On my quest for the perfect sounding IEM for mobile use I came across these headphones that are rather underrepresented in the forum. The Panasonic RP-HDE10 are technically quite interesting as their 11,5mm MLF (multi-layered film) dynamic driver is actuated from both sides by a "HD Axial Dual Driver Unit" — a double set of coils and magnets. Enough proprietary tech to get me enticed...
Packaging
The RP-HDE10 come nicely presented through the transparent plastic window of a regular cardboard box. In the box is a rather voluminous hard-case with zipper, four sets of eartips (XS, S, M, L) a cable roller, and of course, the earphones. All in all, a standard packaging.
Build, quality and comfort:
In one word: spectacular! These headphones are a showcase of good industrial design. Their sandblasted housing is milled out of a single piece of aluminum, only intersected by the cylinder that contains driver unit and earpiece, and the gold plated cable connectors. All parts are seamlessly assembled and feel rock-solid. There's no company logo, and the only print are tiny L and R markers. Really, really good.Size wise, the headphones are bigger than they appear on photos, but they still fit comfortably in my average sized ears. Because there are no vent holes, isolation is above average and there is no sound leaking to the outside.
The detachable cable is quite soft and rubbery. Microphonics and wind noise are very low. This cable and the long strain relief of the L-shaped mini jack feel nicely solid and substantial, if not a little oversized, especially compared to Sony cables. Only the remote control feels a bit crude and plasticky.
All in all, these are some of the most substantial and beautifully engineered earphones I've owned. Every detail exudes "quality". No gimmicky styling, but purposeful design. Listening to the RP-HDE10, however, draws a less coherent picture.
Sound quality (with iPhone 6)
My music taste includes all kinds of electronic music (mostly house, dance and trance) as well as jazz and latin music, R&B and soul. I prefer a rather balanced sound with a solid, not overwhelming, bass fundament. And I am very sensitive to harsh or sibilant treble. That said, the RP-HDE10 feel very ambiguous. Let me explain:The HDE10 sound neutral and quite forward, with an emphasis on the mid range. There's a lush mid-bass and lower trebles are slightly elevated, yet there isn't really much depth in the instrument placing: everything is placed right in front of you, which contributes to that "flat" and "forward" sound. At the other hand, the headphones do have an excellent and sensitive detail resolution and a pretty wide soundstage, which makes them pleasant to listen to. Because of their mids-centered character, the HDE10 excel in vocals and acoustic instruments. Especially acoustic guitars or strings sound very, very good with these. So far, so good.
The caveat, however, is the lack of extension on both ends, even if Panasonic claims a wide frequency range of 3 — 50.000Hz. The trebles are less of a problem here, as I merely miss the airy feel of, say, a Sony XBA-A3. I guess the dynamic driver just can't deliver upper treble as crisp and fast as a balanced armature would do. Thus, the HDE10 sound arguably a bit congested or veiled at the upper end of the spectrum, but the trebles are smooth, and without signs of sibilance.
It's the lower end that falls short. While there is plenty of mid-bass, lower bass and sub-bass are virtually non existent. This results in a somehow lifeless presentation of anything that involves a bit of energy. Then, the HDE-10 sound a bit like "plopp-plopp" — if the bassline plays just high enough. Lower bass is simply cut off. That behavior isn't just a bummer with electronic music, but also the weight of acoustic Double bass in jazz or Latin music is severely compromised. As long as you listen to the RP-HDE10 without comparison, you probably would call this a character trait, as their general presentation is so pleasant and refined. But if you start comparing, then you'll notice the deficit.
RP-HDE10 vs. Sony XBA-A3
I'll take the XBA-A3 as a reference here, as it comes closest to the sound signature I'm after. If you're not familiar with it, here are my impressions: http://www.head-fi.org/products/sony-xba-a3/reviews/15782 Both headphones are labeled "High-Res Audio" and both sell in a roughly comparable price range.The HDE10, surprisingly, gives the A3 a run for the money in the refinement and detailing of vocals and acoustic instruments. Switching back and forth makes the mids and lower treble of the A3 actually sound almost crude and strident. Yet, the trebles of the A3 are well extended, sound livelier and more engaging overall. Switch back again, and the HDE10 suddenly sounds nasal and congested.
The bass of the A3 beats the HDE10 hands down. I'm not talking about the intensity (to some the A3 is a bass-monster), but about the linear extension of bass down to the lowest frequencies. The A3 reaches much deeper while the HDE10 really sounds cut-off. Sunscreem's "Sweet Life" sounds like a pop song, because the HDE10 completely omits the menacing bass fundament that underlies that track. The same on Al Jarreau's "Midnight Sun", where the acoustic bass is extremely faint, if non existent.
Conclusion
So, why am I loosing so many words here? Because I think the RP-HDE10 are, in some aspects, brilliant headphones. There's a lot to like about them. Yet, I am really torn between euphoria and disdain, and I think that's because they are too specialized into vocal and acoustic presentation. It really comes down to your personal preferences if you can get warm with them. If you merely listen to soft acoustic or classical music, you'll probably find them very, very exciting. If you're after an all-rounder that suits various music genres, or like a hotter tuned sound, these 'phones certainly wouldn't make you happy.
I'm traveling quite frequently, using Bose QC25 in the plane, Bluetooth connection in the car, and the in-ears in between. Therefore I don't like to fiddle around with EQ. I like it when my headphones sound good "as is", and other IEMs have already shown that they can sound exciting without EQ or amps.
That said, the RP-HDE10 sure are exciting earphones which, interestingly, are able to deliver solid low bass down to 25-20Hz, if you connect them to a sound generator. They are probably just tuned way too unexciting. There's plenty of mid-bass which somehow purveys the impression of a well-rounded sound signature. Yet, listen to the same song with other headphones and you'll note that the RP-HDE10 actually did cut off half of the bass, and thus, half of the intended atmosphere. I'd best compare it to an impression of "B&W Zeppelin vs. B&W Nautilus" (for the lack of a better description): same song, but a totally different sensation.
Yet, the RP-HDE10 do have other valuable virtues, including their supremely fine detail resolution around the mids and their overall harmonious sound signature. If you are into vocal or softer acoustic music, they are certainly worth a trial.