Hey guys, I've translated sound impressions from here (IM50&70) and here(the BA models). It is noted that the source was an AK120 for all iems. They are slightly long, so I placed them within spoiler tags. Enjoy :)
IM50 & IM70:
IM50 & IM70 (Click to show)
The IM70 has a dynamic driver like thickness to it, with an impactful midrange and bass. If anything they have 'powerful balance' (not sure how to translate that) with strong mid-range projection. On the other hand, the mids and the highs retain clarity without being overshadowed. Since both driver units are dynamic, there is no mismatch in timbre often found in hybrid designs. It supports a unique sound unlike hybrids and other dual dynamics.
Lower down the production line, the IM50 also uses dual symphonic drivers. In comparison to the IM70, it's frequency response has less 'powerfulness' (again, not quite sure how to translate this) in the mids and lows. However, this gives it a more balanced, monitor like sound, which I personally prefer. The IM50 makes it easy to understand the benefits of a dual symphonic driver, where even the lows and mids have a highly resolving quality, in addition to the highs. Although inexpensive at give or take 6000yen, it deserves attention.
As stated earlier, the 'dual symphonic drivers' use two dynamic drivers, but it is by no means developed to power up the mids and lows; rather, its intent is to provide high resolution sound.
BA Models (IM01, IM02, IM03, IM04) (Click to show)
Edited by 96rubberduckys - 10/12/13 at 8:42pm
Employing 4 BA drivers, the IM04 has a gorgeous (yes they used this exact word) sound deserving of its specifications. There is impact on the low end, and the mids/low mid are also thick and weighty. Extension in the highs are gentle while sporting a wide range.The stregnth in the mids and lows are most impressed upon the listener, with a sound that differs slightly from your typical monitor. However, 'incidental sound' (I assume this means micro details?) are plenty present. Those who look for both impact and high resolution in the same package are likely to have found their match.
The triple-driver IM03 is presented in a semi-transparent shell with a natural look. Including its price at around 40000 yen, it looks like it will be in direct competition with the SE535. It's sound has an extremely high level of completion(cohesiveness?), and while it has less impact in the lows compared to the flagship, this allows for a flatter frequency response, more monitor like and likely to be favored by many. While it is a BA iem, the highs are rich in texture, and the vocals very vivid. It has a wide sound-stage, and does not sound closed in. Succesfuly balancing price and sound quality, it is a model that warrants much attention.
The dual-BA IM02 has a refreshing quality to its sound that leans towards the treble. Without much emphasis on the mids and lows, one can appreciate the clear sounding and highly resolving qualities of BA drivers. On the other hand, those that prefer a more impactful or weightier sound should look elsewhere.
The single full range BA driver IM01 also is highly competent. It is cohesive all the way from the treble to the lows, sounding very natural without much emphasis on any frequency range. While it is a single driver, there is a quantifiable amount of bass with enough impact. Compared to the more expensive multi-driver models, its overall range is slightly narrow, and while it does have a 'cosy' (again, don't really know what the writer means) aspect, it presents a balanced neutral sound.