Home » Reviews » Bluetooth » M5-TWS Custom Review – Pioneer

M5-TWS Custom Review – Pioneer

Pros –

Unrivalled custom fit and isolation for TWS, Outstanding balance throughout and accurate timbre, Best in-class soundstage and resolution, Excellent build and finish

Cons –

Power and charging functions hamper convenience, Lower-treble spike may irk some, Background hiss, Call quality below average, No official IP rating, Costly

Verdict –

The M5-TWS Custom lies at the pinnacle of TWS sound quality, tuning and fit, but expect to pay a hefty premium to obtain it.

Introduction –

ADV. really came out of nowhere in 2015. They began life crowd-funded by Kickstarter but soon made a name for themselves with their very affordable products that focussed on the fundamentals and essentials. However, through collaboration with esteemed industry veteran AAW, the company soon set its eyes on the high-end scene, releasing a sophisticated line of customs and a planar magnetic headphone. They assume advanced manufacturing processes such as 6-axis CNC milling and 3D printing in order to realise these products. The M5-TWS was a departure from their usual designs, sporting the same audiophile focus but in a true-wireless form factor. We walked away very-impressed by its clean Harman-target tuning and immaculate 3D printed housings. The company didn’t stop there, however, releasing the M5-TWS Custom which represents more than just a custom variant of their previous TWS hit. It sports a new “reference” tuned driver and reworked acoustics alongside representing quite possibly the first full-custom TWS design on the market.

The M5-TWS Custom is available for $499.99 USD from ADV. at the time of writing. For more details, customization options and purchase, see ADV.’s website here.

Disclaimer –

I would like to thank Hannah from ADV. very much for her quick communication and for providing me with the M5-TWS Custom for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.

The Pitch –

Custom 3D-printed design

ADV. use 3D printing to achieve a high-quality acrylic construction and speed up turnaround times on custom products. This also opens the avenue for use of digital ear impressions that greatly aid convenience during the ordering process and permit the user to reuse the same impressions for years to come. Furthermore, the intricacy permitted by 3D printing means fewer cosmetic imperfections, more control over acoustic design and better channel matching for custom products, very important for imaging performance.

Reference-tuned PHPC Driver

The M5-TWS Custom uses a similar 6.1mm pressurized high-purity copper dynamic driver as the universal model. This means a tight, well-damped micro driver with an agile transient response whilst upholding an authoritarian sub-bass due to the enclosure that increases low-frequency pressure. However, the company has retuned the custom model specifically to follow a different curve. Where the uni was tuned to match the in-ear Harman target curve, the custom is reference-tuned that promises to be more neutral and transparent. I will touch more on the specific difference below.

Customization –

You don’t receive the same level of customisability as most custom wired earphones, but a select range of set designs; black burst, green ash and red pearl. Besides this, the company only offers different options in delivering your impressions, able to ship impressions, email 3D STL files or visit ADV’s lab in Santa Cruz. Alternatively, if you’ve ordered custom products from the company in the past, they’ll have your impressions on file.

Turnaround and Support –

I will firstly thank the ADV. team for their support during the global pandemic which has complicated production for many companies. The company promises a 4-6-week turnaround and this is in-line with my experience, my unit taking about 6 weeks to prep from when I first sent my digital impressions. It later came to my attention that the impressions I sent had a flaw necessitating 0.5mm bolstering of the left sound tube and ADV. were very helpful here too. The company was able to modify the earphones to my specification and shipped them out 2 weeks later by DHL Express which sped up the process.

Unboxing –

The M5-TWS Custom comes with markedly different packaging to the universal, more in-line with a CIEM. Sliding off the top cover reveals the earphones within a sleek CNC aluminium case with foam inlet that holds the earphones. Of note, the earphones utilise plugs on the faceplate for charging since the custom design does not permit docking in a universal case. The company includes a tiny type-C cable that charges the earphones alongside a compact Type-A to Type-C adaptor for use with ordinary chargers and older computers. The M5-TWS Custom’s case has no smart features or ability to charge the earphones. A smaller case with tighter inlet would have been a welcome addition, something like CFA’s IEM pouches that are much more pocketable and separate the housings to prevent scratches.  

Design –  

In handsome red pearl, my unit is very visually distinct and represents a high level of construction quality. Being a custom-made earphone don’t expect premium material choice here as conventional 3D printers only work with acrylic at present. I have been gushing about 3D printed products lately but do take note that not all are created equal. The particular company ordering or printing the products has full control over the resolution and finish at the cost of time, and ADV. clearly spend a bit more achieving a refined product here.

In turn, the finish and build are as good as you could hope for, each surface is perfectly smooth and this was especially noticeable to me when lighting the earphones where we observe very clean lines and contours. There are no seams due to the 3D printing, leaving a flawless unibody construction that feels light but solid. The transparent bodies showcase the acoustics and circuitry inside with mic cut outs interestingly positioned at the rear and a small vent at the very top. Take note that the M5-TWS Custom has no IP rating so use these for exercise at your own risk.

Fit & Isolation –

The M5- TWS Custom is about the size of a regular CIEM plus another millimetre of depth for the electronics. This makes it quite a bit larger than the regular M5-TWS but may vary based on your individual ear anatomy. Still, they aren’t especially low profile meaning that they won’t be suitable for wearing underneath a motorbike helmet or sleeping as our readers often ask about. As far as comfort is concerned, however, the size is of no consequence since they conform perfectly to the shape of your ears – given that the provided impressions were taken correctly. And indeed, this was the case for me; the M5-TWS custom disappears in my ears, providing perfect fit, seal and long-term comfort. They lock into the ears very well with slightly more articular fit around the anti-helix as opposed to my wired CIEMs, that greatly aids retention in the absence of cables and ear guides.

