64 Audio U4S VS Fir Audio VxV

IEM Comparison: Expert & Community Scores Side-by-Side

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64 Audio U4S and Fir Audio VxV are in-ear monitors. 64 Audio U4S costs $1,100 while Fir Audio VxV costs $999. 64 Audio U4S is $101 more expensive. 64 Audio U4S holds a clear 0.9-point edge in reviewer scores (8.1 vs 7.2). 64 Audio U4S has significantly better bass with a 2.5-point edge, 64 Audio U4S has significantly better mids with a 1.8-point edge, 64 Audio U4S has significantly better treble with a 1.8-point edge, 64 Audio U4S has better details with a 0.8-point edge and 64 Audio U4S has significantly better imaging with a 1-point edge.

Insights

Metric 64 Audio U4S Fir Audio VxV
Bass 8 5.5
Mids 7.8 6
Treble 6.8 5
Details 7.3 6.5
Soundstage 6 6
Imaging 7.5 6.5
Dynamics 7.7 7.2
Tonality 7.4 5.5
Technicalities 7 6.3
Take these comparisons with a grain of salt—we don't have enough Fir Audio VxV reviews saved yet to provide an unbiased result.

64 Audio U4S Aggregated Review Score

Average Reviewer Scores

Smirk Audio Jaytiss Precogvision
Audionotions Head-Fi.org
Super* Review

Average Reviewer Score:

8.1

Very Positive

Fir Audio VxV Aggregated Review Score

Average Reviewer Scores

Shuwa-T
Head-Fi.org

Average Reviewer Score:

7.2

Generally Favorable

Reviews Comparison

64 Audio U4S reviewed by Head-Fi.org

Head-Fi.org 8 * score rescaled + normalized
4 community members have rated the 64 Audio U4s at an average of 4.3/5 on Head-Fi. Overall sentiment: Excellent.

URL to full Review

Head-Fi.org original ranking

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Fir Audio VxV reviewed by Head-Fi.org

Head-Fi.org 8.5 * score rescaled + normalized
15 community members have rated the FiR Audio VxV at an average of 4.7/5 on Head-Fi. Overall sentiment: Exceptional.

URL to full Review

Head-Fi.org original ranking

64 Audio U4S (more reviews)

64 Audio U4S reviewed by Super* Review

Super* Review 9* * score rescaled + normalized
YouTube video thumbnail
Youtube Video Summary

The 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.

Super* Review original ranking

Super* Review Youtube Channel

64 Audio U4S reviewed by Audionotions

Audionotions 8.5 Reviewer Score
A step down in techs from U12T (possibly a half step down from U6T). But very well tuned and adds in a dynamic driver punch. Timbre is slightly improved compared to U12T due to the increase in midbass and upper mids energy. On the second hand market, 64Audio IEMs are among the best values in portable audio, the U4S is no exception.

Audionotions original ranking

Website (Audionotions)

64 Audio U4S reviewed by Smirk Audio

Smirk Audio 7.8 Reviewer Score
A Tuning
A Tech
A tastefully colored U12t with a more intimate soundstage, a cutback in technicalities, and more bass realism.

Smirk Audio original ranking

Smirk Audio Head-Fi Profile

Bass: A+ Mids: A Treble: A Dynamics: A+ Details: A Imaging: A+

64 Audio U4S reviewed by Jaytiss

Jaytiss 7.8 Reviewer Score
B+ Tuning
B Tech
It's a solid set, with great build quality, but sonically isn't the specialist that I want it to be.

Jaytiss original ranking

Jaytiss Youtube Channel
Mids: A+ Treble: B Dynamics: A- Soundstage: B

64 Audio U4S reviewed by Precogvision

Precogvision 7.7 Reviewer Score
A Tuning
A- Tech
YouTube video thumbnail
Fantastic colored tonality with options, and the unique technical qualities to back it up. M12/M15 modules recommended.
Youtube Video Summary

The 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.

