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Campfire Audio Astrolith - Dual Planar IEM vs Sony IER-M9: which should you buy?

On aggregated review scores the Campfire Audio Astrolith - Dual Planar IEM comes out ahead with a HearWiki score of 81. The full breakdown - sub-scores, specs and what reviewers actually said - is below.

Our pick: Campfire Audio Astrolith - Dual Planar IEM - Great overall at around $2199.

Score breakdown

Each axis is a 0–10 blend of what reviewers scored, not a lab measurement.

Sony IER-M9 leads on 2 of 4 measures.

  • Campfire Audio Astrolith - Dual Planar IEM
  • Sony IER-M9
HearWiki score
81
78
Sound
9.0
9.0
Value
6.5
7.0
Price (USD)
$2,200
$1,500

Generation & platform

The scores rank quality. This is the other question: is the newer one actually newer technology, or the same platform in a new shell?

Same generation

The Campfire Audio Astrolith - Dual Planar IEM is 6 years newer, but it is the same generation of hardware: nothing in the radio, the codecs or the noise cancelling separates them. Nothing separates them on convenience features either, so the choice comes down to tuning and price. For 6 years between them, that is a thin return - treat this as a restyle rather than a new platform.

  • Astrolith - Dual Planar IEM20246 yr newer
  • IER-M92018

Specifications

Astrolith - Dual Planar IEMIER-M9
Type
Wired IEMs
Wired IEMs
Price (USD)
$2,200
$1,500
HearWiki score
81
78
Released
2024
2018
Availability
Discontinued
Discontinued
Driver
2× 14.2 mm planar magnetic
5BA
Driver type
planar
balanced-armature
Driver configuration
-
5BA
Driver size
14.2 mm
-
Drivers per side
2
5
Frequency response
5 Hz - 25 kHz
-
Impedance
8.2 Ω
20 Ω
Sensitivity
94 dB/mW
103 dB/mW
Active noise cancelling
No
-
Voice assistant
No
-
Weight
-
11 g
Detachable cable
Yes
Yes
Connector
4.4 mm balanced
-

What reviewers said

Campfire Audio Astrolith - Dual Planar IEM

The Campfire Audio Astrolith is a premium dual-planar IEM that delivers a fast, clear, and highly detailed sound with impressive staging and technical precision. Its nearly flat impedance and very low distortion make it a strong performer, though it benefits from quality sources and has a couple of minor ergonomic quirks. Overall, it's a notable step forward in the brand's planar lineup, offering a cohesive and resolving listen for those seeking top-tier wired performance.

  • Pro:Exceptional speed and clarity across the frequency range
  • Pro:Very low distortion and flat impedance for consistent performance
  • Pro:Wide, well-defined soundstage with precise imaging
  • Con:Slight mid-bass bloom can color certain tracks
  • Con:Stock ear tips are not very good and may need replacement
  • Con:Best results require a high-quality source or amplifier

Sony IER-M9

The Sony IER-M9 is a premium five-driver balanced-armature in-ear monitor that delivers a refined, reference-grade sound with a warm and coherent character. It offers strong technical performance, detailed midrange, and versatile tuning that suits both critical listening and everyday enjoyment, making it a benchmark in its price range. Its lightweight build and detachable cable add to its appeal as a polished all-rounder.

  • Pro:Detailed and resolving sound
  • Pro:Warm, coherent, and mature tuning
  • Pro:Lightweight and comfortable fit
  • Con:No noise cancellation
  • Con:High price point
  • Con:May lack aggressive excitement for some listeners

Summaries are AI-condensed and paraphrased from published reviews and specs - not original hands-on testing. More on our method.

Compare something else

Swap either side out, or start again from the picker.

New comparisonCampfire Audio Astrolith - Dual Planar IEMSony IER-M9