Westone Laboratories, Inc. was established in 1959 by Ron Morgan in Colorado, USA. With a background in audiology and hearing health, the company specialises in hearing aid technology as well as serving the professional audio equipment market.
In the 1980s, they developed balanced armature drivers in custom-made earpieces and produced their 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 with the current product inventory focused on the Pro X and MACH ranges of IEMs.
The MACH 70 featured here is the second highest model in the series, equipped with seven balanced armature drivers per channel, one for the bass, two for the midrange and four for the treble region. A three-way passive crossover divides the signal amongst the seven drivers. A frequency response of 5Hz-22kHz is specified along with an impedance of 42Ω and a sensitivity of 110dB @ 1kHz. The MACH 70 retails for £1399.
The Packaging
The MACH 70 comes in a large rectangular box with a full-colour sleeve featuring a montage including an image of the IEMs and the model name MACH 70 displayed in a modern sans serif font. The rear of the box shows the specifications and a list of the contents. Removing the sleeve reveals a black box bearing the Westone Audio logo and the legend “Inspired by Lucid Hearing”. Within you will find a large black pelican case inside which there is:
● Westone MACH 70 IEMs
● Estron Linum UltraBaX T2 cable
● 5 pairs of foam tips
● 5 pairs of silicone tips
● Carabiner
● Soft protective bag
● Velcro cable tie
● Cleaning tool
● Card with QR link to manual
Design and Build
The MACH 70 IEMs have a shell made from a durable plastic material in black and grey. The faceplate is metal with the right side featuring the Westone logo and the left bearing the model name MACH 70. The gold-plated T2 cable socket has a pronounced forward rake and the earpieces are lightweight and comfortable.
The Linum UltraBaX cable has a 4-core construction with 224 strands of silver-plated copper. The T2 termination and right-angled 3.5mm plug are gold-plated and the two-part Y-split detaches to provide a chin slider. The cable is approximately 1.2m in length and is very light with a weight of 9g. Bearing in mind the price level of these IEMs, I was disappointed that a modular cable was not included, which would have facilitated balanced operation.
Fit and Isolation
Once the MACH 70 was placed perfectly horizontally, it fitted snugly inside my ear. The long nozzles and extended eartips produced a deep insertion which was very comfortable and after a short time it was easy to forget that the IEMs were there. 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 superb isolation. Westone’s long thin nozzles did not allow me to try standard IEM tips so “tip rolling” was not possible.
The MACH 70 was tested with a variety of sources: three different DAPs, a digital radio and a smartphone via a USB-C dongle DAC. A “burn-in” period of 100 hours was performed to run in the components. Initially, there was a “veiling” and some hint of muddiness but this disappeared after 24 hours, after which the sound opened out and became clearer. The sound continued to improve throughout the burn-in period.
Sound Impressions
Tonality
The MACH 70 impressed immediately with a warm, rich and full delivery. The bass was deep and impactful, possessing a natural timbre and decay more usually associated with a dynamic drivers, whilst retaining the speed and attack of a balanced armature. The midrange was natural and open with vocals being particularly well-rendered.
There was plenty of detail, notable separation and an authentic timbre, especially on acoustic instruments. The treble was silky-smooth with copious detail and displayed very good extension with an ethereal, airy quality which was very easy on the ear. Staging was very expansive and spacious with accurate reproduction of recorded ambience.
I was struck by the overriding sense of effortlessness and refinement in the presentation with a natural perspective and the seven BA drivers acted as a single unit with a seamless transition between them. There was a healthy output with adequate volume obtained from all sources and the overriding impression was one of musicality and realism without being too analytical.
Bass
Balanced armatures do not often match the “slam” and visceral quality of high quality dynamic units but the MACH 70 turned that theory on its head. The single dedicated bass BA delivered deep, solid and powerful low frequencies with excellent resolution and natural tonality. The atmosphere of recording venues was reproduced convincingly, creating a believable impression of a live performance.
