Short answer: the Fosi Audio IM4. Both are rated 4.2/5 for sound quality (#260 and #281 of 1291 in-ear headphones), and the Fosi Audio IM4 costs $99.99 against $105 for the Tin HiFi T6, so with nothing between them on sound quality, price settles it.
The case for the Fosi Audio IM4: The median of 18 hobbyist measurements gives it a very good Harman preference score of 76 with a 1.77 dB spread, and its mids sit within about 1.2 dB of target, so vocals and instruments sound natural. The tradeoff: A 4.6 dB peak near 8.2 kHz can make cymbals and sibilance sound sharp.
What the Tin HiFi T6 does well: The median of 14 hobbyist measurements gives it a very good Harman preference score of 76 with a 1.70 dB spread, and its mids sit within about 0.8 dB of target, so vocals and instruments sound natural. The tradeoff: A 4.3 dB peak near 8.2 kHz can make cymbals and sibilance sound sharp.
Buy the Fosi Audio IM4. Both are rated the same for sound quality, and it costs $5.01 less than the Tin HiFi T6.
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The median of 18 hobbyist measurements gives it a very good Harman preference score of 76 with a 1.77 dB spread, and its mids sit within about 1.2 dB of target, so vocals and instruments sound natural.
Amazon $99.99 eBay
The median of 14 hobbyist measurements gives it a very good Harman preference score of 76 with a 1.70 dB spread, and its mids sit within about 0.8 dB of target, so vocals and instruments sound natural.
Amazon $105.00 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
| Fosi Audio IM4 | Tin HiFi T6 | |
|---|---|---|
| Price | $99.99 | $105.00 |
| Ranked | #260 of 1291 in In-Ear Headphones | #281 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 76 (median of 18 squig.link measurements, calibrated to AutoEQ) | 76 (median of 14 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.77 dB standard deviation | 1.70 dB standard deviation |
| Tonal Tilt | -0.23 (negative is warmer, positive brighter) | -0.56 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-0.7 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+1.5 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Hybrid (1 dynamic + 1 planar) |
| Drivers | 1 x 10mm dynamic | 1 x 10mm dynamic + 1 x micro planar |
| Impedance | 21 ohms | 28 ohms |
| Sensitivity | 109 dB | - |
| Weight | 0 lbs (7 g) per earbud | 0 lbs (6 g) per earbud |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | 20Hz - 20kHz (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 Fosi Audio IM4 from atechreviews, audioamigo, boizoff, digaoreviews, elrics, hu-fi, jaytiss, joycesreview, musicafe, practiphile, pw, samreviews, soundcheck39, soundignity, superreview, theaudiostore, tonedeafmonk and treblewellxtended; the Tin HiFi T6 from atechreviews, audioamigo, csi-zone, fernandagunsan, hbb, hobbytalk, iemocean, jaytiss, kuping-sensi, samreviews, soundcheck39, soundignity, superreview and tonedeafmonk, all via squig.link.
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