Sendy Audio Apollo Review: Planar Headphones Featuring QUAD-Former Technology

Explore the Sendy Audio Apollo planar headphones with QUAD-Former technology offering exceptional comfort and rich, natural sound at $500.

Introduction to Sendy Audio Apollo

Sendy Audio Apollo headphones are a $500 (approx. 39.5k USD) offering boasting innovative QUAD-Former technology. In essence, these are planar magnetic drivers featuring dual magnets, two-sided coils, and dual coil rows — a combination designed to deliver superior audio performance. They stand shoulder to shoulder with notable models like Adam Audio Studio PRO SP-5, iBasso SR-2, Sennheiser HD660S, Dan Clark Aeon Flow RT, and Avantone Pro Planar in the same price bracket.

Sendy Audio positions itself as a premium sibling brand to Sivga, offering higher-end headphones while Sivga covers the entry-level market. The company is known for delivering a fantastic price-to-performance ratio and reliable products backed by solid warranties. Kudos to Sendy Audio for maintaining an impeccable reputation with no known widespread issues.

Just to clarify, this review is completely unbiased — no perks or promotional incentives were received. The goal is to help potential buyers decide if Sendy Audio Apollo could be their next musical companion.

Packaging

Let’s start with the unboxing experience:

The packaging is quite similar to the Sendy Audio Peacock model. Apollo comes in a sturdy cardboard box with a beautiful leather carrying case included. Inside, you’ll find a high-quality balanced 4.4mm cable plus a 4.4mm to 3.5mm adapter. There’s even a hemp bag for storing the cable and adapter, adding a nice touch of sustainability.

For the $500 price range, the packaging and included accessories feel premium and well thought out.

Build Quality, Aesthetics & Comfort

The heart of the Sendy Audio Apollo is a massive 68mm planar magnetic driver employing QUAD-Former tech — that means dual magnets paired with two-sided coils on the diaphragm. This doubled design raises the bar for sound reproduction, which we’ll dive deeper into later.

After three years of development, Apollo’s design is inspired by its namesake: the ear cups display a sunray pattern with a grill, while the frame uses glossy rosewood, blending aesthetics with acoustics. The construction is all about maximizing sound quality.

The headband is wrapped in ultra-soft goat leather, making these headphones slightly more comfortable than the Peacock model and far superior in comfort to the Sennheiser HD660S. The ear pads are thick and generous, designed like bowls to create a focused acoustic chamber for your ears. Plus, everything is marked clearly for left and right, and the pads are replaceable — a great feature for longevity.

The ear cups swivel in all directions with a durable, adjustable mechanism similar to the Sivga Peacock, ensuring a perfect fit for virtually any head shape or size. The thick ear pads and soft headband make them incredibly comfy for long listening sessions.

Weighing just 395 grams, the Apollo feels light and non-intrusive on your head. The clamping force is moderate, so no pressure points or discomfort even after hours of wear.

The included 6N OCC balanced cable tends to pick up minor noise if you walk around wearing the headphones, but this is negligible when stationary at a desk. With 95 dB sensitivity and 16-ohm impedance, the Apollo requires decent amplification. Using high-end players like iBasso DX220, iBasso DX240, Astell & Kern SP2000T, or Lotoo PAW6000 works best for these cans. For comfortable listening, my Astell & Kern SE180 needed about 100-150 volume at high gain.

Sound leakage is low but present, given the open-back design. Quiet to moderate volumes won’t disturb those nearby, but louder playback can be heard. Passive noise isolation is minimal, but at mid-level volume, the music drowns out keyboard clicks and fan noise.

Sound Quality Overview

The Sendy Audio Apollo delivers a relaxed, soft, largely linear, and natural sound signature with a mild warmth and musicality. It boasts an impressive soundstage and dynamic range with especially natural mids.

Using the Astell & Kern SE180 and Cyrus One Cast for amplification provided a clean, engaging listening experience. Apollo handles all volumes well — sounding more natural and balanced at low volumes and becoming more mid-focused and punchy at higher volumes.

Bass

The bass is warm with a natural, gently decaying note, creating a smooth, unforced low end. Unlike the more aggressive impact of the Sendy Audio Peacock, Apollo’s bass is soft, nuanced, and relaxed without head-shaking punches. It extends impressively down to 20 Hz.

Think of it as a very linear bass similar to what Etymotic in-ear monitors offer — perfect for mixing and mastering but less suited for EDM or electronic beats. It’s ideal for rock, metal, emo, post-hardcore, classical, jazz, and mellow genres.

Midrange

Middle frequencies are the star of the show. Apollo emphasizes mids over bass and treble, delivering some of the most beautiful, musical, and smooth midrange tones within this price segment. Both male and female vocals are silky, slightly dense, and lush.

Guitars sound notably rich, as if the designers had the Rosson RAD-0 in mind, aiming to capture its positive traits in a mid-centric headphone. The soundstage is wide and holographic, yet retains natural depth. Even harsh or screamo music sounds blissful, making Apollo a great pick for those who find harsh sounds tiring or want to hear pure musicality.

