Review: Moondrop SSR – The Sunbeam Serenade

I would've named them Space Opera Supreme, since we're going full grandiose.
I would’ve named them Space Opera Supreme, since we’re going full grandiose.

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Moondrop’s latest has a fantastical and grandiose name, but at a very affordable price. Featuring a flat, diffuse-field neutral tuning, could this be the baby Etymotic you’ve been waiting for?

When the moon hits your eye like a big pizza pie, that’s… love? Lunar-related violence aside, Moondrop has been one of the most refreshing in-ear monitor (IEM) brands to appear as of late, winning acclaim and accolades with each new release. As you know I’ve taken quite a liking to Starfield, their budget superstar, and fervently look forward to their new releases and subsequent buzz.

Bottom Line

Moondrop’s SSR though, is willing to throw caution to the wind, and give a good go at a classic tuning. There’s no denying that you get more than your money’s worth in clarity, speed, note texture, and all the technical shenanigans. In the same tier, the SSR practically has no direct rival, and that alone might pique your interest, especially for the price of a few cups of fancy coffee.

What We Like 😍
  • Value for money
  • Petite design with robust build quality
  • Snug fit and excellent comfort
  • Class-leading detail level and transient response
  • Good note texture and definition
  • Bass detail and texture
  • Clear and forward mids
  • Clean staging with pinpoint imaging
  • Baby Etymotic!
What We Don't Like 🤢
  • Threadbare accessory set
  • Unergonomic cable
  • Poor isolation
  • Dry, cold sound
  • Inaccurate tone and timbre
  • Anemic bass
  • Strident, aggressive upper mids
  • Small soundstage

Hype Beast

Moondrop’s latest offering goes a tier lower in terms of price, and is called the SSR or Super Spaceship Reference, the nomenclature an ode to their earlier IEM, the Spaceship. In medical parlance, SSR stands for sick sinus rhythm, a disease of the heart that prevents it from maintaining a regular beat on its own. Nothing I can do, a total eclipse of the heart.

Moondrop’s heart-shaped SSR hopes to resuscitate your ailing heart and introduce rhythm into your life. Corny, I know.

The SSR is a tiny, reference-tuned IEM, housing a single dynamic driver (DD) in each earpiece. Why reference? As with other Moondrop releases, they’ve done their homework, and based SSR’s sound on the diffuse-field (DF) neutral signature. This is the first of a planned twin release by Moondrop, the other being the SSP, or Super Spaceship Pulse, featuring a fun, bass-oriented signature.

Where To Buy

The SSR is available in 4 colors, which are silver, white, pink and green. You can currently purchase them via :

I’d like to extend my thanks to the Moondrop team for the review unit.

Have a heart, give to chair-ity.
Have a heart, give to chair-ity.

Equipment Used:


  1. FiiO M15


  1. Moondrop SSR
  2. Etymotic ER4XR


  1. Amber Rubarth – Sessions from the 17th Ward
  2. Bruno Mars – 24K Magic
  3. Daft Punk – Random Access Memories
  4. Dua Lipa – Future Nostalgia
  5. Fleetwood Mac – Rumours
  6. Kendrick Lamar – DAMN.
  7. Lana Del Rey – Born To Die
  8. Melissa Menago – Little Crimes
  9. The Eagles – Hell Freezes Over
  10. The Weeknd – After Hours

Technical Specifications

  • Frequency Response: 20Hz – 40000Hz (1/4 Free-Field Mic)
  • Effective frequency response: 20Hz–20000Hz (IEC60318-4)
  • Driver: Beryllium-coated dome + polyurethane suspension ring
  • Housing material: Liquid metal alloy
  • THD: ≤ 1%
  • Cable Material: 24 AWG Litz 4N OFC
  • Cable Connectors: 0.78 2-pin
  • Sensitivity: 115dB/Vrms (@1khz)
  • Impedance: 16Ω (@1khz)
  • Voice Coil: φ 0.035mm-CCAW [Daikoku]
  • Acoustic Filter: Patented Anti-Blocking Filter
With more accessories than you can shake a stick… oh.
With more accessories than you can shake a stick… oh.