In the fourth movement “Affirmation” of Roy Harris’s 6th Symphony (Gettysburg) with the Pacific Symphony Orchestra under Keith Clark, the MACH 70 produced a realistic panorama of the players in the hall. Towards the end of the movement the tempo increases with syncopated strings and brass and a prominent use of percussion.
The orchestral bass drum is used dramatically in the finale and the initial strike, rebound of the skin and decay were all authentically presented in an impressively unforced manner, evoking a real visit to a concert with the quality of the superb Soundstream recording vividly brought to life.
“Distant Dreams” is an album of electronic soundscapes by the Dutch artist, The Amnis Initiative. “Sail the Cosmic Ocean” begins with a deep synth bass foundation accompanied by delicate electronic effects. Soon the main theme appears and powerful accents in the bass add drama. These were effectively portrayed by the MACH 70 with impact and depth, supporting and enhancing the uplifting anthemic melody with the textures in the low frequencies convincingly realised.
Jeff Wayne is perhaps best known for his concept album based on H.G. Wells’s “The War of the Worlds”. He also produced David Essex’s album “Rock On”. The title track is arranged in quite a radical way. Unusually, there are no instruments playing a chord in this stripped down arrangement which is driven along by Herbie Flowers’s double-tracked bass guitar supplemented by percussion and David Essex’s vocals creatively placed around the stereo image.
The bass guitars were reproduced wonderfully well by the MACH 70 with excellent texture and depth, displaying a characteristic “growl” and the separation between the kick drum and bass was very well handled.
Midrange
With very little recession, the MACH 70’s midrange was open, expressive and approximately at the same level as the upper bass, deriving some warmth from that region. This suffused the lower midrange with an attractive bloom without adding adverse colouration. The tonality was consistent up to the boundary with the treble and there was only a minor amount of “pinna gain” thus avoiding harshness and sibilance. Vocals were particularly well presented with precise diction and the soloists were projected clearly in front of the accompaniment.
“Brother up in Heaven” is a track from “On Air”, a concept album by The Alan Parsons Project, inspired by flight. Neil Lockwood’s soulful vocal was beautifully presented with the emotion of the lyrics conveyed effectively and breath and lip sounds adding to the realism. The lead vocal was perfectly balanced with the instrumental arrangement in a vibrant and detailed production.
Cellist Adam Hurst’s “The Secret” is an album of pieces accompanied by various other instruments. In “Red Sky” Hurst is supported by the Array Mbira, an African instrument similar to a kalimba which produces clear, bell-like tones. The contrast between the legato bowing of the cello and the incisive plucking of the mbira was portrayed by the MACH 70 with the natural timbre and “rosin” of the cello complementing the sustain and decay of the mbira’s pure notes in captivating style.
Debussy’s “Suite Bergamasque” for solo piano is a classic of his Impressionistic style. “Clair de Lune” is a romantic evocation of moonlight on the sea. The superb recording by Ikuyo Nakamichi was beautifully reproduced by the MACH 70 with a natural timbre. In the first part the pace was fairly slow, allowing the bass notes to decay and support the right hand with rich overtones.
Later in the piece there is a more animated section and the rapid arpeggios were rendered accurately with each note precise and separate and remaining discernible even when forming the accompaniment to the principal melody. The conclusion returns to the style of the opening with the final notes decaying very naturally.
Treble
The four treble drivers working in concert produced a smooth, detailed and extended response. There was no trace of harshness or sibilance and the commonly-found “BA timbre” was totally absent with the tonality being airy, natural and clean. Resolution was on point and the highest frequencies were delicate and ethereal.
“Petite Fleur” appears on the album “Land of Enchantment” by German multi-instrumentalist Georg Deuter, whose New Age music is chiefly inspired by Eastern mysticism. The piece begins with a plucked synthesiser melody line resembling a music box. As the track progresses the accompaniment becomes more dense. Throughout the piece the high frequencies were crisply defined with good transient attack and well separated, especially in the fast arpeggios, with the sparkly electronic effects adding interest and each element occupying its own space.