Piano notes are clear without harshness or sibilance, smoothing out the edges of tricky recordings.

Treble

Treble follows suit with ultra-clean, smooth, and fluid high frequencies — some of the purest highs I’ve heard in headphones. Initially, it might seem a bit subdued, but the highs naturally extend to the highest octaves while remaining silky and crisp. This gives Apollo a lively, exciting sound despite its smoothness.

Vocals stay soft and pleasant, and the treble presents an open feel, making you feel like you’re outdoors listening to a live performance.

Overall, Apollo suits nearly all musical styles unless you're craving heavy bass. The smooth treble and mid-forward signature make it perfect for rock, metal, pop, jazz, and downtempo, but less ideal for EDM, rap, or dubstep.

Bands like Bring Me The Horizon sound musical and refined, Katy Perry’s vocals are smooth and pleasant, and artists like Atilla and Chugaboom come through fun and fatigue-free even at high volumes. Apollo cleverly masks mastering flaws, turning poor tracks into pleasing soundscapes. The detail and clarity are excellent, but you’ll find yourself enjoying the music rather than dissecting technicalities.

Comparisons with Other Headphones

• Sendy Audio Apollo vs Dan Clark Aeon Flow RT ($500 each): Despite both having planar magnetic drivers, Aeon Flow RT is closed-back, Apollo is open. Apollo’s cable quality is superior, with a balanced cable and adapter included. Comfort favors Apollo thanks to thicker, softer ear pads and a gentler headband clamp. Sonically, Aeon Flow RT offers recessed mids, strong sub-bass, and sharp highs with a technical edge, while Apollo boasts mid-centric, smooth, relaxed sound.
• Sendy Audio Apollo vs iBasso SR-2 ($500 each): Both headphones share similar comfort, price, and sound signature: relaxed, natural, transparent, smooth. SR-2 has shallower, firmer ear pads, while Apollo’s are deeper and softer. SR-2 is slightly colder and bassier; Apollo warmer with smoother mids.
• Sendy Audio Apollo vs Sennheiser HD660S ($500 each): Apollo wins hands down for build and comfort compared to the tighter, harder HD660S. Soundwise, HD660S is more detailed, sharper, and punchier; Apollo is smoother, more musical, easier to enjoy over longer sessions. Both have comparable bass quantity, but Apollo’s slower note decay results in a less harsh sound.
• Sendy Audio Apollo vs Avantone Pro Planar ($500 vs $450): Comfort is similar, but Avantone has a more industrial look, whereas Apollo’s design is universally appealing. Avantone offers more bass depth and density; Apollo has a wider soundstage, richer mids, and more transparent highs. Apollo is lighter, more relaxed, and softer in presentation but can be source-dependent for best results.
• Sendy Audio Apollo vs Adam Audio Studio PRO SP-5 ($500 vs $550): Apollo beats SP-5 in comfort and build quality with larger, softer ear pads and a gentler headband. SP-5 is brighter, more detailed, and has a wider soundstage but can sound harsh and digital. Apollo is smoother, more musical, and mid-forward, pairing well with any source, whereas SP-5 benefits from a warm, rolled-off treble source.

Value and Conclusion

In summary, Sendy Audio Apollo offers outstanding value at $500. The build quality, comfort, included cables, and sound quality are exceptional for the price.

Comfort alone places Apollo in the audiophile hall of fame. If you desire an open, natural, and smooth sound with crystal-clear delivery, Apollo is the best option under $1000.

They replace the Sivga Audio P-2 in that elite category, with similar sound but better comfort, build, and a silkier, more musical signature.

Ultimately, Sendy Audio Apollo is a fantastic buy for anyone who loves to relax with music or craves beautiful, mid-centric sound. Their performance and quality make them a highly recommended choice for smooth, laid-back listening.

"Sendy Audio Apollo delivers some of the most beautiful, musical, and smooth midrange tones I've encountered in this price range." — Anonymous Reviewer

Frequently Asked Questions

• What is QUAD-Former technology in Sendy Audio Apollo?
  It’s a unique planar magnetic driver design featuring dual magnets, two-sided coils on the diaphragm, and dual coil rows, enhancing sound clarity and detail.
• Are Sendy Audio Apollo headphones comfortable for long listening sessions?
  Absolutely. With a soft goat leather headband and thick, plush ear pads, they’re among the most comfortable headphones in their price range.
• Do Sendy Audio Apollo headphones require a powerful amplifier?
  Yes, with a sensitivity of 95 dB and 16-ohm impedance, they perform best paired with a quality amplifier or high-end portable music player.
• How do Sendy Audio Apollo compare to Sennheiser HD660S in sound quality?
  Apollo offers a smoother, softer, and more natural sound with better comfort, while HD660S provides sharper detail and punch but is less comfortable.
• What genres suit Sendy Audio Apollo best?
  They excel with rock, metal, jazz, classical, and downtempo, but may not be ideal for bass-heavy genres like EDM or dubstep.

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