Packaging and Accessories

You have a waifu! The Moondrop girl is ubiquitous in their packaging as of late, and she adorns the front of the box, smiling, decently dressed, and using Moondrop IEMs as sort of a double advertisement. I know some fans love this, and frequently ask for her to be featured in more promotional material. Well, you do you, guys.

The SSR is packed in a square white cardboard box, displaying the technical specifications and frequency response graph at the back, and yes, your lovely waifu in front. The accessory kit is threadbare and disappointing. You get the IEM, cable, three pairs of silicone ear tips in varying sizes, a tiny fabric pouch and a manual. I would rather a zippered or hard case instead of the pouch, to better protect the SSR.

Cable Ramen

The provided cable looks much like Plastics One, but with quality insides, namely silver-plated 4N oxygen-free copper (OFC) with Litz wiring. Some similar cables already cost more than the SSR, so this is a smart move by Moondrop. The cable isn’t too stiff and has a rubbery feel, lessening Jada Pinkett-style entanglements. The ramen-like springiness and awful memory effect irks me though, so handling the cable isn’t good.

Petal to the metal.
Petal to the metal.

Design and Build Quality

Within these tiny earpieces are quite a bit of technology. The main driver is a beryllium-coated dome surrounded by a polyurethane suspension ring, retaining rigidity and flexibility. At the base of the driver is a copper-clad aluminium wire (CCAW) voice coil and a high-density magnetic circuit. When a current runs through the voice coil, a magnetic field is produced which moves the diaphragm.

The driver unit is protected by housing made of single-casted amorphous metal alloy, or liquid metal like T-1000 heh. The SSR’s long nozzle is at a right angle from the housing, and at its tip resides Moondrop’s patented 3-layered anti-clogging filter and acoustic damper unit. This combined filter/damper unit keeps earwax at bay, and shapes the sound before being directed towards the ears.


The tiny, heart-shaped SSR earpieces are lightweight and a delight to hold. Despite some visible corners, the edges are smooth and seamless and showcase a robust build quality. While not as pretty and aesthetically perfect as the Starfield, the SSR possesses an industrial charm with its simple and compact design. If I were you I’d choose pink though. That’ll make a great Valentine gift.

When you don't know which side to choose, sit on a big fence.
When you don’t know which side to choose, sit on a big fence.

Fit, Comfort and Isolation

When viewed from the side, the SSR is small enough to be mistaken for earrings. Earrings of steel hearts, baby. The shells measure only half an inch from all sides, coupled with the long nozzles confer a precise and snug fit. This is intentional so the SSR will fit ears of all sizes. Comfort is superb too, and I can lie on my side while listening. Moondrop did a great job here.

I can’t get over how tiny the SSR is. One sneeze and they might disappear.

The SSR has a vent on the base of the nozzle of each earpiece, to accommodate the dynamic driver. As such, keeping external noise levels as low as possible proves to be a challenge. They don’t isolate well at all. You’re out of luck in a busy environment, as outside noise more often than not seeps in and dilutes your enjoyment. It’s hard to be caught up in the music when real life interferes, as always.

Well, you asked for gold bars.
Well, you asked for gold bars.

Sound Quality

So far, the SSR has a lot going for them, but we arrive at the make-or-break sound section. Get ready your mittens.

Overall Sound Signature

As you know, Moondrop are teacher’s pets. They have studied, memorized, dissected, and re-interpreted the two cornerstones of neutral signatures ad infinitum, becoming masters of both DF and Harman-neutral. This is reflected throughout their product line, which showcases tweaked versions of both tunings. Curiously, DF-neutral is found in their most expensive IEM, the Solis, and the cheapest, the SSR.

DF-neutral, and SSR in effect, is characterized by a flat, sterile sound, or what I call textbook neutral. The emphasis is on detail retrieval and technical nuance above musicality and euphony. For better or worse, the signature works more as a tool for audio engineers to use as studio monitors, rather than something to kick back and relax with.

Harsh Light of Day

So SSR possesses a dry, textured bass that is uncolored and unenhanced, delineating every note clearly up to the mids. The mids is a stalwart of clarity and clinical precision, before taking it to another level in the upper mids, in what I can only describe as a detail-lover’s avalanche. Here, forwardness and aggression dictates proceedings until the lower treble, before retaining sensibility and rolling off in the uppermost regions.

Beyond the valley of the shadow of doubt.
Beyond the valley of the shadow of doubt.

