Spoiler TLDR: A sound that can be used for wide range of music, but not bass head. Slightly warm and natural sounding. Quick and detailed, circular soundstage, but not huge width.
Disclamer: These iem were purchased with my own cash while on vacation in Tokyo. I am not associated with Radius or any company for that matter, including the links in the review. This review is my personal unbiased opinion and keep in mind that these iem are
10 months old. I want to thank Head-Fi, for giving the forum to learn and express. Enjoy.
Introduction: What makes someone wake up early morning while on vacation in order to leave their family in an AirBnB, cross tokyo, and purchase an iem. Even more so, in a Yodobashi electronics store that has rows and rows of iem, why the TWF-31.
The answer is of course Music.
Radius, the developer of these was founded in 1996. Taken from their website they develop "Accessories for Apple devices and other Information technology products, Headohones, and Audio products". They have various iem developed over the years, a lightning dac and even bluetooth products now.
http://www.radius.co.jp/en_product/hp-twf31/
A little about myself. I am a lover of japanese related things in general. From History, style, food, cars, and of course electronics. I got tired of the bloated, no detail, low quality build iems in the local stores and started looking into japanese brands. I came across this little guy below, curtesy of
https://clarityfidelity.blogspot.com/?m=1, and had to check them out.
Packaging and Accessories:
The packaging could be described as above standard, but not totl. There is an outer cardboard box with an image of the iem on the front and technical description on the back. Inside another cardboard box where the top slides up to expose the iems and company slogan. The portion directly above the iem has a piece of soft cloth making it even harder for the iem to get damaged in shipping. All lettering is elegant gold on black, same as the iem themselves. Below that is the domed compartment which houses the accessories which would be considered standard fair nowadays. A clamshell case, 4 pairs of custom Radius tips and small booklet.
The clamshell is soft cloth on the inside and a hard outside with a kind of stitched leather. I myself am not a fan of clamshells but this one is large enough to fit the TWF31 without coiling that tight. It also still fits in my pocket. Recently decided to use the hard plastic round case that came with my VE iems to keep the TWF31 inside.
Aside from the thought put into the iem themselves, Radius made some changes to the eartips. As you might be able to tell in the photo. The eartips are larger towards the opening and narrow down into the back. This gives a better seal with shallow insertion compared to regular single flange silicon/rubber tips. Despite trying a variety of tips, comply, symbiot, large and small bore tips, I always go back to the original mediums.
Build and Fitment:
When it comes to fitment, I consider these very comfortable. The iem give 2 depths for the tips to be placed allowing for a shallow, or standard insertion. Even if I was to pull my ear back and insert them deeper with smaller tips the housing doesn’t press on the ears. There are no hot spots, and I can wear them for hours without adjustment. Both the included cable which can be changed (stardard mmcx) are ligh weight, so they do not fall out easily with head movement despite shallow fitment. The iem are intended to be worn down, but if you switch L & R, they can be worn over ear. Which is good because one of my grips with them is the cable.
As mentioned the cable is light weight, but thin and microphonic. It is covered in a cloth with decent quality plastic neck tie. It resist tangle pretty good, and ends in a 45deg 3.5mm SE connector. No microphone but both strain reliefs on the mmcx and 3.5mm side are well done. There are L & R markings on both the housings and both mmcx connectors.
The housings are a combination of smooth plastic, textured plastic and gold (colored?) aluminum. There is a lot of detail put into the texturing on both the housing and the connector.
There is a seam where the different meet, but over the months I have seen no fatigue or flex. Perhaps if you were to step on them or fall from high up but multiple tip changes, removing cables, accidentally getting caught on something and yanked out posed no issues.
Now the sound:
All songs used were in 16/44.1 flac with a couple listed below. The included medium tips and HTC were used for its lowest output impedance and small bore.
Beethoven Opus 49 No.2 (Lifescapes Album 1996)
Mighty Mighty Bostones – Someday I Suppose
Metallica - blackened
MJ - Bad
MJ - PYT
Soundstage:
I will try to describe the shape of the sound stage and where you sit in the audience. There more space in front and above than below and behind. I have heard sounds circle just outside around my head, but you don’t find yourself looking behind to make sure it’s the music and not a person standing there. There could be a bit more width, but the height and depth make up for it. Layering is good because of that and instrument separation is well done. When listening to band its almost as if you are a couple rows away from the stage with the singer up front but not in your face. The drums a little deeper back and the guitars nicely diagonal. In Bohemian Rhapsody you can easily pick out all the different sounds. In lifescapes Beethoven you can hear the piano keys as if you are sitting there. Every note moving closer and farther from front center to the right for high notes and left for low.
Tip Rolling:
I am an avid tip roller because I believe they can sculpt the sound to you liking, with these though I suggest keeping the included tips. Partly because the shape and partly the small bore. The small bore tips seem to keep the bass a little elevated compared to neutral. I feel this is a good match for the sound signature. YMMV. If you rather comply will work fine also, but I feel it attenuates the sound some. The TS500 fit. Another option I feel is good is a medium bore silicone and use the shorter stem seating. Moving the tip to the shorter seat gives added sub bass, and the medium bore reduces the mid bass while adding a little treble.
Edit: I added some info above because I wanted to rephrase and expand on the tips some.
Lows:
The lows are very even, and speed of the mid and upper bass is very quick in my opinion. This is not a bass head iem, but gives a controlled and just slightly recessed sound. No bloat or bleed into the lower mids. Due to the coming strictly from the dd I feel they are little less spacious, but not claustrophobic feeling. Using a basic youtube freq sweep I hear just below 30hz. Probably given the right song 20-25hz could be felt/heard.
Drums:
Bass kicks are tight and double peddles are clean. Snare hits, wire brush and snare wires are nicely detailed. The attack is a bit strong, but sounds natural to me. Best in my opinion are toms with a nice boom, but not bloat. Again natural and well separated.
Vocals:
Very clear vocals and articulate. I would say a little better for female vocals which give me tingles on the back of my neck. Nhora, Adele, Alicia Keys are all clear and up front. Male vocals, Ed Sheeran, Mos Def, BB King are still good but sometimes get mixed depth wise with the instruments.
Highs:
The highs are detailed and without any harshness. They expand slightly further than the lows and extend well frequency wise. Cymbals have a nice sizzle and songs like MJs Bad give a good volume without being sibilant.
Sources:
The TWF31 are fairly easy to drive. I never use EQ in order to enjoy the signature of the items. Using my HTC 10 I don’t need more than half volume to be at a good listening volume. Normally I leave it at 1/3. Again with the ipod classic 160Gb(6th gen) it takes the same. With the Sound blaster ZX on my desktop it only needs 1/4.
In order to compare between the three, I used Mighty Mighty Bostones. I believe the HTC has the lowest impedence, the ipod is supposed to have in the teens range, and the SB ZX is 30ohm (at least that’s what I read). The SB gives more bass, all three give even mids, but the bass from the SB over powers the mids some. Also the ipod has a sharper high hat, and snares, including less bass guitar.
Conclusions:
If you want something elegant looking, for use while sitting down or over ear while doing stuff in a semi quiet area. Nice natural sound that can go from casual to fairly quick and complicated music then put these on your list.
