Sendy Audio Apollo Pro

Sendy Audio’s Apollo Pro — A Supremely Comfortable, Warm-Sounding Guilty Pleasure

Sendy Audio is the audiophile-focused sister brand to Sivga, both from the same Dongguan-based company. My previous experience with Sendy Audio specifically was the excellent Egret, and while I have reviewed plenty of the sister brand’s headphones too — the Luan and the Robin SV021 Pro among them — I was genuinely excited to try the Apollo Pro.

On paper it looks like it combines the best of what the two companies each do well: the refined sound quality and higher build quality of the Sendy Audio Egret, paired with comfort close to the Sivga Luan’s thanks to similar earpads. In my opinion that is a great combination for anyone looking for a decent headphone. So does the sound live up to those expectations? Read on to find out.

The Apollo Pro is a substantial retune of the original Apollo, built around a 78mm planar magnetic driver, and having spent three weeks with it, the sound signature has moved on a lot from that first version. It retails at €499 ($449 / £449).

I have been listening to the Apollo Pro for three weeks now. The tuning won’t suit everyone, but taken as an overall package I think it makes for a very pragmatic headphone, with comfort and sound that aims well above its price point. But first, let’s take a look at what’s in the box.

Unboxing and Build Quality

The Apollo Pro arrives in a plain kraft box with a line-drawing illustration of the headphone’s distinctive sunburst grille on the front:

The back of the box prints the core specification in both English and Chinese, alongside the Sendy Audio logo:

Inside sits a high quality leather carrying case, embossed with the Sendy Audio logo and finished with brass hardware — though like a lot of Sivga and Sendy Audio cases, it has a tendency to look a bit like a human posterior:

Inside the case, the headphone sits with a linen Sendy Audio drawstring bag tucked into the headband cavity:

The box includes: the Apollo Pro headphone, the leather carrying case, a hemp accessory bag, a 4.4mm balanced cable, a 3.5mm-to-4.4mm adapter, and a 6.35mm-to-3.5mm adapter. The cable itself is a triple-composite build — Furukawa OFC, silver-plated, and gold-plated copper strands woven together with shielding to cut noise — coiled neatly with the adapters and a cable tie:

The two adapters ship individually bagged for protection:

The stock cable itself is high quality — the triple-composite build feels premium — it’s just a minor niggle that it’s on the heavier side, so worth bearing in mind if you’d want something shorter for portable use. One thing to be aware about the cable is its compatibility: the two earcup sockets aren’t interchangeable in what dual 3.5mm cables they’ll accept. Held up against each other, the left plug has two rings (moulded for the left socket) while the right socket specifically requires a single-ring plug rather than the double-ring style. The important thing is that this is an electrical difference, not a mechanical one — a double-ring plug goes into the right socket perfectly happily, it just doesn’t pass audio, so there is nothing to feel or hear that tells you the cable is wrong:

The sockets sit on the underside of each earcup and the plugs are marked L and R, so there is no ambiguity about which goes where.

In practice none of this matters unless you go shopping for a replacement, because the stock cable is good and you have no particular reason to change it. The one thing worth knowing is the convention: this is dual 3.5mm in the same broad sense that Meze and Final Audio use it, not the HiFiman variant. A HiFiman-style double-ring cable will plug in without complaint and simply won’t pass audio on the right channel — which is a more confusing failure than an outright mechanical mismatch, because your instinct is to blame the source or the headphone rather than the cable. Sivga’s own single-ring cables do work, including the one bundled with the Robin SV021 Pro V2. So if you ever do replace it, look for single-ring or Sivga-compatible terminations rather than assuming a generic HiFiman cable will work.