It’s an intense ride not for the squeamish. Make no mistake, this is a musical scalpel, fully armed to extract every bit of detail from your music. The dedication to information is such that enjoyment very often takes a backseat, as you hear familiar song after song presented in bright, near-hostile fashion. Notes often have a thin, cold slant, and the question remains whether this kind of neutral is accurate at all.

Listening Conditions

Critical listening was done after 100 hours of burn-in, reducing the toxic levels of beryllium and hopefully making the signature easier to stomach. Unfortunately, nope. I hear no difference before and after burning in, so the cold dish of revenge, I mean neutrality, remains. The principal review rig is FiiO’s M15 player, with the included cable and medium ear tips.


Flat as a pancake and probably just as dry, SSR’s bass challenges your perception of just what a reference should be. Bassy instruments like cellos and drums normally share attributes like authority, slam, roundness and fullness, especially from a speaker system. But those words won’t really describe the SSR, in fact, it doesn’t sound true-to-life much.

The Nitty-Gritty

Instead, our ears are treated to a richly-detailed and well-layered bass section, with a palpable texture more akin to denim than silk. There is a bit of punch, warmth, and smoothness, but it’s more a case of dropping teasers and appetizers without arriving at the full meal. You won’t feel satiated, and the rough, gritty texture is definitely not for everyone.

The sub-bass performance is adequate, with a little rumble. The flat mid-bass will however, drive you nuts. You wait for the beat to drop and when it finally does, you think “that was it?” The SSR opens your ears to new bass frontiers, because you’ll hear details and layers that were not obvious previously. But when you want a physical bass to take you over, he takes out his reading glasses instead. This does not please the people.

It’s no secret I’m not a fan of diffuse-field neutral, and the anemic bass performance is the #1 reason why.

The lesson is, the real treasure has been inside your ears all along.
The lesson is, the real treasure has been inside your ears all along.


Like polar bears, the mids are the most polarizing factor of the SSR, both a highlight and a hindrance. First off, the SSR possesses outstanding clarity and transient response, probably unheard of in this price range. Notes are thin, tight, and hit with rapid precision, with clear separation from one note to the next. Mids texture is crunchy and delicate, providing heaps of energy and urgency. Decay is swift as well, leaving the stage clean and crisp.

Technically and tactically astute, that’s their name of the game.

For all the heroics in detail retrieval though, tonal accuracy takes a big knock, a TKO in fact. Mids are placed too forward and can be invasive and fatiguing. The note edges need smoothening too, as the dryness and grain distract and takes much away from emotional engagement. Vocals sound breathy and throaty, while instrument timbre is bright. You barely have time to feel or register a note before it’s hurried on to the next.

Icepick City

The worst is yet to come, as a steep rise in the upper mids results in a spiky and strident sound. Instruments trade body and fullness for tizziness and sharp edges, while ‘s’ and ‘t’ sounds are accented. Coupled with the raspy vocals, it’s a grating listen. The upper mids are like a car crash you can’t look away from, because it’s so prominent and forward it overwhelms the rest of the spectrum with its “hey-look-at-me” mannerism.

Take heed pal, I hear the signature's a real live wire.
Take heed pal, I hear the signature’s a real live wire.


Like turning over so your back gets as much sun as the front, the treble is just bathed in brightness. The adage “leave no stone unturned” is apt here, because every loving treble note is left bare, revealing oodles of micro-detail and shining, shimmering texture. It’s time to wear your sunglasses.

The lower treble continues the dirty work of the upper mids, working in tandem to provide a forward and crispy tone. Tons of sparkle are handed out, almost like a charity. Cymbals and hi-hats ring clear and true, with a bright, zingy finish. It’s perhaps too energetic and the notes could use more fullness, but there’s not much to fault with the timbre here at least.

Stairway to Pleasant

Thankfully, from the middle treble upwards, the SSR finally slows down and engages a lower gear, showcasing some restraint and control. No doubt smoothening over the edges here will deny the signature some air and spaciousness, but this provides much-needed respite from the unforgiving upper mids assault. Brightening the treble any further would’ve rendered the SSR unlistenable.

The true meaning of neutral is really a grey area.
The true meaning of neutral is really a grey area.

