Short answer: the EarAcoustic Audio SPA Limited Edition. Both are rated 4.0/5 for sound quality (#440 and #401 of 1291 in-ear headphones), and the EarAcoustic Audio SPA Limited Edition costs $429.90 against $449 for the Softears Studio 4, so with nothing between them on sound quality, price settles it.
The case for the EarAcoustic Audio SPA Limited Edition: A broadly balanced tuning with a preference score of 74 against the Harman target. The tradeoff: Treble about 2 dB above target from 3 to 10 kHz, which can sound sharp or tiring at higher volume.
What the Softears Studio 4 does well: The median of 27 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.88 dB spread. Watch for: Presence sits about 4.7 dB low with a 7.2 dB dip near 6.5 kHz, so vocals and instruments lose some bite.
Buy the EarAcoustic Audio SPA Limited Edition. Both are rated the same for sound quality, and it costs $19.10 less than the Softears Studio 4.
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A broadly balanced tuning with a preference score of 74 against the Harman target.
HiFiGo $429.90 eBay
The median of 27 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.88 dB spread.
Amazon $449.00 eBayPrices on this page were last checked October 16, 2026 at 5:46 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.
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Specifications Side By Side
| EarAcoustic Audio SPA Limited Edition | Softears Studio 4 | |
|---|---|---|
| Price | $429.90 | $449.00 |
| Ranked | #440 of 1291 in In-Ear Headphones | #401 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 74 (median of 3 squig.link measurements, calibrated to AutoEQ) | 74 (median of 27 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.12 dB standard deviation | 1.88 dB standard deviation |
| Tonal Tilt | +0.18 (negative is warmer, positive brighter) | -0.25 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-1.8 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-3.0 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Balanced Armature | Balanced armature |
| Drivers | 6 x balanced armature | 4 x balanced armature |
| Impedance | - | 12 ohms |
| Sensitivity | - | 123 dB/Vrms |
| Frequency Response | - | 5Hz - 40kHz (Manufacturer specified) |
| Built-in Microphone | - | No |
Frequency Response Compared
Both headphones’ measurements overlaid on the Harman target. Above the target sounds louder in that range, below it quieter. Each curve is the median of several independent measurements, shifted so its 500 Hz to 2 kHz average sits at 0 dB, so only the tuning is compared.
Measurement data: the EarAcoustic Audio SPA Limited Edition from atechreviews, ducbloke and hobbytalk; the Softears Studio 4 from aftersound, animagus, ankramutt, arc, atechreviews, audioamigo, awsmdanny, cammyfi, dl, doltonius, flare, gadgetrytech, harpo, iemocean, jaytiss, lestat, lumerion, musicafe, practiphile, precog, scboy, seanwee, sl0the, superreview, timmyv, treblewellxtended and vsg, all via squig.link.
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