During workouts and commute, the earphones required no adjustment and I encountered no other fit stability issues. They were perfectly comfortably during longer listening sessions. Due to the rigid acrylic design, I did not find them ideal for running, however, where the constant motion would cause them to lose seal. A universal earphone with silicone Eartune fidelity/custom tips are a better option for this sort of application if a personalised fit and high levels of isolation are required. Despite visible vents, they isolate similarly to my sealed CIEMs. They also block the most noise of any TWS earphone I’ve tested ANC or not – nothing beats a perfect seal. The ear-filling design provides especially strong attenuation of low-frequencies which works well in tandem with their more balanced sound tuning. This will make these earphones an excellent companion for frequent fliers and travellers.  

Usability –

Pairing and Connectivity

The experience here is similar to most TWS earphones. After power on the earphones, they enter pairing mode. ADV. add a custom Bluetooth ID to match the user’s name here, ensuring that they are never confused with other devices. They quickly reconnect with previously paired devices but go back into pairing mode if that device is unavailable. The faceplates can be held for 5s to force pairing mode, audio cues let the user know when this is occurring. Utilising Qualcomm’s QC3020 chipset, the earphones support BT5.0 including Apt-X and AAC. This also means they can be paired independently which I was able to confirm, handy for extending battery life during mono calls for instance. Once connected, the M5-TWS Custom provided reliable connectivity. I experienced no dropouts between either side nor to the source device. Connection was also stable in crowded areas such as Sydney CBD which is generally most taxing for a wireless product. Range is also on the higher side, stretching through two rooms with double brick walls before becoming intermittent. With a line of sight connection, range was higher.

Charging and Battery Life

The M5-TWS Custom surely provides a markedly different experience here compared to your average TWS earphone. For one, the user must manually power the earphones on and off in the absence of a charging case via a 7 second hold on the touch-sensitive faceplates. In the same vein, charging is done via a Type-C cable, again affecting convenience. The upside is that, due to the compact size, it is very unobtrusive and enables the user to charge the earphones directly from a smartphone with Type-C connector. It seems reasonable given the nature of the product though potentially the company could have included a charging case that interfaces with the flat faceplates that will invariably by similar between all users.

Battery life is rated at 8 hours down from 9 on the universal. Given that the driver is actually slightly more sensitive, it is possible that the earphones have a more powerful amplifier. In real world usage, at around 40% volume, I found the earphones to meet that figure comfortably and reliably. I also feel that the absence of constant trickle charging may be beneficial for battery health long-term – though, of course, the user will have to remember to keep them topped up. From empty, ADV. quote that the M5-TWS Custom will take 2 hours to charge. They also state quick-charge support though they don’t quote any exact figures. In 15 minutes, I was able to charge from critical battery to approximately 40% which represents just over 3 hours of listening time. They also auto-off after 5 minutes to save power.

Touch Controls

The M5-TWS Custom utilises similar touch controls to the universal model. As they have a more stable fit and larger, flatter faceplates to interface with, the experience is somewhat better here. Furthermore, the controls have been slightly altered to now include volume control and smart assistant functionality as seen pictured below.

I personally am not a fan of the volume controls, however, since the single tap is easily mistaken when adjusting the earphones in the ear. Fortunately, they only change one step at a time, so you don’t have to worry about ramping volume up to a deafening level unintentionally. The touch controls aren’t as responsive nor as accurate as the Pixel Buds or Sennheiser MTW2 overall, but I experienced around 90% accuracy during my testing and didn’t find them frustrating during daily use.

Call Quality

Call quality was mostly similar to the regular M5, meaning good volume but some slight muffling here due to the rear-facing microphones. In quiet environments, users reported good vocal intelligibility. However, there is minimal ambient noise cancellation similar to the M5, if at all as recipients noted that ambient noise and wind were quite intrusive during calls. This will not be the best choice for those interested in the highest call quality but will do in a pinch, especially in quiet environments.  

Background Hiss

Whether due to the increased isolation, the more sensitive driver or revised circuity, the M5-TWS Custom has a reasonably pronounced background hiss that is clearly audible in quiet environments. It was more prevalent than the other TWS models I’ve tested so far, though again, isolation is substantially better making it appear more apparent. It was also slightly more prominent than on the universal M5-TWS. If you are sensitive to hiss, this will not be the best solution for you. However, most users shouldn’t find it too bothersome when music is playing.

Next Page: Sound, Comparisons & Verdict



Ryan Soo

Ryan Soo

Avid writer, passionate photographer and sleep-deprived medical student, Ryan has an ongoing desire to bring quality products to the regular reader.


2 Responses

  1. Hey Brian,

    I wouldn’t say any TWS earphones hold up to the sound quality of a midrange custom yet alone a high-end model like the Spiral Ears 5 Way. But, among them, this is near the best for sure.

    These ones don’t have a transparency mode. You may want to investigate the new Lypertek Z7 as it has both of these features and great sound quality – if you don’t mind a universal fit.


  2. How would this compare to Spiral Ears 5 Way Ultimate? Microphonics are starting to really ruin an otherwise good listening experience and I figured going True Wireless would be the best way to solve the issue.

    Does this also have a transparancy mode?

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