Soundstage and Imaging

As a kid, one of a litany of punishments I’ve endured after misbehaving was to stare straight at a wall, with the nose touching it. The SSR’s soundstage reminds me of that happy circumstance, ample width with almost no depth. Music occurs mostly inside the head, an effect of the forward mids placement. I am saved from further congestion thanks to the effective diffusion of sound to the left and right.

Claustrophobia aside, layering and separation are rather effective here, as the SSR displays astute technical chops in letting each note have its own space. The precise imagery and placement is of course enhanced, thanks to SSR’s thin notes and quick decay, since a clean stage allows details to pop out unabated. So it’s ice chips for dinner, hooray.

So near, sofa, so good.
So near, sofa, so good.


Etymotic ER4XR

You can’t mention DF-neutral without a nod to Etymotic, the godfather of IEMs. Etymotic built its name and entire legacy on the one signature other brands fear to tread, and sounds as distant from commercial as you can imagine. But you have to admire their grit and tenacity, sticking to their sound until today, like Absolut Vodka thriving on the same ad campaign for decades. Mmm vodka.

First off, this is not a fair, apples-to-apples comparison. The ER4XR is Etymotic’s current flagship and costs almost 10 times the SSR, and if you’re not in the mood to read further, the EX4XR is better. But I won’t be comparing them if SSR didn’t put up much of a fight.

Like Vader to Anakin

The ER4XR performs like a supercharged SSR. For all the SSR is capable of, the ER4XR boasts even better technical merits, with resolution and clarity hitting like a splash of cold, expensive water to the face. Moreover, the Etys sound more balanced because of increased bass presence and a tamer upper mids rise. These two factors alone make ER4XR the more complete IEM, with some fun thrown in for good measure.

The showdown of the ear-piercers.
The showdown of the ear-piercers.

While their signatures are more similar than not, ER4XR surges ahead with a distinctly dynamic and airier sound. This is possible thanks to the Ety’s quicker note decay, deeper and better-defined soundstage, and less aggressive upper mids. Music has more space to breathe compared to the borderline-uncomfortable intimacy of SSR.

Dark Horsing Around

Where the SSR surprisingly wins, is in tone and timbre. I’m not a fan of either one to be frank, but SSR sounds more natural and realistic throughout, compared to the Etys which fancy a bump in texture and brightness wherever possible.

The ER4XR is undoubtedly more energetic in the higher registers, but the upper treble presence lends a hot, digital glare to the tone. You can spot a tinny harshness throughout the spectrum especially if the recording is poorly mastered. There’s your scalpel at work.

When the dust settles, considering the much cheaper price, the SSR is the value-for-money prospect, easily positioning itself as a viable alternative to the mighty ER4XR, with better tonality to boot.

To answer an earlier question, yes, we’re looking at baby Etymotics here.

Waifu power overcomes all.
Waifu power overcomes all.

Final Words

At the day’s end, I am conflicted. The SSR and other DF-neutral monitors sound a country mile away from my preferred signature, and having one in my collection serves more of an academic purpose than anything else. There isn’t a day in the calendar where I’d like to listen to a cold and brutally honest interpretation of my music library. Like Jack Nicholson might say, I can’t handle the truth.

Cold Reality

Moondrop’s SSR though, is willing to throw caution to the wind, and give a good go at a classic tuning. There’s no denying that you get more than your money’s worth in clarity, speed, note texture, and all the technical shenanigans. In the same tier, the SSR practically has no direct rival, and that alone might pique your interest, especially for the price of a few cups of fancy coffee.

If nothing else, the SSR serves as a reminder of Moondrop’s tuning versatility, with an ever-expanding repertoire of tried-and-true sound signatures. And now, with a loyal fanbase, they are bolder and taking more risks with their innovations. In the works are a flagship-grade dynamic driver IEM and over-ear headphones. The sky’s the absolute limit for them.

💬 Conversation: 2 comments

  1. How does Starfield compares to SSRs – I know it’s more than twice the price of SSR, but if they are way better than SSR I’m willing to spend more for better product. Also what are your recommendations in $40-50 range.

    1. To me Starfield is vastly superior for my preferences. A warmer, more accurate tone throughout and a bigger soundstage. Unless you like a cold, precise and very neutral signature, Starfield gets my vote.

      In the $40 range there’s nothing better than Blon BL-03, I believe.

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