QUESTYLE M18i: Questyle’s New Generation Portable Headphone Amplifier

QUESTYLE is one of the well-esteemed audio companies around as they brought forth some of the highly acclaimed audio equipment that are used on both professional and non-specialised side of audio appreciation. Their well-regarded reputation as producers of high quality audio products assures that every product that they release on the market will be solidly built, easy to operate and will have some excellent components sourced from reputable audio solutions.

I previously published a few products from them and all of them are from their M series line-up models which are all portable headphone DAC/Amplifiers also known as USB DAC dongles. And now, what I have here and will be the highlight of this product review is the latest generation of the M Series models, The QUESTYLE M18i.

Unlike the previous models which are more of a standard portable headphone DAC/Amplifiers, this one has some new features that makes it more advanced as QUESTYLE added some of the latest breakthroughs of mobile audio innovation, particularly on wireless technology. And with some added features, this device is relatively a bit larger just to accommodate some functionalities that will deliver  a worthwhile audio experience.

The QUESTYLE M18i still shares some similar design language and form factor with the previous M-series albeit it incorporates a screen beneath on its tempered glass panel, an extra USB-C for charging (yeah, this is quite a unique feature) and finally, some physical buttons. The overall frame itself is made of a high quality CNC-milled aluminium alloy that underwent an anodisation and sand-blasting process to achieve its matte-like finish on its surface for better grip, less fingerprint magnet and resistant from light scratches, and like all M-series, it has black colourway with rather minimalist design on its aesthetics.

At the front part where the glass panel was situated, its appears that like M-series, it uses a tempered glass panel provide by Kunlun and beneath of it was a OLED screen panel in which display a simple UI for volume control, gain mode, battery level, sampling rate with its audio signal format  and device modes. On the back part, there are no other hardware features aside from the Questyle brand and the brand model print that was etched on it.

On the long side panel, there is a USB-C port (input charging only)  that supports USB charging while using the other USB-C port for decoding at the same time which is more convenient in my opinion. And at the opposite length panel, there are some hardware key buttons for volume controls and gain/MFB mode and a power button along with toggle switch for device modes for PC, Mobile and Bluetooth DAC/Amp connectivity as it has an advanced optimisation for power supply for reduced power consumption for each specific mode along with a built-in mic input. The buttons also support some basic media playback controls like play, pause and next via double pressing on playing tracks, and also on calls like answer, reject and disconnect.

The gain mode, we can switch on either low gain more or high gain mode while its volume amplitude rating can deliver up to 60 steps with an incremental adjustment on each level. On the power button, if we press it, it will be on the stand by more which makes the UI print a bit dimmer.

And then, at the side vertical angle part, like most of the previous generation of M-series, it has a dual headphone jack set-up of varying output types, a standard 3.5mm single-ended and a 4.4mm balanced output. And on its opposite side, this is where the USB-C port can be connected to other devices with compatible connectors, like smartphones, tablets, laptops and PCs along with other devices as long as it supports USB audio.

Unlike the top models of the M-Series that uses a flagship USB DAC, The QUESTYLE M18i uses a rather standard ESS Mobile DAC, the ES9219Q which is proven and pretty consistent on its performance particularly on decoding performance and power output. The DAC chip itself is quite efficient as it has a low power that can process up to 32-bit with a two channel stereo output along with its advanced circuitry architecture for improvements of dynamic ranges,frequency filters and sampling modes in tandem with its capable built-in SABRE headphone amplifier.

Like all QUESTYLE products, it still utilises its patented technology which is its vaunted CMA module technology. This one is a type of a SiP module with  functional quad audio amplification engines that eliminates negative signal feedback due to better bandwidth, huge improvement of its dynamic signal processing and ultra-low distortion rating will deliver an excellent clarity, detailed and accurate sound reproduction which has a similar peak performance of a Class A amplifier.

As I mentioned before about some of its newly introduced features, The QUESTYLE M18i also includes some wireless connectivity like bluetooth and microphone. The Bluetooth chip of this device is a 5.4 version provided by Qualcomm which improves its Bluetooth Low Energy technology along with improved reliability and stable connection, more efficient on transmitting high data transfer and better energy management for lower power consumption compared to its previous generation. Since this is a Qualcomm component module, it can support advanced bluetooth codecs like apt-X adaptive, apt-X HD, LE Audio and LDAC aside from standard bluetooth codecs like SBC and AAC. This device also utilises an latest generation of Infineon MEMS microphone that supports HD calls with its AI assisted noise reduction technology and noise filter for better SnR, low distortion and better sensitivity matching for high fidelity voice quality.

