64 Audio Duo VS 64 Audio U4S

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

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64 Audio Duo and 64 Audio U4S use 1DD+1BA and 1DD+3BA driver setups respectively. 64 Audio Duo costs $1,200 while 64 Audio U4S costs $1,100. 64 Audio Duo is $100 more expensive. 64 Audio U4S holds a decisive 2.1-point edge in reviewer scores (6.1 vs 8.1). 64 Audio U4S has better mids with a 0.8-point edge, 64 Audio U4S has better dynamics with a 0.7-point edge, 64 Audio U4S has significantly better details with a 2.3-point edge and 64 Audio U4S has significantly better imaging with a 1.5-point edge.

Insights

Metric 64 Audio Duo 64 Audio U4S
Bass 8 8
Mids 7 7.8
Treble 7 6.8
Details 5 7.3
Soundstage 6.1 6
Imaging 6 7.5
Dynamics 7 7.7
Tonality 6.2 7.4
Technicalities 5.5 7
Take these comparisons with a grain of salt—we don't have enough 64 Audio Duo reviews saved yet to provide an unbiased result.

64 Audio Duo Aggregated Review Score

Average Reviewer Scores

Super* Review
Crin
Precogvision
Head-Fi.org

Average Reviewer Score:

6.1

Mixed to Positive

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

Reviews Comparison

64 Audio Duo reviewed by Precogvision

Precogvision 6.4 Reviewer Score
A- Tuning
B Tech
Strong dynamics and easy-going signature that could use more detail in the midrange.

Precogvision original ranking

Precogvision Youtube Channel
Bass: A+ Mids: A- Treble: A- Dynamics: A- Details: C+ Imaging: 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

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64 Audio Duo reviewed by Super* Review

Super* Review 4* * score rescaled + normalized
check links for more info:

Super* Review original ranking

Super* Review Youtube Channel

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 Duo reviewed by Head-Fi.org

Head-Fi.org 8.8 * score rescaled + normalized
3 community members have rated the 64 Audio Duo 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 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

64 Audio Duo (more reviews)

64 Audio Duo reviewed by Crin

Crin 5 Reviewer Score
C+ Tuning
C+ Tech
check links for more info:

Crin original ranking

Crin Youtube Channel

64 Audio U4S (more reviews)

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 Duo User Review Score

Average User Scores

Average User Score: n/a

Based on 0 user reviews

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64 Audio U4S 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 Duo Gaming Score

Gaming Score & Grade

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

Gaming Score

4.7

Gaming Grade

C

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

64 Audio Duo 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-
  • It offers a competent showing, maintaining cohesion on straightforward arrangements. Complex passages start to challenge it, but never derail the show.
Bass A+
It delivers flagship-worthy bass, rich in both rumble and nuance. Reference tracks showcase its grip.
Mids A-
Expect lifelike vocals and instruments with impressive nuance and realism. You can easily follow harmonies and backups.
Treble A-
Treble performance is excellent—airy, extended, and beautifully controlled. It reveals subtle studio ambiance.
Dynamics A-
Dynamic performance is excellent, combining sharp transients with strong contrast. Transients snap with authority.
Details C+
The mix feels articulate, yet the tiniest ripples don't always sparkle. Background ambience is reasonably clear.
Imaging B
Good imaging with precise instrument placement and clear front/back localization. Positions snap into place convincingly.
Gaming C
Minimal environmental definition provides only general audio cues. Suitable for games where positioning isn't critical. Bad value-to-cost for gaming purpose - not recommended

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

64 Audio Duo User Reviews

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64 Audio U4S User Reviews

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