Thanks again to RHA for the sample set.
History: RHA is based out of the United Kingdom and is a division of Reid Heath Ltd. RHA products are born in the research and development laboratories in Glasgow, Scotland. Due to the fact the U.S. is a new market for RHA, all RHA products are being offered exclusively through the Apple Store at this time. International customers can order from the RHA website.
Here are some more detailed photos to kick off the review:


Build: As you can see from the photographs, the build quality of the MA450i is quite good. The dynamic drivers are 10mm mylar. The housing for each driver consists of a plastic backing and an aluminum bell. The aluminum bell is purposely designed to be like the bell of a trumpet and is inverted to funnel sound directly into the ear canal. I know that last part sounds cheezy, but it seems to be working. The design of the eartips is the best I've seen. The single flange "orange-bore" tips are wonderful because the orange sound tube is sturdy and seems to be denser and stronger than the outer flange. Due to this reinforced sound tube, I am able to really push the tips around to get a good fit without mashing the tip into the side of the ear canal and closing the front of the tip. I like to use the smallest of the orange-bore tips because they just pop-in and fit right. The package also comes with bi-flanges and five other single flange tips, a carrying case, tip-holder case, and instruction booklet.
The cable and iPhone controls are nice and well built. The cable is fabric and microphonic. On the other hand, the fabric cable never tangles and always lays flat. Therefore, I always wear the cable over-the-ear and use the chin slider. The strain reliefs and Y-split also seem to be very sturdy; but if not, RHA offers a 3-year warranty! One thing for me: I really wish these came with a shirt clip. A shirt clip would be good.
Fit: I really like the fit on these. The housings are very small. The tips disappear into my ear canal and the outer housing fits neatly behind and inside the tragus. Isolation is very good: when I'm fitting the 'phones the seal becomes obvious when outside noises are suddenly attenuated to almost nothing. Of course, YMMV, and I have never used custom iems.
Bass: The bass on these earphones is simply fantastic. The sound has a nice blend of mid-bass and sub-bass. The dynamic driver and aluminum bell push a decent amount of air; there is more air than a sealed iem like the M6 but better control and depth compared to vented designs like the Apple EarPods. What I mean by air in this sense is the perceived impact and weight of the bass: the feeling that the air has weight. The bass is warm and well extended. Compared to the EarPods that came with my iPhone 5, the MA450i has almost no mid-bass boost and much better sub-bass. As I mentioned in an earlier post: these 'phones really rock with electronic bass.
Midrange: The midrange is smooth, warm, and detailed. Strings and vocals sound wonderful. The ability of the driver to push air is very interesting in the midrange. Guitars have impact and the plucking of the strings can be felt on some tracks. Due to the warm tuning of the iem, there seems to be more detail in the midrange than in the treble. It's a very interesting phenomena for my brain because I feel like the laid back sound should just be warm and fluffy sounding, but the detail and resolution are actually very good. All the sounds are present and accounted for, just more so in the midrange than anywhere else.
Treble: The treble is laid back. If you want treble brightness this probably isn't the 'phone for you. I find the treble to be pleasant and I still hear all the cymbals and synthesizers and sounds that I'm supposed to be hearing. However, the treble is noticeably quieter in relation to the rest of the sound signature. It seems like there's a nice bump in the upper-mids and then the treble rolls off in a very gradual but continual slope that fades into the distance. As I said, I find it to be very pleasant. Combined with the best fit I've found in an iem, the treble makes for long, non-fatiguing listening sessions.
Presentation: The MA450i excels at presenting a warm and well-integrated sound. The headstage is not as large as I have heard; however, the warmth and detail in the midrange make for a nice engaging experience. These 'phones also have very good dynamic range and the left-right separation is present, but not huge or wide.
Conclusion: If you like bright treble, or don't like fabric cables, these earphones really aren't for you. The MA450i really excels at presenting a warm-yet-detailed sound that is engaging and pleasant. The headstage is average but very integrated. These earphones should be a great workhorse for anyone looking for solid iPhone controls and a solid, warm sound signature that still has detail.
I will be posting updates as time goes on. I reserve the right to change my opinion.
http://www.rha-audio.com/us/earphones/ma450i-black.html - product info
http://store.apple.com/us/product/H8965ZM/A/rha-ma450i-noise-isolating-in-ear-headphones-with-mic - Apple product page
Edited by iPhone IEM - 12/19/12 at 11:17pm