I like to compare IEMs based on usability and sound qualities in addition to price-range rather than just the latter. Based on this criteria, i think the Miles Davis Tributes and Sennheiser IE8 are two of it's main competitors. First, the MDs boast a similar frequency presentation & approach, differing mostly in soundstage qualities. Next competitor is the Sennheiser IE8 because it provides a bass driven sound like the DDM2s and shares the average isolation, giving it a similar usability.
These 2 IEMs are in the same price bracket, but only the MDs will be compared for practical reasons (
I only had the IE8 for a short period of time, lack notes and only remember certain qualities quite well). HJE900s will be compared because it was the only IEM I had that was remotely comparable at the time. Finally, I will compare them to the DDMs which will portray the changes made by the new model.
[Comparisons of the MD&DDM are undirect but primary benchmarks HJE900, Monster Turbine Copper (MTPC) and FA Silver Bullet were used for comparisons. This was based on technical notes and memos]
Miles Davis Tributes
These stand side by side the DDM2s both in price bracket and sound signature. These qualities alone will make it it's most direct competitor. With the MDs, the whole bass region is taken up a notch starting with the subbass and working it's way down to the midbass. The hump isn't as linear as that of the DDM2 and creates a bass that's thicker and loose. MDs still impress at not giving up much resolution from the bass to the midrange despite the added mass of thickness. The DDM2s on the other hand, are softer and more linear on the bass and there's less added warmth which results in a bit more apparent details. Compared to other leaner IEMs, both are thick in the midrange but the DDM2s are closer to a more transparent one (thought still not that close). The DDM2s actually put the midrange only a tad forward while the MDs take it up a notch. In the treble, extension and sparkle is better on the MDs but the DDM2 actually resolve the detail in a manner that's less offensive and yet a tad more revealing. Both are overall quite conservative on these regions and lack the decay, presence, and realism of cymbal crashes which reside in the treble. Presentation wise, both are intimate, but while the MDs place you in a small club, the DDM2s place you in a concert hall. Depth is similar on both but the width is larger on the DDM2s. DDM2s boot some added height despite the width that's reminiscent of the FA Silver Bullet whereas the MDs height is given by it's small setting. Imaging is similar on both, with a slight edge to the DDM2s, speed is also a tad faster on the Radius. Dynamic range is where the MDs take the cake despite a very respectable one in the DDM2s. While the DDM2s provide a very nice timbre for certain instruments, overall tonality of the MDs is better.
HJE900 [Foam modded with SA6 cables]
The now discontinuted HJE900s don't slack far behind the TWF21 despite the price difference and they each trade out many strengths and weaknesses. As a whole the bass of the TWF21 has a lot more going for it as it extends a bit deeper and is more linear throughout the range. The HJE900s are more grounded on the midbass but at least provide a bit more speed while maintaining a nice decay. There is more added warmth to the midrange in the HJE900s and the midrange presence is laid back compared to the Radius. Despite added warmth on the HJE900s, the higher midrange is edgier, with more "crunch" and it gets you ready for the treble presentation. Presence of the treble is more apparent on the HJE900s but is prone to harshness because of a hump from that starts ~4k and resolves at ~8k. This is fortunately tamed by doing a foam mod (adding foam to the nozzle). Treble extension is actually a bit better on the DDM2s but cymbal crashes actually sound more realistic on the Panasonics because it has the proper presence and sparkle. With the SA6 cable the presentation of the HJE900's soundstage is smaller than the stock configuration but it gains slightly more apparent imaging. Compared to the DDM2s, the Radius' stage is simply bigger (airer, wider and deeper). The overall presentation is more impressive but it does have a bit less precise imaging than the Panasonics. Speed is faster on the HJE900s but dynamic range is larger on the DDM2s. To note, the HJE900s have a tonality that noticeably exceeds that of the DDM2. In general the HJE900s are more compatable to more instruments than the DDM2s in terms of tonality.
