MAS Audio Science X5i Review: Near Perfect Adaptable Audio At A Price

I’m not the resident audio guy here at MobileTechTalk, that would be Mark, but I have tested my fair share of audio devices, so when MAS Audio science hit me up to check out their brand new X5i in earbuds as well as the MAS XX Bluetooth cable, I was excited. Then I saw the price and my jaw dropped, but not before I said yes.

MAS Audio X5i
  • Warm, broad sound.
  • Replaceable cables.
  • Insane quality Bluetooth Audio
  • Ridiculous Battery Life
  • Well built
  • Price?
  • Mo Lightning Cable
  • USB-C cable is late

Buy on Amazon UKMAS Audio Science X5i Review


  • 10mm Dynamic + 4 Balanced Armature drivers
  • 12Ω Impedance
  • Frequency Response – 5-70,000Hz
  • Sensitivity – 105db/mW(@1kHz)


The X5i’s are designed in a way that makes them tick all the technical boxes of luxury, but they don’t seem to have put much thought into how to combine them all. There is leather (or pleather, not sure) and metal, anodized to a pale gold, with nice black plaited cables (not braided, plaited silicone cables) they’re hefty, which leads me to believe some sort of steel over aluminium, but I can’t be sure. They’re very nice to look at but they’re certainly not subtle.

MAS Audio Science X5i Review

They’re also not small. Whilst I originally thought this criticism was just me and having small ears or something, I showed them to a few other people and had them try them on and they all said the same thing, they’re remarkably heavy, and they really stick out far from your head. They get somewhat far into your ear canal, but it is a straight track, no angles or curves, just straight into the ear. Part of the reason it has taken me a while to review these ear buds is that I’m still having trouble with my jaw, which affects the shape of the inner ear. These being so solid, so heavy and having a straight through shape meant that for days or weeks at a time, I physically either couldn’t wear these or couldn’t wear them for longer than 5 minutes.

MAS Audio Science X5i Review

The X5i’s come with 2 cables in the box, the one that is attached is the 3.5mm cable without the microphone or control box, the one with microphone and control box are in a pouch inside the box. The pre-installed cabled is, as I said earlier plaited, and it’s certainly strange to see. It almost seems like they forgot to put the final sleeving on a cable, but I don’t mind this, it’s different, and not worse.

MAS Audio Science X5i Review

The detachable cables are actually “a thing” on the X5i’s though. The main cable as I said terminates in a 3.5mm audio jack and doesn’t have a control box anywhere on the cable. In the box comes with another cable that also terminates in a 3.5mm audio jack, but it does have a control box with a microphone too. Alternatively, you can buy extra cables, currently only the XX Bluetooth cable is on sale (I have it and am reviewing it here as well) and in the future a USB-C cable with control box and mic is coming, though MAS Audio Science told me it won’t be ready for a bit. These cables connect with what appear to be MMCX connectors, so they might be able to have generic cables plugged into them, but I’m not brave enough to potentially break $300 ear buds I didn’t pay for.

Sound Quality

In 2 words? Holy Crap.

In a few more, it is not without some work, but wow, these can sound stunning. Let me start out by saying that although these came with the 3.5mm audio cable attached, and I did spend the first week or so with it, most of my testing has been with the XX Bluetooth cable.

MAS Audio Science X5i Review

With the 3.5mm cable attached, the X5i’s sound really great, neutral, but soulful in a way I wasn’t expecting. They don’t blow out the mids or highs and they don’t try to shake your ears apart with bass, they try to get as close as possible to a neutral soundstage with a slightly elevated midrange that vocals sound great, but instruments also aren’t flat. Bass heads, these aren’t for you, they have bass and it is plenty, but I’m not going to be listening to Bassnectar or Skrillex in these, I’m more likely going to be listening to some Frank Sinatra or Andrea Bocelli.

MAS Audio Science X5i Review

These are of course closed, they aren’t going to have the widest soundstage, but the mix of large Dyanimc drivers and Balanced Armatures mean that, at least for my learning ears, that the depth of what you’re hearing is, for lack of a better term, warmer. For instance, using Andrea Bocelli again, listening to Ave Maria, I feel like I can hear the trembles in his voice, the slight vocal slides, and all I can do is smile. These are acoustically comfortable even if they don’t blow me away with their sheer volume or bass.

MAS Audio Science X5i Review

When testing with the 3.5mm cable, I was mainly using my laptop a Samsung Galaxy Book with its 3.5mm audio jack, or on my PC with my FiiO A1 portable DAC/amp, these sounded great, but these certainly sounded better with the FiiO amp and DAC, but that is, of course, to be expected. But it brings me to my next point.

MAS XX Bluetooth Cable

The Bluetooth audio cable for the X5i’s is a bit of a mystery. I can’t tell you what DAC is inside this cable, nor the amp, nor the battery size, because I just don’t know and I’m not cracking it open to find out, but I can say that these buds with this cable sound freaking awesome, and more importantly, they sounded the same no matter what I was using them on.

MAS Audio Science X5i Review

The 3.5mm audio cable made these sound good on whatever I used on it, but when I had a good DAC and an amp with some power behind it, they sounded better. On the Bluetooth cable, MAS Audio Science has the DAC and amp they want and they know how much power that uses so they out a monstrous battery in this cable to have enough juice to power said headphone amp and the result is the buds sounding the same awesome sound no matter if it was my Huawei P30 Pro, my BlackBerry KEY2, my Galaxy Book or anything else.

MAS Audio Science X5i Review

This is also what makes me excited for the USB-C cable, you get the benefit of the Bluetooth cable (the DAC and amp are in the cable) but they can pull power from the phone! Huzzah!


I charged them the day I got them, and in 6 weeks I think I’m nearly needing to charge them again. Yeah, they’re great.

MAS Audio Science X5i Review

Sadly it’s a MicroUSB charger, and I will complain about this until companies stop putting MicroUSB chargers on devices.


The Ecosystem play here is that you can buy the X5i’s, or the X5h’s (on-ear headphones instead of In-Ear) and the cables you have are interchangeable, and that is awesome.

MAS Audio Science X5i Review

Though I’m not sure how far this can be taken unless they are going to make a Lightning version of the cable as well, what else can they do? A 0.25-inch jack? Who knows.


These are my new favourite Fancy ear buds, and they just so happen to sound best (currently) in their Bluetooth form, so I don’t have to worry about cables when I use them, but they are expensive. The ear buds themselves are $299, and the Bluetooth cable is $99, and the USB-C cable will be an additional $99 if you want it. That isn’t cheap, and I understand that, and there are diminishing returns with audio after a certain point, but these really do sound stunning in my opinion.

MAS Audio Science X5i Review

For the foreseeable future, I’ll be keeping the Bluetooth cable on my X5i’s. Sure I get a really nice sound on my desktop with the FiiO A1, but I’m not always going to be using them on my desktop, and I really like the sound on the Bluetooth cable. Do I recommend these? Hell yeah if you can afford them, and also if they type of music you listen to matches up with this relatively neutral, vocal-focused solution.

I just hope I don’t get addicted to fancy audio now because that is a habit I cannot afford.

About Domenico Lamberti

Technology has been a big part of my life for years, whether it be ripping the family computer apart to see how it worked, playing with the new phones that Dad brought home from work. Senior Reviewer for MTT.

One comment

  1. Tried this one, and really not recommend it. The ear tips get/fall out of my ears easily.

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