Build quality on the headphone itself is excellent for the price. The earcup grille uses a sunburst metal mesh pattern over the 78mm planar driver, set inside a CNC aviation-aluminium frame:

Sivga and Sendy Audio are well known for their gorgeous use of wood, and the zebrawood earcup here is worth a closer look on its own — the high-gloss finish catches the light nicely where the cup meets the CNC aluminium frame and the cable exits at the bottom:

Fit and Comfort

At 354g — confirmed on my own kitchen scale, matching Sendy Audio’s spec exactly — the Apollo Pro carries that weight well: it feels lighter on the head than the number suggests, even with its large earcups, and the comfort is genuinely excellent, arguably the best I’ve experienced from Sendy Audio or Sivga to date:

The earpads are breathable velvet with a soft lamb-leather headband, and the depth and softness of the pad cushioning is a real strength — I could happily wear glasses without it meaningfully affecting the bass response, which is not something I can say about most headphones that are this comfortable — usually a high clamping pressure is needed to keep a good bass seal, but it seems like the extra-wide pads nicely wrap around your glasses, at least they did with mine, though my glasses are not that thick:

Compared against a few of the other Sivga and Sendy Audio earpads in the collection, you can see they’re similar to the Sivga pads but a little different from the sculpted earpads on the Egret, which are more prone to being affected by a broken seal:

The pad material itself is breathable velvet and does a good job of it, but the exceptionally hot summer we have been having in Europe turned up one caveat: on a genuinely hot day it can still get very warm inside these ultra-comfortable earpads. That is a function of size rather than material — they are large pads covering a lot of your ear and the surrounding side of your head, which is exactly what makes them so comfortable the rest of the year, and on a heatwave afternoon means they work rather like earmuffs. Worth factoring in if you listen for long stretches somewhere without air conditioning.

Sound Impressions

I listened to the Apollo Pro over three weeks from both my work-from-home desktop setup with a Topping DX5 II, and using the Crinear Protocol Max connected directly to both my iPhone and my MacBook Pro, rotating it against several other planars and against the Egret. The overall character has a bit of that “high-end Meze” warmth to it, paired with a spicier top end than that comparison usually implies, and — thanks to the open design — a touch of that expansive Hifiman soundstage effect. That “high-end Meze” warmth is really the key aspect of why this headphone might be a guilty pleasure to some, and won’t appeal to others — for me, though I like plenty of different sound signatures, I really liked it: it’s basically a pleasant colouration that should appeal to anyone who likes some of the warmer Meze headphones.

Everything described below is the stock tuning, which is how I listened for the first few weeks and enjoyed it. After that I switched to the four-filter PEQ set out in the measurements section, which trades the warm lower-midrange lift for a firmer bass shelf and takes a little heat out of the top end — and having lived with both, that is where I ended up staying. It is not a correction of a fault so much as a choice between two versions of the same headphone: the stock voicing is the more comfortably indulgent one, the EQ’d version the more even-handed, and which you prefer will come down to how much warmth you want on a long listen rather than which is more accurate.

Bass

The bass is warm without tipping into bloated or muddy territory — nicely controlled for an open-back planar, with enough weight to feel satisfying without ever overstaying its welcome in the mix. On “xanny” by Billie Eilish, the sub-bass has real presence and texture without smearing into the vocal, which sits just above it.

Midrange

The midrange carries that Meze-adjacent warmth I mentioned, with a natural, inviting quality that never feels thin or clinical. It’s an engaging presentation rather than a strictly neutral one, and it suits vocal-forward material particularly well. On “Fade Into You” by Mazzy Star, the vocal has real body and warmth without ever feeling pushed forward artificially.

Treble

The treble is where the Apollo Pro breaks from that warmth with a genuinely spicy edge — well extended and detailed, but with real energy up top that’s the one area where I’d flag a caveat: some listeners may find it a little hotter than they’d like, particularly coming from a warmer, more relaxed-treble headphone. On “Chocolate Chip Trip” by Tool, the cymbal work and percussion have good detail and air, though on brighter recordings that extra energy is more noticeable.

Soundstage and Imaging

Soundstage is a genuine highlight — the open-back design delivers a real sense of space, closer to what I’d expect from a Hifiman planar than from most other Sendy Audio or Sivga headphones I’ve used. On “Born, Never Asked” by Laurie Anderson, the layered vocal treatments spread out well beyond the earcups, with good separation between elements even in a fairly dense mix.

Comparisons

Within Sendy Audio’s own range, the Apollo Pro sits alongside the Egret as one of the two most complete tunings the brand has produced. The Egret leans toward authoritative planar bass and a composed midrange; the Apollo Pro trades a little of that bass authority for a more open, spacious presentation and a warmer overall character. Both are excellent, and the choice between them comes down to whether you prioritise the Egret’s bass weight or the Apollo Pro’s soundstage.