Another thing is that this device also has a built-in 500mAh lithium-polymer battery whose performance is very underwhelming that it can only wireless bluetooth playback for over two hours on low gain mode and much lesser on high gain mode.

On its product packaging, it has a simplistic presentation and  still shares similar content layout  with the previous M-series models. Aside from M18i headphone DAC/Amplifier, it also includes a short fabric-sheathed  type-C to type-C cable, USB type-C to type-A adapter and paperwork like user’s manual with different languages and warranty card.

The QUESTYLE M18i is a plug and play peripheral device that can support all known major devices on both hardware and software aspects. On the hardware, it's compatible with all known modern computing devices as long as it has a USB type-C connection that supports USB Audio. Another good thing is that it has an Apple’s MFi certification that it can be used across its well-developed ecosystem with its own software and hardware compatibility.

As for its software side, here is the table of lists on its operating system interoperability.

OPERATING SYSTEM	REQUIRED VERSION	SUPPORTING APPS
ANDROID	At least version 5.0 “Lollipop’	UAPP, HiBY Music App, Onkyo HF, Neutron Player
iPADOS	At least iOS 8.4	Apple Music
iOS	At least iOS 8.4	Apple Music
HARMONY OS	Compatible to all versions	Any music apps that supports USB Audio Access Mode
WINDOWS	At least Windows 10 1083 version	Any music apps that supports USB Audio Access Mode
LINUX	All distros (Linux Mint works well)	Any music apps that supports USB Audio Access Mode

In this review,  I will use my Android phones 9 (Android 9.0 up to the 13) and a laptop with a LINUX MINT OS.

The QUESTYLE M18i can deliver a strong power output that can drive some of power hungry cans and IEMs with special drivers that need better amplification to sound properly. With some of its newer components that if it was paired to some overly sensitive IEMs, there will be no worrying about unwanted noise floor distortions.

List of headphones and IEM earphones that will be used on this test.

• LETSHUOER S12 2024
• LETSHUOER EJ07
• LETSHUOER EJ09
• SIVGA ANSER
• SENDY AIVA 2
• 7TH ACOUSTIC SUPERNOVA

As for its tonal performance, it appears that QUESTYLE M18i delivers a bit of a warmish-neutral sound profile as it has a noticeable more textured compared to the previous M15 models which are known for their balanced-neutral type of sound that makes them more ideal tool on audio reviewing.

LOWS/BASS:

This device conveys a more firmness and tactility on the bass response to sound more  punchy, more denser and impactful that pairing it with IEMs with more emphasis on low frequency will add more dynamic character. It can deliver a deep and reverberating quality on its sub bass presence that were generated from low-tuned string instruments like bass, guitars, double-basses and octobasses, and also on percussives drum machines and synthesisers.

And on its mid bass, apparently that if it was paired to more neutrally-tuned IEM earphones, it somehow adds a bit more texture as it give more body on deep male vocals as it add richness, resonance and sombre sound but not to the point that it sounds too boomy and authoritative. And also on instruments, particularly on bass-clef ones, bass guitars will have more dusky sound, double-basses sounds more broader and resonant, bass trumpets sound fuller with a more darker timbre and a bass kick drums’ strikes will have a bit fuller and sonorous sound.

MIDRANGE:

As it maintains a neutral presentation, I can certainly pinpoint that there is a little bit of warmth as it adds more depth and richness on vocals and instruments to sound organic as possible while maintaining a clean and detailed sound quality on them. On the sound quality of male vocals, baritones have smooth and rich sound while the tenors have that brassy and ringing quality on their voices, and then, a tender and clear falsettos of countertenors. For female vocals, a richer plushy sound on contraltos, a velvety and coppery sound on mezzo-sopranos, and then, a more satiny and creamy sound on soprano vocals.

About instruments, on strings, a bit buttery sound on guitars, a sensuous and silky sound on cellos and a sweet and softer sound on violins. On the woodwinds, it somehow maintains the clear and light sound on piccolos, a graceful yet brilliant sound on concert flutes, a mellow and rich sound on clarinets and a sonorous and reedy sound on saxophones. The brass instruments, in corresponding order, are full, rounded and sound on trumpets, trombones and horns. As for the remaining instrument type, the percussion ones, a harder and precise sound on snares, as sonorous and full sound on every stroke on field drums, a rich and resonating sound on tom-toms, and a deep and substantial sound on kettledrums. And lastly, the pianos seem to have a balanced tone as they have rich, sweet and clear sounds on them.

