Short answer: a tie on sound quality. Both are rated 3.6/5 (#730 and #770 of 1291 in-ear headphones) at nearly the same price ($20.99 vs $20.99), so choose on features and fit.
The case for the TRN CS4: A very cheap single dynamic in-ear with a 69 Harman preference score and full sub-bass extension down to 20 Hz. The tradeoff: Its score rests on three measurements.
Why pick the TRN MT4: A very cheap 10mm dynamic IEM that measures close to the Harman target, with full sub-bass to 20 Hz (score 68 across six measurements). Watch for: A 2.27 dB spread from the target still leaves some peaks and dips.
Buy the TRN CS4 or the TRN MT4 on features: they are rated the same for sound quality at close to the same price.
Looking for alternatives? See the complete Headphones rankings.
A very cheap single dynamic in-ear with a 69 Harman preference score and full sub-bass extension down to 20 Hz.
Amazon $20.99 eBay
A very cheap 10mm dynamic IEM that measures close to the Harman target, with full sub-bass to 20 Hz (score 68 across six measurements).
Amazon $20.99 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
| TRN CS4 | TRN MT4 | |
|---|---|---|
| Price | $20.99 | $20.99 |
| Ranked | #730 of 1291 in In-Ear Headphones | #770 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 10mm dynamic | 1 x 10mm dynamic |
| Sensitivity | 106 dB/mW | 115 dB |
| Harman Preference Score | 69 (median of 3 squig.link measurements, calibrated to AutoEQ) | 68 (median of 6 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.25 dB standard deviation | 2.27 dB standard deviation |
| Tonal Tilt | -0.49 (negative is warmer, positive brighter) | -0.67 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.9 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.1 dB at 30 Hz) |
| Impedance | - | 22 ohms |
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 TRN CS4 from ankramutt, fahryst and ianfann; the TRN MT4 from hbb, hore, ianfann, pw, timmyv and tonedeafmonk, all via squig.link.
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