I'll begin this review by telling you a little about my audio biases. My first love is not portable audio (though this is changing); I prefer big speakers properly arrayed for surround sound paired with a hefty subwoofer capable of moving a lot of air. Alas my current living conditions as well as an increasing amount of time spent travelling have pushed me in the direction of something smaller and more practical. Though I've heard some nice over ear and on ear cans I prefer the form factor, size and aesthetic of canal phones. For me IEMs do several things well; one is to present music intimately and the other is to offer up detail and clarity that add new dimensions to my favourite songs. Up until recently I've been dabbling in the universal IEM market and I've come to realize that everything I've heard/own is a series of compromises. The Etymtoic HF2 is very intimate and detailed but not very dynamic and lacking a little in the low end. The Re-262 has some nice mids but the bottom and the top just aren't there for me. The Rockit R-50 has clarity but is far from comfortable and doesn't take long to create listening fatigue. The DT-1350 (yes, these are on ears) provide a very tight detailed low end but don't connect me emotionally with my music. I knew something was missing so I started researching on Head Fi and other sites, the threads about custom IEMs immediately grabbed my attention, partly for the promise of better sound and partly for more comfort (surely something had to be better than comply tips). I read many reviews and called several IEM companies eventually settling on Clear Tune Monitors. Clear Tune Monitors is run out of Florida where their CIEMS are created. The head of operations is Cesar who was extremely responsive offering up a consistently satisfying customer experience such as I've rarely experienced. This in large part fuelled my decision to go with CTM (positive reviews of the CT-200 and the knowledge that I was dealing with musicians as well as competetive pricing also contributed). I was a little hesitant because there wasn't a review of the CT-500 available but I rationalized that if the dual driver CT-200 could create an impressive amount of positive reactions surely CTM would rock my world with five balanced armatures. To cut to the the chase, I was right. From the Clear Tunes web site, the details: Description CT-500 Elite:It is an exquisite monitor, utilizing a quintuple driver system and a three independent tube system. The passive crossover separates the music five ways: lows, mid-lows, mids, mid-highs, and highs. The CT-500 Elite provides the fullest range of sound with the most clarity and least amount of distortion. Specifications Acryllic shell Various Color Various ColorInput Sensitivity: 115.6 dB @ 1 kHz, 50mV Efficiency: 120.0 dB @ 1mW Freq Response: 20 Hz to 18,000 Hz Speaker : 5 precision balanced armatures drivers Impedance: 20 ohms @ 1kHzz Noise Isolation: -26dB Input connector: 1/8/in gold plug Now my take on the product itself. Build Quality: Is very, very good. The shells are smooth and finished nicely without obvious bubbles in the acryllic [pictures to be added later]. My art is less that satisfying but I believe this is largely my fault as I didn't provide an adequate source. Comfort: Straight up, for me the CT-500 are infinitely more comfortable than any other IEM I've worn. In the past I've had to remove IEMs after 3 or 4 hours as they grew increasingly less comfortable over time, often becoming irritating. I've now suffered through a very long flight with my CT-500, having them in my ears for over 7 hours at a time with no discomfort. Better still, they're easy to twist in and out allowing me to talk to the stewardess without later having to fumble and compress foam to cram my IEMS back in (I'm looking at you Etymotic with comply tips). It's like a key in a lock and if you're a frequent flier I highly recomend the experience. Isolation: Is excellent and from what I've read this is normal for CIEMS. Etymotics (and perhaps Shures with olive tips) can better the isolation of the CT-500 but at the expense of comfort. Sound Quality: I'll break it down further in additional paragraphs but lets start with 'wow!' Finally I don't feel like I'm compromising. Clarity is amazing, detail is fantastic. As an example songs with lyrics I've heard many times are suddenly clear and I've realized that I'd gotten those lyrics wrong in the past. The music is entirely coherent while remaining emotional. You can focus on one instrument or aural detail then shift your attention to another but never lose sight of the song as a whole. Clear Tune Monitors lives up to it's name. Every frequency has room to breathe and is tight and controlled not leaking into one another. For me the ultimate IEM sin is a tubby loose bass that seeps into the mids; that never happens here. Soundstage: I'll be honest with you. I've read a lot of reviews of IEMs mentioning this feature but I hadn't actually experienced it before. I'd read a paragraph about soundstage thinking: "Maybe I can't hear it because for me soundstage is about having multiple speakers in a surround setup, a stereo set of IEMs can be intimate but it can't offer detailed positional information about sounds and instruments." Suprisingly for me it can. The CT-500 presents a nicely 3D soundstage that varies in size and depth depending upon the source material. Compared to universal IEMs I've heard it's a night and day comparison. Bass: Here's where another aural bias of mine is strongly felt. Real bass can only be created by moving a lot of air. For me this is still true but with a caveat: The CT-500 creates bass that is accurate and possesses dramatic dynamics. Timbre is excellent and the bass is extremely tight but not overpowering (note I listen to a lot of EDM and trance). If you are a 'basshead' (which I define as someone who wants bass to overpower everything else) the CTM-500 are not for you. Midrange: I adore great vocals and I believe a lot of music lives in the mids. The CTM-500 sound a little forward here; again this varies from song to song but mids are always very clear and detailed while vocals (one of my favorite instruments) sound natural and carry the emotional weight I expect. Treble: This is treble done right. Everything is there without becoming fatiguing, a problem I've had when I've listened to very bright IEMs. There is air and sparkle but it's not overdone. I'm not a music producer or sound engineer. I have dabbled briefly in the field years ago taking a few courses on music production and mixing. It's obvious to me that the clarity, honesty and detail demonstrated by the CTM-500 would make them ideal monitors in a studio setting. As an audiophile looking to enjoy and get as much as possible from my music I also find the CTM-500 extremely satisfying, on par with decent speaker systems I've heard by Mirage, Paradigm, Dynaudio and KEF. Secondary Information: The music used for this review came from CDs, FLACS and 320kbps MP3s. The majority was EDM, vocal trance, techno, dance et al. But I also listened to some classical (I'm no expert) Celtic folk, Latin styles (merengue, bachata), pop, disco and movie soundtracks. Equipment used: Sansa Clip Zip: The Clip can drive the CT-500 but nowhere close to their full abilities. With no additional amplification the CT-500 sounded great out of the Clip still besting the universals I've heard. Adding a Fireye Mini amp to the chain made everything sound a lot better. Fiio E-17 Alpen: At the moment this is my best amplifier (I know, I know, I'm working on it) and the CT-500 scaled up admirably when paired with this device improving dramatically in all aspects (notably firmer bass and clearer highs). In the future I'll doubtless invest in additional amps/dacs and another custom or two. When that happens I'll try to update this review so it contains a more experienced CIEM perspective. For the moment my sole CIEM is the CT-500 and I'm very satisfied with my investment.