Wired IEMs
Sennheiser IE 900
73Great
$1,580
Full review dataSennheiser IE 900 vs THIEAUDIO Monarch MKIV: which should you buy?
On aggregated review scores the THIEAUDIO Monarch MKIV comes out ahead with a HearWiki score of 84. The full breakdown - sub-scores, specs and what reviewers actually said - is below.
Our pick: THIEAUDIO Monarch MKIV - Outstanding overall at around $1149.
Wired IEMs
THIEAUDIO Monarch MKIV
84Outstanding
$1,150
Full review dataScore breakdown
Each axis is a 0–10 blend of what reviewers scored, not a lab measurement.
THIEAUDIO Monarch MKIV leads on 4 of 4 measures.
- Sennheiser IE 900
- THIEAUDIO Monarch MKIV
HearWiki score
73
84
Sound
8.7
9.4
Value
4.7
7.6
Price (USD)
$1,580
$1,150
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 THIEAUDIO Monarch MKIV is 4 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 4 years between them, that is a thin return - treat this as a restyle rather than a new platform.
- IE 9002021
- Monarch MKIV20254 yr newer
Specifications
IE 900Monarch MKIV
- Type
- Wired IEMs
- Wired IEMs
- Price (USD)
- $1,580
- $1,150
- HearWiki score
- 73
- 84
- Released
- 2021
- 2025
- Availability
- Still sold new
- Sold new
- Driver
- 7 mm dynamic
- 2DD + 6BA + 2EST tribrid
- Driver type
- dynamic
- tribrid
- Driver configuration
- -
- 2DD + 6BA + 2EST
- Driver size
- 7 mm
- 8 mm
- Drivers per side
- 1
- 10
- Frequency response
- 5 Hz - 48 kHz
- -
- Impedance
- 18 Ω
- -
- Sensitivity
- 123 dB/mW
- -
- Bluetooth
- 5.x
- -
- Multipoint pairing
- No
- -
- Wireless charging
- No
- -
- Active noise cancelling
- No
- -
- ANC type
- none
- -
- Transparency mode
- No
- -
- Companion app
- No
- -
- Custom EQ
- No
- -
- Wear detection
- No
- -
- Controls
- none
- -
- Weight
- 4 g
- -
- Water resistance
- none
- -
- Foldable
- No
- -
- Detachable cable
- Yes
- -
- USB-C
- No
- -
- Connector
- MMCX
- -
What reviewers said
Sennheiser IE 900
The Sennheiser IE 900 is a premium single-dynamic-driver IEM that delivers exceptional clarity, detail, and a coherent, natural soundstage for its size. Its lightweight, premium build and precise imaging make it a reference-grade choice, though its high price and lack of features like ANC or wireless support mean it's aimed squarely at wired audiophiles. Overall, it's an impressive technical performer that earns cautious praise rather than an unqualified recommendation at its cost.
- Pro:Outstanding detail retrieval and clarity
- Pro:Coherent, natural timbre from a single dynamic driver
- Pro:Lightweight and premium build quality
- Con:Very high price for a wired-only IEM
- Con:No noise cancellation or wireless features
- Con:Cable noise can be noticeable during use
THIEAUDIO Monarch MKIV
The Monarch MKIV is a flagship in-ear monitor built around a ten-driver tribrid configuration, blending dual 8mm dynamic drivers, six balanced armatures, and two electrostatic tweeters. It offers a studio-neutral sound signature with an additional switchable bass-boost mode for listeners who prefer a more impactful low end.
- Pro:Reference-grade neutral tuning with excellent clarity
- Pro:Versatile bass boost mode adds flexibility
- Pro:Detailed and extended treble from electrostatic tweeters
- Con:High price point limits accessibility
- Con:Requires a capable source to perform at its best
- Con:Large shell may not suit smaller ears
Summaries are AI-condensed and paraphrased from published reviews and specs - not original hands-on testing. More on our method.
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