The MS18 are one of the better-sounding earphones made by Headroom. Although the bass is still generally boomy, it's not as severe as with many previous in-ear models by the brand. This time, however, Headroom successfully implemented a true open-back design, similar to that found on MS16, which actually resulted in open and airy mids and highs, along with a powerful bass response. The cable is a bit on the cheap side, quite similar to the cable found on some of Xiaomi's cheaper models, but probably even better, thanks to the added thickness and the metal parts, and especially the spring that serves as a strain relief. All in all, these earphones actually worth the tiny price they cost and they are one of my favorite earphones in the up-to-$10 price segment.
My main concern with these earphones, and with Headroom products in general, is the inconsistent and untrustworthy quality control that results in channel imbalances across their products.
Pros
After a short getting-used-to, the mids and highs are surprisingly vivid and airy.
A very powerful bass response, with a great sub-bass extension.
True open-back earphones, no gimmicks.
Very comfortable to wear for prolonged listening sessions.
Cons
Boomy mid-bass. The lower-mids get bloated sometimes.
Since these are open-back, there is some sound leakage from the back.
Cheap rubbery cable and the wires seem to be loose inside it.
Very unreliable quality control. Got two pairs, and the driver matching is still not great.
Package & Accessories
Package:
Hard plastic + soft paperboard
Ear Tips - Single-Flange:
S+M+L, grey (translucent), ø4.5mm red bores
Build & Materials
Housings:
Metal + plastic (glossy), open-back, ø5.5mm nozzles, soft strain reliefs
The volume buttons work on Android devices. I don't have an iPhone for compatibility check.
Comfort & Fit
Using the angled shape of the housings and extremely lightweight materials, Headroom has made them very comfortable and easy to wear. I had no comfort issues whatsoever and could wear these earphones for many hours straight.
Lows / Bass
Punchy, impactful and fun-sounding, although a bit exaggerated and boomy. People who dislike bassy earphones should stay away, but those who can appreciate some extra beef in their bass, should consider giving these a try. Quite powerful sub-bass rumble.
Mids / Vocals
Although tonally a bit odd, the mids are very listenable and are quite extraordinarily detailed, considering the price. Unlike many previous Headroom earphones, these don't suffer from recessed mids. The mids are in-line with the crisp treble and instruments are nicely separated, but these frequenceis tend to be slightly overwhelmed by the super-potent bass rumble.
Highs / Treble
Probably the best treble I've heard so far coming from in-ears by Headroom. They truly improved both the loudness and the quality of the highs, offering more detail, sparkle and tonal accuracy. Well done, Headroom.