Against the Sivga Luan, the family resemblance in comfort philosophy is obvious — both prioritise exceptionally soft, breathable padding — but the driver technology and tuning are quite different. The Luan’s 50mm dynamic driver has a warm midrange with a brighter treble boost around 15kHz, while the Apollo Pro’s planar driver gives it a more open, spacious presentation that the Luan’s more conventional dynamic design doesn’t attempt to match. Pictured together with a wider selection of Sendy Audio and Sivga headphones, the family design language — wood, leather, and metal — is easy to spot across the range:

Against the Sivga Robin SV021 Pro, the comparison is really one of price tier and ambition. The Robin SV021 Pro is an impressive $200 closed-back once EQ’d, but its stock midrange needs that correction to sound its best. The Apollo Pro, at more than double the price, doesn’t need that intervention — it’s well-balanced out of the box, with a substantially more spacious open-back presentation that the closed-back Robin was never going to deliver.

Against the Sennheiser HD600, the Apollo Pro’s planar driver and warmer tuning make for an interesting contrast with the HD600’s more classically neutral, midrange-forward accuracy. The HD600 remains the more analytically “correct” of the two, but the Apollo Pro’s open, spacious presentation and warmer bass make it the more immediately engaging listen for a lot of music.

Against the Hifiman Edition XV, the comparison is closest in spirit — both are open-back planars in a similar price bracket with a relatively easygoing, non-fatiguing character. The Edition XV’s treble is more deliberately relaxed than the Apollo Pro’s, which makes it the safer choice for treble-sensitive listeners, while the Apollo Pro counters with a touch more warmth through the midrange and a comfort package — that leather case, those earpads — that goes well beyond what Hifiman includes at this price.

Against the Sendy Audio Egret (loose clamp) and the Sivga Robin SV021 Pro, measured together the family relationship is clear — all three share the same warm lower-midrange lift, with the Apollo Pro and Egret tracking closely and the closed-back Robin SV021 Pro falling in a little further back through the same region:

Beyond the Sendy Audio and Sivga family, I also measured the Apollo Pro against a few headphones I’ve reviewed with a similar warm, Meze-adjacent midrange character, to put a number on how warm it actually is. First, against the FiiO FT7, the Grell Audio OAE2, and the Hedd Audio HEDDphone D1, pictured here left to right along with the Apollo Pro itself:

The Grell Audio OAE2 is the more quality-over-quantity headphone of the two through the bass, and its midrange is the more neutrally balanced of the group — a real strength of that headphone, but it means the Apollo Pro reads noticeably warmer sitting next to it. The FiiO FT7 is the closest of the three in overall shape through this region, tracking the Apollo Pro’s lift for a good stretch before settling into its own excellent, more neutral balance in the pragmatic review of the FT7 — again leaving the Apollo Pro as the warmer of the pair. The HEDD Audio HEDDphone D1 is the outlier here: I’ve called the D1 class-leading for midrange transparency, and next to that reference-flat midrange the Apollo Pro’s warmth is easy to see and hear.

And against a cluster of other headphones I associate with that “high-end Meze” warmth — the Sennheiser HD490 Pro (Producing pads), Meze 105 SILVA, and Meze 109 Pro, pictured here alongside the Apollo Pro:

The Apollo Pro consistently measures as the warmest of the group. The Sennheiser HD490 Pro on its Producing pads leans toward a deep, spacious sound rather than a heavy midbass lift, so it tracks the target more closely through this region than the Apollo Pro does. The Meze 105 SILVA carries some of that familiar Meze mid-bass richness, but doesn’t push it as far as the Apollo Pro does here. The Meze 109 Pro is probably the closest in spirit — Meze’s own description leans on a “full-bodied midbass” — but even there the Apollo Pro’s lift measures as the larger of the two. I no longer have a Meze Empyrean II with the Duo earpads to include in this round of measurements, but for reference, here’s how the Apollo Pro compared against the Empyrean II Duo and the 109 Pro when I measured it previously:

Specifications and Measurements

At 27Ω and 93dB sensitivity, the Apollo Pro is an easy planar to drive — nothing here demands a particularly powerful amplifier, though as always a clean source will let the driver show what it can do.