The MACH 70 proved itself able to combine musicality with technical prowess. In the “English Elegy” by Roland Roberts, the solo violin displayed a natural timbre with a fine reproduction of tone whilst delivering a mellifluous and musically satisfying performance.
The City of Oxford Orchestra with the composer as soloist was presented in a natural acoustic and the section in which the violin melody was taken up in succession by cor anglais, flute, horns and strings was particularly notable with the harmonics in the high violin notes beautifully reproduced.
Dave Brubeck’s classic “Take Five” really showcased the treble performance of the MACH 70. The chordal piano rhythm set the scene, followed by the breathy sax solo. Supported by resonant double bass, the realistic metallic tonality of the cymbals propelled the piece along. Joe Morello’s wonderful drum solo further underlined the quality of the treble reproduction with clean and crisp snare drums while the superb resolution revealed high frequency elements in the tom-toms.
Soundstage and Imaging
The soundstage was perhaps one of the best features of the MACH 70. It was broad and spacious with pinpoint imaging yet did not exaggerate the dimensions of the stage. Positions of instruments and performers were presented realistically and in correct relation to each other. Layering was of a high standard, making it simple to follow individual strands and there was a good sense of perspective.
The Pale Fountains were a New Wave band from the 1980s. “Just a Girl” recorded in 1982, has a superb production, with a variety of instruments being featured alongside Mick Head’s characterful vocals. There are cameos for trumpet, violin and acoustic guitar which are expertly woven into the production and they were clearly presented by the MACH 70 with each instrument located precisely in various parts of the stage with stable imaging. The acoustic rhythm guitars occupied each side of the image, helping to focus the lead vocals in the centre.
Arthur Bliss’s “Melee Fantasque”, composed in 1921, is a ballet score full of colour and interest. Syncopated rhythms, brass, woodwind and percussion combine to form a busy and dense introduction and the MACH 70 was able to separate out all the various elements into a coherent whole while at the same time enabling individual lines to be followed.
The ambience in the wonderful Lyrita recording by the London Symphony Orchestra under the composer’s baton was palpable and the transient attack on the timpani in the central section thrillingly portrayed. Mysterious chords bring the piece to a close with a doleful atmosphere which was very convincingly conveyed.
“You Raise Me Up” by Secret Garden begins with Fionnula Sherry’s solo violin playing the melody line in a reverberant acoustic. Following this, Brian Kennedy’s soulful vocal takes centre stage and the MACH 70 presented it extremely clearly, conveying the feeling of the lyrics perfectly. The main theme is then taken up by the distinctive sound of the Uilleann pipes which displayed an authentic timbre and towards the conclusion the Anuna choir, supported by full orchestra, sing the chorus. The effect here was thrilling with the whole stage filled with sound, enveloping the listener and giving a believable impression of a large concert hall space.
Conclusion
I found this review particularly challenging to write because of the MACH 70’s musicality. I was frequently so captured by the music that I forgot to make mental notes on the technicalities and was forced to listen to the track again! From this experience, I can understand why Westone IEMs are popular amongst musicians.
The ’70 delivers music in a mellifluous yet decisive manner with a well-contoured profile. The bass is gently emphasised with a little extra warmth, the midrange is natural, open and displays a consistency of tone throughout and the treble is smooth yet deceptively detailed with excellent extension. On top of this there is an expansive and realistic soundstage with top-class separation and layering.
The whole is greater than the sum of its parts with the seven drivers appearing to act as a single unit, delivering a coherent sound across the spectrum with a level of refinement not found in lesser-achieving models. No matter what the genre, the MACH 70 presented it in an enjoyable and vibrant manner with musical enjoyment at the forefront yet not lacking in technical ability. Being at the top of the MACH range, it is a considered purchase but the results speak for themselves and it must be regarded as good value.
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