HIGHS/TREBLE:

The treble quality on this one delivers a lustre and sheen presentation with sufficient amount of airy enough to highlight the clarity and definition on vocal articulation and a sharper attack of both rhythmic and percussive instruments. If it is paired on some IEMs with a neutral-ish bright sound signature, it somehow adds a sufficient amount of air without emphasising too much on the brilliance section on the high frequency region.

This device somehow adds a bit more brilliance, silvery and shimmer on respective treble-clef instruments; cymbals, glockenspiels and celestas.

OVERALL TECHNICALITIES:

Like all M-Series that I have tested in which are remarkable in terms of technical performance, QUESTYLE M18i is no exception as it also shares those impressive qualities that defines these portable headphone amplifiers. It is capable of projecting a fairly spacious sound field dimensions with a well-layered black background soundscape.

It has pretty excellent on resolution capabilities on how it contrast between macro-dynamics and micro-dynamics as the former will have a more concrete dynamic range as it how it highlights the gradual volume phase from soft and quite levels up to the loudest level on instrumental passages and chorale lines, while on the latter, it is able to show some micro-details, nuances and subtleties in a sonic gradient with likes of notational attack of instruments, vocal ends and reverb tails.

PEER COMPARISONS:

QUESTYLE M15/M15i

• It shares similar design language with the M18i but it has a compact size on its rectangular form factor.
• They don't have an OLED Panel to display the current status but on its tempered glass, we can clearly see its internal parts like circuit board, transistors and ICs.
• It uses an LED indicator to determine its current sampling rate.
• Unlike the M18i,  it doesn't have any physical key buttons for volume control and basic media playback control and its toggle switch has a different function as it is used to adjust gain modes.
• It doesn't have a built-in battery, so it doesn't have any bluetooth connectivity at all nor an integration of a HD microphone to receive calls.
• It uses a flagship grade USB DAC chip from ESS, ES9281AC.
• The M15 can process and decode up to 32-bit/384khz on PCM audio and up to DSD256 on DSD format, The M15i is even more capable as it can process up to 768kHz on PCM and up to DSD512 on DSD format.
• It has a dual headphone jack with different output and uses a USB-C as its connector to a host device.
• The M15 has a balance-neutral sound profile with some slight emphasis on high frequency section while the M15i has a tad warmer sound profile.
• It has an excellent technical capability from soundstage size projection up to the pretty resolution on its resolution capabilities although the M15 has a slight edge on micro-dynamics as it has a bit sharper definition on micro-details, grains and nuances.

HIBY W3II

• It has a smaller and slimmer profile compared to the M18i and its frame is made of a high quality PC shell with a built-in shirt clip that makes it lighter.
• It doesn't have any screen but rather a panel with some graffiti designs on it.
• It has an LED indicator for power and bluetooth connection status.
• This device has three button keys for power and volume control, it also works as basic media playback control.
• It has built-in battery with a power capacity of 320mAH but to my surprise, it has longer playback time on both standard Bluetooth formats and advanced Bluetooth codecs as it can play up to 10 hours of continuous playback and a lesser time duration on advanced Bluetooth codec like apt-X HD and LDAC around 7-8 hours.
• It also has a built-in HD microphone like the M18i which also has clear voice quality.
• Aside from its Qualcomm Bluetooth chip, it also has a NFC feature.
• It has a proven Cirrus Logic DAC chip, CS43131 that can process up to 32-bit/192kHz with an output voltage of 1.75Vrms in 98mW of power output.
• It has only one type of headphone jack which is a standard 3.5mm.
• It has a strong software as you can utilise its more functionality via HiBY Blue App.
• It has a warmish-neutral type of sound that makes it a bit closer to analogue profile from the old generation of high fidelity sound.
• It has a pretty decent technical performance from above-average soundstage size, good layering on its soundscape and acceptable resolution capabilities.
• This one is even way cheaper as it was priced around US$40 at the time of its release.

As I conclude this product assessment, The QUESTYLE M18i is definitely a big upgrade from its predecessors as it has some added operationalities that makes it more convenient to use either on a typical plug and play use or in wireless bluetooth transmission mode. For sure that there are some noticeable  issues like its playback duration as I’m quite dissatisfied with its performance as it has a rather short uptime of just over 2 hours along with its longer charging time. Aside from its meagre battery performance, I wish that it has some built-in basic EQ just like devices of similar profile. Nevertheless, I will still recommend this device who is looking for excellent and refined tonality with exceptional technical performance, along with support of more advanced bluetooth codecs and a solid build quality that makes it more premium.

