AQUA Audio Amplifier Initial Impressions

First off, my IEM taste might be a bit biased at this point -- I've been through a lot of IEMs in the past (and have a bunch left around for comparison listening), but I've been using Westone W60 IEMs for the past year, and that's a hard comparison for any IEM, let alone one that comes in at a fifth of the price (or a tenth if you were an Indiegogo supporter, like me). Also, after a few minutes of listening with the default white filters, I decided to go for the black (balanced) ones instead. (Side note: did anyone else have an almost impossible time trying to take those bloody things out of the package? I ended up having to use a box cutter to dig the replacement filters out!) All testing was done with those. Also, I did not perform any burn-in due to technical issues with my burn-in setup.
 
My test methodology for a new IEM is pretty lengthy: I run through a TIDAL sample playlist straight out of my iPhone 6S+ (since that's my default listening mode), then the same playlist using my Oppo HA-2 amp. If I am curious, I may then use some songs from the same playlist through my Mac and Fiio E17.
 
First impressions (iPhone 6S+, no amp)
 
I Am John (Loney Dear): great start to the song, but as the tempo and instrumentation builds, things get a little congested and clarity suffers. The music is still engaging and fun, but it doesn't have the crispness that I'm used to with my Westones.
 
Pompeii (Bastille): This song is very obviously mixed a little hot and with mostly digital instrumentation. It tends to sound good with almost anything, and these phones are great. Plenty of bass and the highs comes through clean.
 
Torn Blue Foam Couch (Grand Archives): Some sibilance showing up on this song, as well as a little bit of congestion. Some of that is actually the recording, though. It's still fun to listen to, with a surprising amount of bass impact and presence. Also, I'm just noticing how enveloping the sound stage is.
 
Jumpin' at the Woodside (Ellington/Basie, First Time version): This is a tough test track. Lots of things going on. Lots of spacial variation. And I know the song very very well. Surprisingly, the high horns don't blow out my ears, which makes me think the sibilance on the last song was as much recording artifact as something from the headphones. Even when both orchestras get going, parts are cleanly discernible, although I suspect that my Westones are a little better at separation. The soundstage is really quite excellent, and the decay on the final piano note is lovely.
 
Memphis Soul Stew (King Curtis): Another test track with a great deal of separation and some really isolated and pretty instrumental pieces. The instruments sound fantastic, although King Curtis's vocals have just a little bit of edge to them. 
 
Let It Be (Claudia Lennear, Live Santa Monica Civic version): Bass and background is lush and full, Lennear's vocals are almost a little recessed compared. The reproduction of her voice is detailed and rich, though. 
 
The Flag (Barenaked Ladies): I've been listening to this song for 20 years through so many systems that it makes a great personal test. The cello is detailed and lively (which isn't always the case, since it's not recorded particularly well). Page's voice is clear as a bell with surprisingly minimal sibilance. Strangely, the bass at the tail end of the song does not hit that hard or extend as low as I'm used to. 
 
9 Crimes (Damien Rice): Breathy female vocals are breathy. Again, the music has a lush feeling, with impact on the bass hits and a clear spacial distinction between the two singers and their background instrumentation. 
 
Two Step (Bear Mountain): Plainly put, this song rocks. It's all electronic, and it has slam and energy and just sounds fun.
 
Artillery (Infected Mushroom): Everything is clear as a bell. Bass extends low and sounds pretty fantastic. This is not really a challenging track, because it's recorded super clean, but it makes these IEMs sing. Whispered and layered vocals maybe aren't quite as clean as they are with my Westones or when I tested the Oppo PM-3 cans on this song, but that's pretty rarified territory. Bottom line is that is sounds great. 
 
The Boxer (Jerry Douglas, Mumford & Sons, Paul Simon): I used this track to test an awful lot of gear at CanJam. Lots of quiet, distinctive parts, and also a lot of very busy, crowded, and layered bits. The intro is really good -- bass is strong and filling without overpowering Mumford's vocals, and the guitar sounds lively. As the music swells, the parts blend maybe a little, but not in a white noise way. It's more like how a chord resolves and is almost perceived as a single sound.
 
Second phase (using the Oppo HA-2 DAC/Amp):
 
I am John (Loney Dear): Slight sibilance on vocals throughout the song. Separation is definitely a little better, but as the song gets more crowded, the sibilance gets worse.
 
Artillery (Infected Mushroom): Minor improvement over the naked version -- the clarity on the whispered/layered vocals is definitely improved. 
 
Torn Blue Foam Couch (Grand Archives): Separation is definitely improved over the naked version and the sibilance that was apparent before is greatly reduced. Can't stop tapping toes.
 
9 Crimes (Damien Rice): Piano sound is definitely leaner and tighter. Everything is a bit more accurate. Still not a sound that I'd call analytical -- it's fun to listen to. 
 
Jumpin' at the Woodside (Ellington/Basie, First Time!): Layering is definitely improved. Soundstage is still very good, although the HA-2 might be making it just a little narrower. At the climax of the song, there was just a bit of top end interference.
 
Pompeii (Bastille): I feel like the bass might actually vibrate my entire spine. Zowie. Again, almost a little too much on the top end, but it's right on the line. 
 
The Boxer (Jerry Douglas, Mumford & Sons, Paul Simon): Definitely tighter and more detailed. The layered and complex parts sound fantastic. No apparent sibilance or upper register harshness.
 
Memphis Soul Stew (King Curtis): Leaner sound, better reproduction of King Curtis's voice. Still has great slam on the drum and good spacial separation for instruments. 
 
Since there wasn't all that much difference between the naked iPhone and HA-2 version, I decided I didn't need to go through again with the Fiio E17.
 
Overall impression:
 
Very fun headphones that are easy to drive and benefit some from improved source and amp. I don't know that I'd recommend them for classical, but they hold up to jazz and funk pretty well and sound great with electronic and pop music. Build quality is first rate, and the differently-tuned filters give some ability to customize to your tastes. Isolation is excellent and tip selection is really good, plus they are so light that you barely notice they're in your ears. They have a great bass sound and tone with no midbass bump (which I hate!) and nice soundstage and imaging, especially for such tiny phones. 
 
Comparisons:
 
vs. W60: The Finders definitely have a lusher sound, occasionally verging on harsh. Great soundstage and spacial separation for in-ears, and they have a good bass presence, although the W60 has better extension and texture. 
 
vs. Ety ER-4P: This is kind of a silly comparison, since they're really entirely different phones. The Finders have a much wider soundstage and fuller low end, with an active but sometimes uncontrolled high end. The ER-4P are all about analytical precision.