The highest frequencies possessed an attractive sparkle and a natural quality endowing instruments with an authentic tonality.
Zimbabwean multi-instrumentalist Hennie Bekker has produced a large catalogue of music in the film music, jazz and new age genres. “Northern Lights” appears on his album “Winter Reflections”. Introduced by rhythmic sequencer samples and smooth synth patches, shimmering string chords emerge accompanied by sparkling electronic effects.
These were beautifully presented by the X10 forming a perfect backdrop for the ensuing melody line. Clarity and precision were the keywords here and at the conclusion of the piece the dynamic range was very impressive as the music swelled to its climax.
Bach’s famous “Toccata and Fugue in D Minor” received an astonishing recital from Helmut Walcha. The X10 certainly did the superb 1959 recording justice with the crisp and brilliant tones of the Silbermann organ at Alkmaar clearly reproduced with verve and precision.
The separation of the individual notes in the upper register was notable with excellent speed and attack and the lively and dynamic performance, with the soloist blind and playing entirely from memory, is surely a classic of its kind and was really brought to life by the X10.
Soundstage and Imaging
The soundstage was large and spacious with width, height and depth of approximately equal dimensions. At the same time, layering, separation and imaging were all of a high standard, which was quite a remarkable feat for a single BA unit. The positioning of elements within the stage was accurate and believable and movement across the stage was captured very convincingly.
The X10’s ability to handle complex and wide-ranging material was evident in “I am a Camera” by The Buggles. Trevor Horn’s superb production came over entertainingly with the vocals placed precisely over the spacious soundscape populated by electronic effects, studio reverb and Geoffrey Downes’s accompanying keyboards.
The sense of depth was particularly apparent, especially near the end of the track where Trevor Horn’s vocals are set deep in the stage. This was very effectively portrayed with a real sense of distance in the image. The final section features somewhat foreboding keyboard chords which produced an atmospheric and unsettling feeling.
Pink Floyd’s “The Division Bell” is one of their finest works. The instrumental track “Cluster One” introduces the album and begins with sound effects of burning wood, accompanied by Rick Wright’s airy keyboard accents. Dave Gilmour’s guitar follows in a conversation with the piano, and then Nick Mason’s powerful drums join in. All this was presented superbly by the X10 in an open and spacious manner with the instruments all clearly defined over an inky black background and the balance between the various elements well judged.
KBEAR Neon ($60)
KBEAR’s Neon is a “bullet” style IEM with a single BA driver, a high quality Knowles ED29689, which is more often employed as a midrange unit in a multi-driver configuration. The Neon is designed for deep insertion like the Etymotic brand and has a detachable 2-pin cable. The build quality is very good and feels more solid than that of the X10.
The Neon displays a mid-focused profile with gently rolled-off bass and a treble response which also falls off slowly with a moderate peak in the HF providing some “air”. It excels in vocal reproduction and has an attractive open soundstage. Bass is conservative in nature with a suggestion of, rather than actual, depth but displays good texture. This results in a light but gentle profile but it is lacking in body and impact in comparison with the X10.
The Westone sounds fuller, more dynamic and energetic, has a much more powerful bass and is more extended in the treble. The soundstage is even more expansive. It improves on the Neon in every respect except perhaps in vocals where things are very much on a par. Of course, the Neon is in a much lower price band, but it performs very well in its class.
Aiderlot M5 ($159)
The M5 is a multi-driver IEM with five Knowles BAs, a 22955 unit for the bass, one 29689 for the midrange, two 30017 drivers for the treble and a single 30095 BA for the extreme HF. The earpieces are very well made and the package is sumptuous. It has an MMCX interface.
The M5 has a neutral/flat “reference” tuning which can be adjusted using the three supplied tuning nozzles. For this comparison I fitted the “bass” filters. Thus equipped, bass was linear and resolving, midrange clear, open and detailed and treble smooth, precise and very extended.
Compared to the X10 the Aiderlot is more measured and reserved but still accurate and neutral. The X10, on the other hand, is more dynamic and immediate yet still remaining true to the original source. It is more transparent and, as intended, can “see” into a recording and reveal the finest detail without losing sight of the music.
Westone’s experience with musicians has certainly paid off with the AM Pro X10. Many earphones on the market are described as “monitors” but the X10 really does deserve the epithet. The accuracy, detail and natural timbre gets very close to the original sound, as is the intention and the details of productions are laid bare.
The X10 comes attractively packaged with a generous set of accessories including a proprietary T2 cable. I would have liked to see a modular cable included to facilitate balanced operation, which I was unable to test on this occasion. Many audio enthusiasts have a collection of MMCX and 2-pin balanced cables, but few own the T2 version and modular types are now becoming more commonly included with IEMs at a lower price than the X10.
On first seeing the earpieces, I considered them somewhat unprepossessing, and with their lightweight construction I felt they did not convey a sense of perceived value. That was until I placed them in my ears and pressed “play” and then the magic happened. Previously unheard details in familiar tracks became audible and the balance of recordings was presented in a way which encouraged me to listen again with new ears.
I was amazed at the performance Westone managed to squeeze out of just a single BA driver and, despite the physical limitations, how full and satisfying a sound was produced. As a single BA IEM, the X10 exceeded my expectations and while $250 may seem a fairly high price to pay, when the standard of performance is taken into account, it becomes more reasonable.
If you enjoy smaller-scale works such as chamber music and vocal-based material the X10 will be ideal but lovers of bass-focused genres and large-scale classical works may need to apply a little EQ. It needs a healthy signal to give of its best and paired with a powerful source, it performs very well indeed.
Possessing a well-tuned neutral and accurate profile, it is the perfect tool both for on-stage monitoring and musical enjoyment and is warmly recommended.