The QUESTYLE M18i is now available on QUESTYLE’s official store and you can see the link that I have provided below.

LINK: https://questyleshop.com/products/questyle-m18i

For more QUESTYLE product reviews:

◼ QUESTYLE M15

◼ QUESTYLE M15i

SPECIFICATIONS:

MODEL: QUESTYLE M18i

MATERIAL: CNC-milled anodised Aluminium Alloy

DAC CHIP: x2 ESS ES9219Q

DECODING CAPABILITY: (PCM) 32-bit 44.1 -384kHz/ (DSD) DSD64-256

BLUETOOTH VERSION: 5.4

BLUETOOTH CHIP: QUALCOMM

BLUETOOTH SUPPORTED CODECS: SBC, AAC, aptX,aptX HD, aptX Adaptive, LE Audio, LDAC

CALL FUNCTIONALITY: Supported via Infineon microphone module

BATTERY CAPACITY: 500mAh

HEADPHONE OUTPUT PORT(S): 3.5mm single-ended, 4.4mm balanced

POWER OUTPUT: 28mW at 300 Ohms (4.4mm balanced output)

FREQUENCY RESPONSE: 0.1dB (20hz-20kHz), 2dB (20kHz-80kHz)

THD: 0.0002%

OVERALL DIMENSIONS: 75mm x 35mm x 14.5mm

PROS:

● A bit larger profile than its predecessors as it has some newly introduced features and latest portable audio technology, but still considered as a compact one.

● Solidly built yet lightweight as it uses an aviation-grade aluminium alloy.

● An OLED screen for the device's status.

● Tactile physical key buttons for volume controls, basic media playback control and gain mode.

● Volume level up to 60 steps with granular degree of adjustments.

● A toggle switch for different device usage as it either powered independently or syphoning off the power source of its host device.

● A small battery inside.

● Additional USB Type-C port for output charging. 

● Finally, a wireless bluetooth feature and even HD microphone support.

● The bluetooth transmission supports some of the advanced bluetooth audio codecs in the market.

● One of the few bluetooth module portable DAC/amps in the market thats supports lossless Snapdragon Sound. 

● It has a warmish-neutral sound profile.

● Tactual bass response .

● Sufficiently warm and ample textured midrange presentation.

● Smooth and inoffensive treble response.

● Excellent technical performance

● Capable of amplifying some of the hard to drive cans out there.

CONS:

● Disappointing battery life.

● No built-in EQ features.

● Can’t switch into low gain mode on bluetooth mode.

● The additional USB type-C port can only be used for a charging only, not on USB sync mode.

● An additional leather case with shirt clip included inside of its packaging box could be better. (it has but it was sold separately)

TESTING TRACKS: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)

Alison Krauss -When You Say Nothing At All *

Jade Wiedlin - Blue Kiss**

Led Zeppelin - When The Levee Breaks **

Mountain - Mississippi Queen *

Queen - Killer Queen **

Guns N' Roses - Patience *'*

Eric Clapton - Tears in Heaven '*'

Sergio Mendes- Never Gonna Let You Go '*'

Pearl Jam - Daughter **

Roselia - Hidamari Rhodonite *

Assassin - Fight (To Stop The Tyranny)*

Celtic Frost- Visual Aggression *

New Order - Blue Monday *

The Corrs- What Can I do (unplugged version) *

Jimi Hendrix Experience - Voodoo Child *

The Madness- Buggy Trousers *

Metallica - Motorbreath **

Mariah Carey- Always Be My Baby *

Destiny's Child - Say My Name *

Malice Mizer- Au Revoir *

Mozart - Lacrimosa *

New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *

Eva Cassidy - Fields of Gold (Sting cover)*

Michael Jackson - Give In To Me *

Exciter - Violence and Force *

Diana Krall - Stop This World **

Debbie Gibson - Foolish Beat *'*

The Sisters of Mercy – Lucretia My Reflection**

Suzanne Vega – Luka **

Lauren Christy – Steep *

Ottoman Mehter - Hucum Marsi *

Diana Damrau - Mozart: Die Zauberflöte*

P.S.

I am not affiliated to QUESTYLE nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.

Once again, I would like to send my gratitude to the Questyle Audio Rep for providing this review unit. I truly appreciate her generosity and trust towards me and other reviewers.