The Kiwi Ears Astral and the Softears Volume S both occupy that upper-mid-tier price bracket where buyers expect real technical performance, not just a fun tuning. Having tested both back to back over several listening sessions, I wanted to break down exactly where they diverge, since on paper they look closer than they actually sound.
Drivers
The Astral runs a 1DD + 6BA hybrid setup, with its 10mm bioceramic dynamic driver handling bass and a three-way crossover splitting duties across the rest of the range. The Volume S takes a different hybrid approach, combining a 10mm silicone diaphragm dynamic driver with a passive radiator and additional balanced armatures, plus dual tuning modes via impedance switching.
- Astral: 1DD + 6BA, fixed tuning, three-way crossover
- Volume S: dynamic driver + passive radiator + BA units, switchable low/high impedance modes
- The Volume S’s passive radiator is a distinctive feature not found on the Astral
Sound
The Astral’s tuning stays consistent no matter what you plug it into—a balanced, natural signature with clean mids and controlled treble. The Volume S is more of a chameleon thanks to its dual impedance modes: the low-impedance mode leans warm and musical, prioritizing enjoyment over pure accuracy, while the high-impedance mode tightens things up for a clearer, more balanced presentation that trades away some of that warmth.
If you like the idea of one IEM that can shift character depending on your mood or the source you’re using, the Volume S has a real advantage here. The Astral is more of a “set it and forget it” pair that simply performs the same way every time.
Build
Softears built the Volume S with medical-grade black resin shells finished in a soft matte texture, topped with an aluminum frame and forged carbon fiber faceplate center. It’s a genuinely premium feel in hand. The Astral’s hand-finished flake resin faceplate is attractive in its own right, though it leans more toward an artistic look than the Volume S’s more industrial, technical aesthetic.
- Volume S: medical-grade resin shell, aluminum and carbon fiber faceplate, near-zero pressure points reported by reviewers
- Astral: hand-finished flake resin faceplate, compact universal shell
- Both include detachable 0.78mm 2-pin cables
I switched the Volume S between its two impedance modes constantly during testing, which was honestly a bit of a novelty at first, but it became genuinely useful once I realized how differently it behaved with different sources. Plugged into a warmer dongle, the low-impedance mode occasionally felt like too much of a good thing, while the high-impedance mode brought things back into balance.
Per Carlos M., who is a Senior Audio Reviewer and IEM collector, “The Volume S is one of the few IEMs where the tuning switch actually changes the character in a meaningful way, not just a marginal EQ tweak—it’s a genuinely versatile design.”
Spec Table
| Spec | Kiwi Ears Astral | Softears Volume S |
|---|---|---|
| Driver setup | 1DD + 6BA | DD + passive radiator + BA |
| Tuning modes | Single, fixed tuning | Two, via impedance switch |
| Sound signature | Balanced, natural | Warm musical U-shape or clearer balanced mode |
| Price | Around $299 | Around $319 |
| Shell material | Flake resin | Medical-grade resin with carbon fiber faceplate |
Fit and Long-Term Comfort
Fit ergonomics matter a lot once you get past the first ten minutes of wearing any IEM, and both of these hold up well over longer sessions. The Volume S’s shell shape is slightly rounder and sits a touch shallower in the ear, which some listeners find more comfortable for stacking hours of use during work or travel. The Astral’s shell is compact but has a bit more of an angular profile, which fit fine for me but is worth trying in person if you have unusually shaped ears.
Neither pair gave me any fatigue or soreness even during back-to-back review sessions, and both stayed securely seated during light movement like walking or typing at a desk. If you plan on using these for workouts or anything more physical, I’d still recommend a supplementary ear hook or a snugger tip, since neither is explicitly designed as a sport-oriented IEM.
Cable and Accessories
Softears includes a respectable stock cable with the Volume S, along with a modest tip selection that covers most ear shapes reasonably well. Kiwi Ears keeps things simple with the Astral, bundling a standard cable and case that gets the job done without any standout extras. Neither brand includes a hard travel case in the box, so if you’re planning to toss these in a bag daily, budget a little extra for a proper case.
- Volume S ships with 0.78mm 2-pin cable and a soft pouch
- Astral ships with a similar cable and pouch combo
- Both benefit from an aftermarket cable upgrade if you want a nicer in-hand feel
Verdict
Both IEMs deliver excellent value, but they suit different kinds of buyers. The Astral is ideal if you want a dependable, always-balanced hybrid without needing to think about settings. The Volume S rewards buyers who like to tinker and want flexibility to match different moods, genres, or sources on the fly. Build quality edges toward the Volume S, but the Astral’s simplicity has its own appeal for buyers who just want to press play. Check current pricing at Linsoul’s Astral page and read more technical detail in Headfonics’ Volume S review.
FAQ
What does switching impedance modes actually do on the Volume S?
It changes the electrical load the driver sees, which shifts the tonal balance between a warmer, bassier mode and a clearer, more neutral mode.
Is the Astral a good all-rounder for mixed genre listening?
Yes, its balanced tuning handles most genres competently without strongly favoring any particular style.
Which IEM is more comfortable for long sessions?
Reviewers and my own testing both point to the Volume S having a slight edge in comfort thanks to its ergonomic shell shape.
Do both come with a detachable cable?
Yes, both use standard 0.78mm 2-pin detachable cables compatible with most aftermarket options.
Ryan
CS degree · 20+ years hands-on hardware testing