TWF11R (DDM)
So what are the changes from the first Radius (DDM)? First, it is noticeably softer on the bass whereas the DDM has more presence and midrange warmth. Lower midrange is more apparent on the DDMs but the DDM2s give you a finesse as it's more refined. Treble presence is a bit more on the DDM2s but you also get a sense of details as you go further down (better extension). Presentation is where I see the most changes as it is more coherent on the DDM2s. The DDMs give you a soundstage that can sound very tinny at times and grand at others. With the DDMs, depth and width are contrasted by the intimacy of the midrange in a more contrasting matter than the DDM2. This was a result of the DDMs depth but also to it's endless width at times. The DDM2s actually put things together more concisely into a general box (though still wide) whereas the DDMs are more polarizing in imaging and slightly more blended. Dynamic range is larger on the DDM by a notch and the DDM2s are a tiny bit faster.


There is an improved balance in the W2 (DDM2)
Conclusion
In my opinion, the big Japanese companies make the best high-end dynamic IEMs that are also complemented by oustanding build quality. Radius on the other hand seem to be slightly behind as the company is still trying to grow. With the TWF21 they seem to be taking some steps forward with the DDM2s, but unfortunately also took steps back in other areas. First of all, while the sound is improved from the DDMs, I don't see it having the appeal the first incarnation had. The DDMs were released at a good time because the competition wasn't as fierce and it had a low price to boot. For the price of ~160$ the DDMs were the best sounding dynamic for the price. That kind of value allowed users to overlook the poor build, isolation and comfort aspects. With the DDM2s priced at the ~250$ price range, there is going to be more hesitation considering the overall package outside of sound quality. The build, isolation and fit is inferior to that of the MDs and IE8s (main competitors). Likewise, the FX500 and EX600 that have comparable isolation are technically on par and yet cheaper in price. Luckily DDM2s do have a different signature than the FX500/EX600s and compared to the MDs and IE8s it is slightly more balanced and technically proficient. They are therefore unique enough to satisfy a specific need, but their pricing will hold them back on mass appeal.
Open Letter to Radius
Being a Japanese company, it will be very hard to communicate with such a company due to language barrier. Neverthless, I will be simulating my feedback to Radius in the following passage.
Dear Radius
I recently had a nice 2 week experience with the newly released DDM2s and have lot's thoughs in regards to how they stand in the US market. The DDM2s improve the comfort and sound of the DDM1 but I am questioning it's pricing and see room for improvement if you want the same popularity of the first. Compared to the DDMs, the build is of exactly the same quality and the drivers seem to be apparently the same. The newer shell design and improved response is welcomed but I am afraid that it isn't enough to place them with other competitors in that price-range. I personally think bigger improvements could've been made to justifice the newer price. First, the previous cable of the DDM wasn't improved and it ruins the practicality of the IEM. IEMs are for portable use and the touch of the cable produces too much noise that detracts in movement (a shirt clip will also be highly welcomed). Second, the housing is made of plastic while other competing dynamic IEMs of the same or similar price range are using better materials, examples are the EX600, CKM99, Miles Davis Tribute, FX500, etc. With a material such as Aluminum, you can have better resonance response and yet maintain that lightweight practicality. In addition to the l-plug adapter, you guys could add a channel switching adapter that enables the user to wear them in an over the ear fashion, helping the cable noise and comfort. Disappointed in the tips, a variety of improved tips should be provided and could consider designs such as these. Lastly, it will be interesting to know the diaphragm material as it's usually published in other Japanese dynamic driver IEMs. Perhaps experimenting with different materials could prove useful for the next flagship. You guys have been innovative with the driver design, but I feel that the practicality of the IEM could still be improved. I understand that you guys are a growing, small company and I hope for some consideration of the presented suggestions. I want to thank you for your time and will look forward to your next flagship IEM.
regards
Inks
Final Thank-Yous
Joker, for choosing me for the loan program.
Dimitri for the generosity of loaning out this pair.
And..all the users who have personally asked for advice. You guys have inspired me to write this review and a possible "buying-guide" thread.