EarAcoustic Audio is a budget friendly audio brand founded in 2024 in Shenzhen, China by the makers of TFZ and SUPERTFZ. The company focuses on clear and accurate sound with solid build quality. Its main products are the SPA “Silver Angel” in-ear monitors and the STA series.

In this review, I’ll take a look at EarAcoustic Audio STA-K, provided by KEEPHIFI

The STA-K is a easy to drive dual dynamic driver config. It carries a 10mm beryllium-coated and 6mm PET Dynamic Driver

What’s in the Box
– A lightweight cable
– 3 pairs of silicone eartips
– Two nice transparant shells

My test equipment:
– Shanling M8T
– Shanling UA6
– Campfire Relay dac

Tested Tracks:
Ibrahim Ferrer – La música Cubana
Eric Bibb – Shingle by Shingle
Michael Buble – Me and Mrs Jones
Enigma – Callas went Away
Mark Knopfler – Two Pair of Hands
Melody Gardot – Our Love is Easy

General sound impressions
The STA-K is quite (unexpected) focussed on mid-bass, adding warmth and body, but not in a muddy or overdone way. Although quite musical, It could use a little more oomph in the low end. The treble strikes a pleasant balance, smooth and easy on the ears. It is subtle and not immediately striking, but it rewards you with fatigue-free sessions and a laid-back musical charm. This might not cater to die-hard treble-heads.

Treble
The treble is clear enough to reveal detail and always easy on the ears. There’s no harshness, no sibilance and certainly no piercing moments. While sparkle and air aren’t front and center, they’re present just enough to balance out the warmth. For most listeners, it might hits a sweet spot: refined, controlled and non-fatiguing.

Mids
The midrange stays impressively clean. Just enough weight to make instruments sound full, but without bleeding into muddiness. Detail retrieval is solid and instrument separation holds up well in dense mixes. Male voices sound grounded and warm but not on all occasions. Female vocals like Melody Gardot’ lack depth or emotional presence. It’s not the most expressive midrange.

Bass
The STA-K leans into its mid-bass, giving the low end a warm rich character that feels both textured and musical. The punch is firm and snappy, never sluggish or muddy. As for the sub-bass? It plays more of a supportive role. It’s present and well-behaved, rolling in with just enough depth to round things out, without trying to steal the spotlight. 

Soundstage
The stage isn’t vast or theatrical, but it’s convincingly layered. You get a real sense of front-to-back depth, which helps music feel more immersive. The mid-bass presence adds a bit of live concert energy, giving everything a sense of presence. It won’t transport you into another universe, but it’s more than enough to pull you into the moment.

Conclusion
The STA-K doesn’t aim to be a detail monster or a sterile reference set. Instead, it embraces warmth and musicality, delivering a sound that grows on you the more you listen. It may not suit aggressive genres, but for most genres it sounds pleasant.

When you consider the STA-K is a budget friendly IEM, you’ll find it is a surprisingly capable and enjoyable performer.

Pros

• Nice looking shells

• Ergonomic and comfortable fit

• Bass is punchy and satisfying

• Impressive air and clarity in the upper range for its price range

Cons

• Tonality may not suit every listener

• Upper mids can sound slightly uneven at times

• Some vocals are missing warmth