FiiO FH9 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

Score breakdown

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

THIEAUDIO Monarch MKIV leads on 3 of 4 measures.

FiiO FH9
THIEAUDIO Monarch MKIV

HearWiki score

Sound

8.0

9.4

Value

4.3

7.6

Price (USD)

$760

$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.

FH92021
Monarch MKIV20254 yr newer

Specifications

FH9Monarch MKIV

Type: Wired IEMs; Wired IEMs
Price (USD): $760; $1,150
HearWiki score: 67; 84
Released: 2021; 2025
Availability: Still sold new; Sold new
Driver: 1DD + 6BA hybrid; 2DD + 6BA + 2EST tribrid
Driver type: hybrid; tribrid
Driver configuration: 1DD + 6BA; 2DD + 6BA + 2EST
Driver size: 13.6 mm; 8 mm
Drivers per side: 7; 10
Frequency response: 10 Hz - 40 kHz; -
Impedance: 18 Ω; -
Sensitivity: 108 dB/mW; -
Active noise cancelling: No; -
Weight: 12.8 g; -
Detachable cable: Yes; -
Connector: MMCX; -

Specification comparison of FiiO FH9 vs THIEAUDIO Monarch MKIV
Spec	FiiO FH9	THIEAUDIO Monarch MKIV
Type	Wired IEMs	Wired IEMs
Price (USD)	$760	$1,150
HearWiki score	67 / 100 Good	84 / 100 Outstanding
Released	2021	2025
Audio
Driver	1DD + 6BA hybrid	2DD + 6BA + 2EST tribrid
Driver type	hybrid	tribrid
Driver configuration	1DD + 6BA	2DD + 6BA + 2EST
Driver size	13.6 mm	8 mm
Drivers per side	7	10
Frequency response	10 Hz - 40 kHz	-
Impedance	18 Ω	-
Sensitivity	108 dB/mW	-
Features
Active noise cancelling	No	-
Design
Weight	12.8 g	-
Detachable cable	Yes	-
Connector	MMCX	-

What reviewers said

FiiO FH9

The FiiO FH9 is a flagship hybrid in-ear monitor that pairs a 13.6mm dynamic driver with six balanced armatures for a lively, energetic sound. It delivers a wide soundstage, punchy bass, and crisp treble, while its mild warmth and high sensitivity make it easy to drive from a variety of sources. With a detachable MMCX cable and polished tuning, it stands as a strong contender in its price class.

Pro:Energetic, forward tuning with strong bass and treble
Pro:Wide, immersive soundstage for a hybrid IEM
Pro:High sensitivity and low impedance, easy to drive

Con:No active noise cancellation, wired-only design
Con:Bass may overpower for those preferring neutral signatures
Con:Large shell might not suit smaller ears

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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