Bass: A+ Mids: A+ Treble: A- Dynamics: A+ Details: A- Imaging: A-

Precogvision original ranking

Precogvision Youtube Channel

Fir Audio VxV (more reviews)

Fir Audio VxV reviewed by Shuwa-T

Shuwa-T 5.9 Reviewer Score
B- Tuning
B Tech
Comment: Rabbit cute I guess. Mild V-shape tuning, with decent technical performance Sounds too generic, note weight isn't well defined

Shuwa-T original ranking

Shuwa-T Website

Bass: B- Mids: B Treble: C+ Soundstage: B Details: B+ Imaging: B+

64 Audio U4S User Review Score

Average User Scores

Average User Score: n/a

Based on 0 user reviews

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Fir Audio VxV User Review Score

Average User Scores

Average User Score: n/a

Based on 0 user reviews

No user reviews yet. Be the first one who writes a review!

64 Audio U4S Gaming Score

Gaming Score & Grade

  • The gaming score is prioritizing technical capabilities of the IEM (Separation, Layering, Soundstage) and good value.

Gaming Score

6.1

Gaming Grade

B

Fir Audio VxV Gaming Score

Gaming Score & Grade

  • The gaming score is prioritizing technical capabilities of the IEM (Separation, Layering, Soundstage) and good value.

Gaming Score

5.1

Gaming Grade

C+

64 Audio U4S Scorings

Average Technical & Tuning Grades

Average Tunign Grade

A-
  • A smooth, agreeable balance keeps the presentation engaging without obvious flaws. Only sensitive ears will nitpick the bumps.

Average Technical Grade

A-
  • Technical chops are reliable, pairing tidy separation with a soundstage that stays conservative. Micro-detail is decent, though never spotlighted.
Bass A+
Expect a gripping low-end presence that marries clarity with visceral impact. Dynamic swings land with thrilling force.
Mids A
Midrange performance is excellent, with natural timbre and great detail. Vocals feel lifelike and full-bodied.
Treble B+
Expect crisp, well-balanced treble that keeps shimmer intact. You hear reverbs decay naturally.
Dynamics A
You get outstanding dynamic agility, from subtle nuances to big hits. Impact comes with quick recovery.
Soundstage B
Good soundstage with proper width and depth, placing instruments in clearly defined positions. Instruments sit in their own lanes.
Details A-
Resolution feels both high and relaxed, capturing nuance with ease. There's zero smearing even at high volume.
Imaging A
Depth mapping feels natural and accurate, supporting convincing immersion. Depth mapping feels precise and natural.
Gaming B
Decent spatial awareness for fundamental positioning. Creates satisfying atmosphere in story-driven games while handling basic directional cues. Bad value-to-cost for gaming purpose - not recommended

Fir Audio VxV Scorings

Average Technical & Tuning Grades

Average Tunign Grade

B-
  • A mostly enjoyable signature keeps things listenable despite a handful of quirks. It handles most playlists without major complaints.

Average Technical Grade

B
  • Technical ability is serviceable, keeping basic detail intact across simpler tracks. It keeps up with acoustic tracks without much fuss.
Bass B-
Expect a balanced but ordinary low end that avoids both extremes. Slam remains moderate and controlled.
Mids B
Midrange presence is good, delivering clear vocals and solid texture. Voices come through with pleasing clarity.
Treble C+
The top end is tidy and serviceable, adding air without overdoing it. Extension is decent for casual listening.
Soundstage B
Lateral spread stretches comfortably while front/back cues start to feel convincing. You can trace front-to-back movement.
Details B+
Nuance retrieval becomes reliable, highlighting expressive touches in every instrument. It rewards attentive listening.
Imaging B+
Good imaging with precise instrument placement and clear front/back localization. Positions snap into place convincingly.
Gaming C+
Fundamental left/right positioning with limited depth perception. Works for non-competitive gaming but lacks precision. Bad value-to-cost for gaming purpose - not recommended

64 Audio U4S User Reviews

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Fir Audio VxV User Reviews

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