Fosi Audio IM4 - Reviews & Ratings
3 Reviews (B Tier | 6.3/10)
Summary
Reviewers consider the Fosi Audio IM4 to be a reliable companion that rarely puts a foot wrong, where quality-of-life touches bolster the experience.
Average Reviewer Scores
Average Reviewer Score:
6.3Mixed to Positive
Average User Scores
Average User Score: n/a
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Gaming Score & Grade
- The gaming score is prioritizing technical capabilities of the IEM (Separation, Layering, Soundstage) and good value.
Gaming Score
5.9Gaming Grade
B-Fosi Audio IM4 Details
Driver Configuration: 1DD (10mm beryllium-coated)
Tuning Type: Neutral
Price (Msrp): $99
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Reviews
Reviewed by: Jaytiss
2025-10-16
6.3
Reviewer Score
Youtube Video Summary
Fosi Audio IM4 brings a beryllium-coated single DD in a compact shell with thoughtful venting that behaves almost open-back for comfort during long sessions. Build is surprisingly premium for ~$100: a small, well-finished nozzle that grips tips, a light but durable cable with color-coded channels and a working chin slider, a tidy case, and tuning nozzles (black/gold) plus multiple tips. It’s the kind of fit and finish usually saved for pricier sets.
Tonally, this is an engaging, warm-rich tuning with elevated sub-bass, good texture, and plenty of detail—not a neutral reference. There’s energy in the 2–4 kHz region and a bit of 5–6 kHz bite that can read as “cat-ear” presence, trading strict smoothness for extra soundstage perception and clarity. Versus the many neutral options at this price, IM4 feels more characterful and fun; think closer to sets that use a staged upper-mid/treble contour than to flat targets. Filters/foams or a touch of EQ can gently tame peaks while keeping the lively character.
On the scoreboard: bass 7/10 (clean shelf and punch), mids a touch recessed versus a neutral target, treble lively with agreeable detail, and stage/detail notably good for the class. Overall, a well-built, fun, and slightly audiophile-tuned single-DD that will appeal to listeners who value texture and excitement over strict neutrality—plus rare build quality and extras at this price make it a solid value.
Jaytiss Youtube Channel
Reviewed by: Z-Reviews
2025-10-16
6.2
* score rescaled + normalized
Youtube Video Summary
Quirky name aside, the Fosi Audio IM4 brings a 10 mm beryllium-coated single dynamic driver with a tuning that reads more cohesive, clean, and neutral than bass-bomber. Music floats with a great soundstage and a velvety midrange, giving smooth-jazz and vintage recordings that “swirling around the head” vibe without getting muddy. Hints suggest a price under $100, which would make this one of the stronger performers in the budget bracket, especially given the unexpectedly premium build.
The shells feel like they were machined from the same stuff as Fosi’s amps—weighty, thick, nearly indestructible metal—with a solid 3.5 mm cable (no 4.4 option noted). Accessories are unusually thoughtful: two tuning nozzles (black = lightly damped; brass = no damping) and three styles of tips. Swap to the brass nozzle and treble detail jumps while bass eases off, which can turn the top end a touch spicy for some; stick with the damped setup for a smoother, “just be good” balance. Add a decent case and, if the rumored price sticks, it’s a high-confidence recommendation in the sub-$100 class.
Z-Reviews Youtube Channel
Web Search
2025-10-16
6.5
Reviewer Score
Fosi Audio’s IM4 is an unusual entry-level IEM that uses an open-back shell and a single 10 mm beryllium-coated dynamic driver, aiming for a more natural presentation than typical sealed designs. The open back expands perceived space but also leaks sound and offers little isolation, making it better for quiet environments than commuting . Launch pricing sits at $99, with CNC-machined aluminum shells and a dual-magnet N52 motor backing the diaphragm for control and efficiency .
Sonically, the IM4 targets a balanced/neutral tonality with moderate bass lift and smooth upper mids, yielding an easygoing listen rather than a V-shaped “wow” effect. Stage width is a relative strength for the price—helped by the open-back architecture—while imaging is clean if not class-leading; macrodynamics and microdetail are competent but won’t dethrone closed rivals known for slam. Build and fit are light and ergonomic, and the package includes interchangeable nozzles (aluminum vs. brass) that subtly adjust brightness/sibilance, offering a bit of tuning flexibility without EQ .
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Compare Fosi Audio IM4 to popular alternatives
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JUZEAR x Z Reviews Defiant offers better mids.
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Fosi Audio IM4 vs. Letshuoer DZ4
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Average Technical & Tuning Grades
Average Tunign Grade
B+- The tuning leans easygoing, yet occasional unevenness nudges it away from greatness. A bit of EQ polish can smooth things nicely.
Average Technical Grade
B-- Overall technicalities are acceptable, delivering enough clarity for casual sessions. Imaging is serviceable though not immersive.
User Reviews
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Pros
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Cons
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