Short answer: both are discontinued, so this only matters if you are buying used. Used, the Sony IER-Z1R is the better pick: it ranks #328 of 909 in-ear headphones by sound quality (rated 4.0/5), against #560 (rated 3.4/5) for the Sony IER-M9. If you want one new, the ThieAudio Monarch MKIII ranks #1 at $999.
What the Sony IER-M9 does well: Lower mids sit within about 0.5 dB of target, keeping voices and guitars natural. The catch: Discontinued, so it is mainly found used.
The Sony IER-Z1R is the better-sounding option. Sony’s flagship hybrid IEM scores 74 on the Harman scale with a 2.14 dB spread and a warm tilt, with bass about 2 dB above target and smooth, inoffensive treble. Watch for: Discontinued.
Buy the Sony IER-Z1R only if you find one used in good condition; both are discontinued, and it is the better rated of the two. For a new speaker, start with the ThieAudio Monarch MKIII instead.
Looking for alternatives? See the complete Headphones rankings.
Specifications Side By Side
| Sony IER-M9 | Sony IER-Z1R | |
|---|---|---|
| Price | Discontinued | Discontinued |
| Ranked | #560 of 909 in In-Ear Headphones | #328 of 909 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Connection | Wired | Wired |
| Driver Type | Balanced armature | Hybrid |
| Drivers | 5 x balanced armature | 1 x 12mm dynamic + 1 x 5mm dynamic + 1 x balanced armature |
| Impedance | 20 ohms | 40 ohms |
| Sensitivity | 103 dB/mW | 103 dB/mW |
| Frequency Response | 5Hz - 40kHz | 3Hz - 100kHz (Manufacturer specified) |
| Weight | 0 lbs (11 g) | 0.1 lbs (26 g) |
| Harman Preference Score | 66 (measured by oratory1990, via AutoEQ) | 74 (measured by oratory1990, via AutoEQ) |
| Deviation From Target | 2.55 dB standard deviation | 2.14 dB standard deviation |
| Tonal Tilt | -0.59 (negative is warmer, positive brighter) | -0.40 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-2.2 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-1.9 dB at 30 Hz) |
| Back | - | Closed |
Related Headphone Comparisons
More worthwhile head-to-heads for Sony IER-Z1R:
- Final Audio A8000 vs Sony IER-Z1R
- BLON BL-03 vs BLON BL-03 II
- TRN Azure Dragon vs ZiiGaat Arete
- IKKO OH10 vs ZiiGaat Arete
- Fearless Audio Shangri-la vs ZiiGaat Arete
Prices on this page were last checked October 13, 2026 at 3:17 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Headphones In Full
Sony IER-M9 Discontinued eBay
Pros: Lower mids sit within about 0.5 dB of target, keeping voices and guitars natural. It uses 5 x balanced armature with an easy 20 ohm load.
Cons: Discontinued, so it is mainly found used. Presence sits about 4.1 dB low with a 7.1 dB dip near 6.0 kHz, so vocals and instruments lose some bite. A 7.2 dB peak near 11.2 kHz can make cymbals and sibilance sound sharp.
Full Sony IER-M9 review and specifications →
| Released | 2018 (8 years ago) |
|---|---|
| Connection | Wired |
| Deviation From Target | 2.55 dB standard deviation |
| Driver Type | Balanced armature |
| Drivers | 5 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 5Hz - 40kHz |
| Harman Preference Score | 66 (measured by oratory1990, via AutoEQ) |
| Impedance | 20 ohms |
| Sensitivity | 103 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-2.2 dB at 30 Hz) |
| Tonal Tilt | -0.59 (negative is warmer, positive brighter) |
| Weight | 0 lbs (11 g) |
EQ preset to match the Harman target
Set a preamp of -5.9 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by AutoEQ from its measured frequency response.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +0.6 dB | 0.70 |
| Peak | 178 Hz | -3.6 dB | 0.60 |
| Peak | 5,993 Hz | +5.7 dB | 3.10 |
| Peak | 2,555 Hz | +4.0 dB | 3.01 |
| Peak | 791 Hz | +1.2 dB | 1.57 |
| High shelf | 10,000 Hz | -6.3 dB | 0.70 |
| Peak | 7,703 Hz | +1.4 dB | 1.76 |
| Peak | 3,487 Hz | -1.9 dB | 6.00 |
| Peak | 3,917 Hz | +1.3 dB | 5.98 |
| Peak | 1,862 Hz | +0.3 dB | 3.22 |
- Reviews, Comparisons and Sound Samples
Sony IER-Z1R Discontinued eBay
Pros: Sony’s flagship hybrid IEM scores 74 on the Harman scale with a 2.14 dB spread and a warm tilt, with bass about 2 dB above target and smooth, inoffensive treble.
Cons: Discontinued. A 7.2 dB dip near 2.7 kHz softens vocal presence, and sub-bass is 1.9 dB short at 30 Hz. Its price is very high for a 74 Harman score.
Full Sony IER-Z1R review and specifications →
| Released | 2018 (8 years ago) |
|---|---|
| Back | Closed |
| Connection | Wired |
| Deviation From Target | 2.14 dB standard deviation |
| Driver Type | Hybrid |
| Drivers | 1 x 12mm dynamic + 1 x 5mm dynamic + 1 x balanced armature |
| Form Factor | In-ear |
| Frequency Response | 3Hz - 100kHz (Manufacturer specified) |
| Harman Preference Score | 74 (measured by oratory1990, via AutoEQ) |
| Impedance | 40 ohms |
| Sensitivity | 103 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-1.9 dB at 30 Hz) |
| Tonal Tilt | -0.40 (negative is warmer, positive brighter) |
| Weight | 0.1 lbs (26 g) |
EQ preset to match the Harman target
Set a preamp of -5.9 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by AutoEQ from its measured frequency response.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +1.1 dB | 0.70 |
| Peak | 141 Hz | -3.0 dB | 0.53 |
| Peak | 2,630 Hz | +6.1 dB | 3.17 |
| Peak | 584 Hz | +1.2 dB | 0.71 |
| Peak | 1,447 Hz | -1.9 dB | 2.21 |
| High shelf | 10,000 Hz | -2.5 dB | 0.70 |
| Peak | 9,775 Hz | +1.7 dB | 1.16 |
| Peak | 3,704 Hz | -1.8 dB | 4.99 |
| Peak | 5,109 Hz | +2.7 dB | 5.93 |
| Peak | 5,999 Hz | -2.2 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons