Sony IER-M9 VS 64 Audio U4S

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

Home Ranking Compare IEMs

Sony IER-M9 and 64 Audio U4S use 5BA and 1DD+3BA driver setups respectively. Sony IER-M9 costs $1,000 while 64 Audio U4S costs $1,100. 64 Audio U4S is $100 more expensive. 64 Audio U4S holds a clear 0.8-point edge in reviewer scores (7.4 vs 8.1). Sony IER-M9 carries a user score of 7.5. 64 Audio U4S has better bass with a 0.5-point edge, Sony IER-M9 has better treble with a 0.7-point edge, 64 Audio U4S has significantly better dynamics with a 2.7-point edge, Sony IER-M9 has better details with a 0.8-point edge and 64 Audio U4S has better imaging with a 0.5-point edge.

Insights

Metric Sony IER-M9 64 Audio U4S
Bass 7.5 8
Mids 8 7.8
Treble 7.5 6.8
Details 8 7.3
Soundstage 7.4 6
Imaging 7 7.5
Dynamics 5 7.7
Tonality 7.5 7.4
Technicalities 7.6 7

Sony IER-M9 Aggregated Review Score

Average Reviewer Scores

Audionotions Precogvision Tim Tuned Crin
Yifang

Average Reviewer Score:

7.4

Generally Favorable

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

Sony IER-M9 reviewed by Audionotions

Audionotions 7.5 Reviewer Score
Nice note weight, very balanced, shockingly good at imaging held back by finicky fit and vacuum seal - fit issues can be resolved by changing tips though (for me the stock silicone LL tips eliminated fit issues for me but YMMV). At used prices today, it's a steal.

Audionotions original ranking

Website (Audionotions)

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)

Buy 64 Audio U4S on audio46

Ad
Using this affiliate link for ordering your 64 Audio U4S or any other IEM helps fund our free service at no extra cost to you.

Price: $1,122

Buy 64 Audio U4S on audio46

Sony IER-M9 reviewed by Precogvision

Precogvision 7.4 Reviewer Score
A- Tuning
B+ Tech
Boring, but you won't find anything more well-rounded for the price. Exceptional timbre for a BA IEM.

Precogvision original ranking

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

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

Sony IER-M9 (more reviews)

Sony IER-M9 reviewed by Yifang

Yifang 8 Reviewer Score
S- Tuning
A+ Tech
check links for more info:

Yifang original ranking

Yifang Youtube Channel

Sony IER-M9 reviewed by Tim Tuned

Tim Tuned 7 Reviewer Score
A- Tuning
A+ Tech
Just great accross the board, nothing to fault Not very special

Tim Tuned original ranking

Tim Tuned Youtube Channel
Bass: A+ Mids: A+ Treble: A+

Sony IER-M9 reviewed by Crin

Crin 7 Reviewer Score
A- Tuning
A Tech
Neutral tonality, highly coherent and decent detail pickup. The all-rounder of the IER lineup.

Crin original ranking

Crin Youtube Channel

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 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 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

Sony IER-M9 User Review Score

Average User Scores

Average User Score:

Based on 1 user reviews

7.5

Strongly Favorable

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!

Sony IER-M9 Gaming Score

Gaming Score & Grade

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

Gaming Score

6.5

Gaming Grade

B+

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

Sony IER-M9 Scorings

Average Technical & Tuning Grades

Average Tunign Grade

A
  • Expect an inviting tonal blend that adapts well to genres while staying largely composed. It strikes a nice blend of warmth and clarity.

Average Technical Grade

A
  • Technical performance is solid, offering clear separation and consistent detail retrieval. There's enough space for instruments to breathe.
Bass A
It serves up confident rumble and texture while keeping the spectrum balanced. You can enjoy bass-heavy music without fatigue.
Mids A+
The midrange sounds refined and revealing, balancing clarity with emotional weight. Timbre accuracy rivals studio monitors.
Treble A
The treble is exquisitely tuned, combining crystal detail with relaxed delivery. Micro-details emerge effortlessly.
Dynamics C+
Expect solid impact overall, even if finer gradations feel a touch smoothed. Micro-details could still be sharper.
Details A+
No subtlety is too small; the presentation exposes it all with composure. Complex tracks remain crystal clear.
Imaging A-
Spatial cues respond immediately, reflecting every movement in the mix. Spatial cues respond instantly to the mix.
Gaming B+
Respectable environmental presentation favors atmosphere over precision. Detects obvious directional cues while conveying game world ambiance. 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

Sony IER-M9 User Reviews

Share your experience and build your personal ranking list.

You need to be signed in to write your own review
M Makavelian
7.5

Worth it at used prices for neutral warm all rounder.

Pros
Great all rounder tuning, imaging, comfort.
Cons
Bit lacking in engagement, bass typical of BA drivers.

64 Audio U4S User Reviews

Example User Posted on ...
0.0

"This is an example review"

Pros
  • Example pro 1
  • Example pro 2
Cons
  • Example con 1
  • Example con 2
No User-Reviews Yet

Share your experience and build your personal ranking list.

You need to be signed in to write your own review

Find your next IEM:

IEM Finder Quiz

new
Use this quiz and answer a few questions to get your individual IEM recommendation list
(1/3) How much are you willing to spend on the IEM?
(2/3) Which sound characteristics are particularly important to you?
(3/3) Which tuning do you prefer?
You can select multiple options.
Buy

Footer