64 Audio U4S VS Symphonium Helios SE

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The 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.

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Symphonium’s Helios arrives as a four-BA flagship with a spartan unboxing: a solid aluminum, waterproof “hockey-puck” case, multiple tip sets, and a standard 0.78 mm cable. Build is plain but substantial, and the shell is large with a wide nozzle—fit and comfort will be the biggest variable. The stock case’s rough threading and the cable’s lack of ear guides are minor gripes, but the overall presentation feels purposeful rather than flashy.

Tonally, Helios tracks Harman through the low mids, with a sub-bass-focused shelf and almost no mid-bass for maximum cleanliness—bass stays out of the mids and still slams impressively for BA. The midrange is clean and slightly lean (200 Hz dip, relaxed pinna gain) but well balanced. Treble is the showpiece: linear, extended, and airy to the edge of audibility, delivering uncommon “air” for the price. With Azla-style tips that air can verge on abrasive; swapping to the included silicone tips smooths the top end and improves coherence without dulling the sparkle.

Technicalities punch at the front of the kilobuck pack: resolution that hangs with class leaders, incisive imaging with uncanny “backwards” cues, and lively macro/micro-dynamics that give transients real snap. It may trail ultra-high-end sets by a hair in bass texture, but overall performance is compelling enough to edge out many peers. Verdict: an easy recommendation on sound alone, with the caveat to demo for fit—the shell size and nozzle girth will decide whether this brightest kilobuck star truly shines for you.

Youtube Video Summary

The 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.