Short answer: the Etymotic ER4XR. Both are rated 3.0/5 for sound quality (#982 and #1000 of 1291 in-ear headphones), and the Etymotic ER4XR costs $229.99 against $239 for the FatFreq x HBB Deuce, so with nothing between them on sound quality, price settles it.
What the Etymotic ER4XR does well: Upper mids sit within 0.5 dB of the Harman target and low mids within 0.4 dB, so vocals and instruments come through clearly and naturally. The catch: Sub-bass is about 7.2 dB under target and bass is 2.6 dB low, so kick drums and bass lines lack weight and rumble.
The case for the FatFreq x HBB Deuce: Lower mids sit within about 0.5 dB of target, keeping voices and guitars natural. The catch: A Harman score of 61 places it in the lower part of the in-ear rankings.
Buy the Etymotic ER4XR. Both are rated the same for sound quality, and it costs $9.01 less than the FatFreq x HBB Deuce.
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Upper mids sit within 0.5 dB of the Harman target and low mids within 0.4 dB, so vocals and instruments come through clearly and naturally.
Amazon $229.99 eBay
Lower mids sit within about 0.5 dB of target, keeping voices and guitars natural.
Bloom Audio $239.00 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
| Etymotic ER4XR | FatFreq x HBB Deuce | |
|---|---|---|
| Price | $229.99 | $239.00 |
| Ranked | #982 of 1291 in In-Ear Headphones | #1000 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Harman Preference Score | 62 (measured by oratory1990, via AutoEQ) | 61 (median of 22 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 3.06 dB standard deviation | 2.82 dB standard deviation |
| Tonal Tilt | +0.61 (negative is warmer, positive brighter) | -1.30 (negative is warmer, positive brighter) |
| Sub-bass Extension | Falls 6 dB below target at 47 Hz (-7.0 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+6.3 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Balanced armature | Dynamic |
| Drivers | 1 x balanced armature | 2 x dynamic |
| Impedance | 45 ohms | - |
| Frequency Response | 20Hz - 16kHz (Manufacturer specified) | - |
| Back | Closed | Closed |
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 Etymotic ER4XR from aden, dchpgall, dentreviews, musicafe, precog and superreview; the FatFreq x HBB Deuce from aden, adri-n, aftersound, audioamigo, bassaudio, bassyalexander, bloomaudio, ducbloke, eliseaudio, harutohiroki, hobbytalk, jaytiss, joycesreview, koi, kr0mka, pw, sl0the, soundignity, superreview, theaudiostore, therollo9 and tonedeafmonk, all via squig.link.
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