I have now measured the Apollo Pro myself. Channel matching between left and right is close, and I’ve marked the three regions that line up with what I heard in listening: (1) the warm lower-midrange lift that’s behind the “high-end Meze” character, (2) a small presence-region dip, and (3) the treble bump that gives the Apollo Pro its spicier top end:

Here’s the same left/right channel data again, this time plotted against the flatter KB501X diffuse-field target rather than the Harman OE 2018 curve used above — useful if you prefer to judge against that reference instead:

For reference, here’s an earlier measurement pairing the Apollo Pro against the Meze 109 Pro and the Meze Empyrean II Duo directly — the Apollo Pro tracks close to the 109 Pro through the warm lower-midrange region discussed above, while the Empyrean II Duo pushes that same region a little further still:

Distortion is very low across the band — there’s nothing here that shows up as a practical concern at normal listening levels:

Suggested PEQ — a firmer bass shelf, and the rest left broadly alone

The warm lower-midrange lift is the defining characteristic of this headphone, and if you like it there is nothing here you need to fix. But if you want the bass to behave more like a conventional Harman-style shelf — weight low down rather than warmth further up — while keeping the Apollo Pro recognisably itself, it turns out to be a small job. Here is the direction, stock in blue against the EQ’d result in green, plotted against Harman OE 2018:

The wide cut at 200 Hz is doing the real work: it pulls down the broad lower-midrange bloom that gives the stock tuning its warmth, and once that comes down the bass reads as weight rather than thickness. The narrow lift at 600 Hz fills the small dip that opens up as a consequence. The other two filters are gentler shaping — a broad lift around 2 kHz that addresses the presence-region dip highlighted earlier, and a wide high shelf from 6 kHz that takes a couple of dB out of the spicier top end.

Four filters and a preamp, which you can apply directly to a supported DAC or dongle here:

A note on that last filter, because it is a deliberate choice rather than an oversight. It is tempting to point AutoEQ at the treble, since above roughly 5 kHz the measurement shows a series of sharp peaks and deep nulls that look like obvious targets — the null near 10 kHz in particular drops around 10 dB. I would not do it. That region is where a coupler measurement is least representative of what actually happens on a real head: those narrow features move in frequency and depth with pad seal, positioning and individual ear geometry, so a filter chain built to flatten them on this rig can easily make things worse on yours. A single broad shelf, as used above, is the robust answer — it is one control, it survives all the variation the rig cannot capture, and you can set it by ear from there.

Rating Explanation

The Pragmatic Rating of 5 reflects a headphone with nothing significant to complain about — the style won’t suit everyone, but beyond that this is one of the best Sendy Audio or Sivga headphones you can buy, right up there with the Egret. I’ll be honest that part of this score is a personal soft spot: I liked the warmer sound and I loved the comfort, and I can understand listeners who don’t want that much warmth in their bass marking it down for that reason — for me it was a guilty pleasure rather than a flaw. The Price Rating of 5 reflects excellent quality across the board for the money — the leather case, the cable, the build, and above all the earpad comfort all feel like they belong on a considerably more expensive headphone.

The Features Rating of 4 reflects an accessory package that is generous rather than exhaustive: you get one cable, terminated in 4.4mm balanced, and rely on the two supplied adapters for anything else, where some rivals at this level ship a second cable with a different termination. The Measurements Rating of 4 reflects a nicely controlled response that leans a little warmer than some listeners will prefer, without ever becoming bloated or muddy — a deliberate tuning choice rather than a flaw, but one that keeps this just short of a 5 for anyone chasing strict neutrality.

This one is for anyone who wants an open, spacious planar sound with exceptional comfort, and who doesn’t mind a distinctive look in exchange for one of the most complete packages Sendy Audio currently offers.

Conclusion

The Sendy Audio Apollo Pro is a very pragmatic open-back planar, and probably the brand’s most complete headphone yet. The comfort is outstanding, the looks are distinctive even if not universally to everyone’s taste, and the warm, open, well-balanced sound signature — with just a little extra treble energy for some listeners to be aware of — makes for a genuinely enjoyable long-term listen. Alongside the Egret, it’s the clearest evidence yet that Sendy Audio and Sivga know exactly what they’re doing.