Review: Questyle CMA18 Portable

Sound impressions

It’s important to note that devices like CMA18 Portable don’t have a ‘sound’ of their own, since their main function is to decode digital data, convert it into analogue signals, and transmit it through a cable to IEMs and headphones. I know that probably sounds overly simplistic, but it helps when reading the sound impressions to remember that I’m describing the CMA18 Portable’s effect on the sound rather than the sound itself. 

Testing was done using three different IEMs and a set of headphones (see select pairings below) over the past two weeks, noting consistent traits in the sound when compared to other sources (see select comparisons). It’s important to keep this context in mind, in that as much as I’m describing how CMA18 Portable shapes the sound, I’m also describing the changes relative to other sources.     

With that awkward explainer out the way, I’d say that CMA18 Portable is tonally neutral with a dash of density and sweetness that makes it both musical and fatigue-free. 

Breaking down the sound profile into digestible descriptors based on my listening notes:

  • Bass is tight, controlled and punchy, with a weighty presentation that doesn’t impact the speed and incisiveness of an IEM’s bass delivery, while enhancing its ability to convey texture. 
  • Midrange notes sound fuller, vocals given a slight polish without masking or veiling details, adding to their sweetness, and instruments given space to play without sounding strident or smearing. 
  • Treble is ever so gently rounded, but still manages to deliver maximum extension, sparkle and detail, and as such won’t be fatiguing unless your IEM is stubbornly tuned to fatigue. 

Diving deeper, this is not a ‘flat’ neutral, as I do hear a touch of emphasis down low that supports, rather than elevates, a solid, meaty sub-bass response that extends well into the lowest registers. There’s also some notable sparkle up top, although again I’m not noting any significant elevation to the treble frequencies. 

If anything is emphasised here, it’s possibly the midrange – and specifically vocals – which appear to be pushed forward ever so slightly. Still, I don’t think this is a case of a midrange emphasis – I definitely don’t hear any upper midrange boost over and above what the IEMs I’m familiar are tuned with – so it’s more likely that the excellent separation of vocals and instruments contributes most to what I’m hearing (more on this below).

Using some track examples to illustrate my points, Madi Diaz’s organic vocals in Same Risk, feel denser but also sweeter, her trailing breath smoother and less glassy. This added note weight is consistent between tracks and transducers, so it’s fair to say one of the most notable qualities of the sound is a fuller note weight. 

What’s interesting to me is that this added weight doesn’t come at the cost of clarity; I’m hearing just as much microdetail from each individual ‘ball’ in Yosi Horikawa’s iconic Bubbles, for example, as I do with sources that are thinner and brighter. 

Speaking of Bubbles, this is the track that almost instantly revealed how spacious and holographic the stage is rendered, especially with IEMs and headphones that lend themselves to spaciousness. It’s not that CMA18 Portable casts a massive stage out of nothing, but rather it presents such a high degree of separation and imaging that it’s almost impossible not to notice the added space between, behind and in front of instruments and vocals.

Yes, you’ll notice I’ve segwayed into technical performance. That’s because, to me, it’s the technical performance that makes CMA18 Portable’s tonal presentation so agreeable. 

This is exemplified by what I hear as a virtually noise-free background, darker still than my already-noiseless TOTL DAPs. Combined with the muscular current mode amplifier’s precise control over the drivers, ultra-low distortion and speed, it delivers an exceptionally tight sound with inch-perfect spatial cues that avoids smearing even in the busiest of passages.

Take Whitehorse’s drawling Dear Irony, for instance, with its hard-panned guitar intro in the left channel, followed by the simultaneous overlay of Melissa McClelland and Luke Doucet’s vocals offset only marginally from each other. Many IEMs (and sources) struggle to separate the male and female leads (Luke positioned slightly behind and to the left of Melissa), but whether it’s through tighter control of the guitars and rumbling drums, or a combination of better control and a darker background, separation and layering here is excellent. 

On some electronic tracks, such as Ilan Bluestone’s Will We Remain, the beat effects literally start and stop on a dime, while on others, such as Beyries’ Alone, vocal echoes are free to decay into a seemingly infinite background. At all times, CMA18 Portable manages to keep a tight rein on the presentation, no matter how complex it becomes. The crescendo to Daft Punk’s Contact, for example, can descend into a hot mess with the wrong gear, but adding CMA18 Portable to the chain almost guarantees you a smear-free experience. 

Indeed, that I noticed these nuances across multiple tracks when switching from a different source using the same IEM suggests it’s CMA18 Portable doing the heavy lifting here.

With all that said, I’d be remiss not to mention that some of my peers and fellow reviewers report that CMA18 Portable has some noise bleed or hiss with very sensitive IEMs. I personally haven’t been able to replicate this with my own IEMs, headphones or – to be frank – hearing. Even with my most ‘sensitive’ IEMs, 64Audio’s N8 and Campfire Audio’s Trifecta, there’s no ‘amp noise’ that I can hear during quieter passages.

As such, I’d encourage you to use my notes only as a guide, and always listen for yourself to make an informed decision based on your own music, preferences and hearing ability. 

Continue to select pairings…    



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


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