Short answer: the Rumaudio Blues. It ranks #664 of 1291 in-ear headphones by sound quality, rated 3.7/5, at $199; the Penon Vortex ranks #754, rated 3.6/5, at $199. The price gap is small enough that the sound-quality ranking should decide it.
Why pick the Rumaudio Blues: An all balanced armature IEM with six drivers per side. The catch: Bass sits about 2.0 dB below target, so it sounds lean.
What the Penon Vortex does well: A broadly balanced tuning with a preference score of 69 against the Harman target. Watch for: Treble about 2 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
Buy the Rumaudio Blues. It is rated higher for sound quality than the Penon Vortex at the same price, so only choose the other one for a particular feature it does better.
Still deciding? The full Headphones rankings cover every ranked option.
An all balanced armature IEM with six drivers per side.
Shenzhenaudio $199.00 eBay
A broadly balanced tuning with a preference score of 69 against the Harman target.
Penon Audio $199 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
| Rumaudio Blues | Penon Vortex | |
|---|---|---|
| Price | $199.00 | $199 |
| Ranked | #664 of 1291 in In-Ear Headphones | #754 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Connection | Wired | Wired (3.5mm / 4.4mm) |
| Driver Type | Balanced Armature | Dynamic |
| Drivers | 6 x balanced armature | 1 Dynamic (10mm DLC & beryllium-plated) |
| Harman Preference Score | 70 (median of 4 squig.link measurements, calibrated to AutoEQ) | 69 (median of 3 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.43 dB standard deviation | 2.54 dB standard deviation |
| Tonal Tilt | +0.25 (negative is warmer, positive brighter) | -0.04 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-4.7 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-5.3 dB at 30 Hz) |
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 Rumaudio Blues from audioamigo, bedrock, flare and soundcheck39; the Penon Vortex from harpo, jaytiss and tgx78, all via squig.link.
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