Rhapsodio RDB+ Hybrid (2BA + Dynamic driver)

[size=12.0pt]Before writing this review, I would like to thank Charles for generously sending out multiple IEMs and amplifiers for us to try and review. Charles is also one of the friendliest and most responsive guys that I have met in the audio world and often responds to emails in a few minutes. This is something that I take into account when buying any product, especially one at this price. I am in no way affiliated with nor against Rhapsodio in any way so these are my own, unbiased opinions on the Rhapsodio RDB v1 IEM.[/size]
 
[size=20.0pt]Introduction[/size]
[size=12.0pt]Rhapsodio is a relatively new company to the audio world and they’ve already caused quite a stir on Head-Fi with their interesting products which have been compared to much more expensive ones. For example, swimsonny thinks their $400 R^2 has been said to compete very well against the $1300 Tralucent 1plus2, even winning in some aspects. But this IEM that I will be reviewing is the more expensive model, the RDB v1 priced at $US650 not including fancy cable upgrades. It uses a TWFK driver for the midrange and treble and an 8mm dynamic driver for the bass. To my knowledge, there was another similar model, the RDB+ v1 (which has now been discontinued?) which uses a 10mm dynamic driver but I haven’t heard that one so I can’t provide any comparisons. The reviews from H20Fidelity, mrAdrian and svyr are of the previous version. [/size]
 
[size=20.0pt]Testing Gear[/size]
[size=12.0pt]All testing was made with my HDP-R10, my Sansa Clip+, Samsung Galaxy S3, K2 amp and Shozy amp. First off, I want to make it clear that this is not very source dependant, well not as much as my UM Miracles anyway. They do not need to be amped and there is not as much difference between my Sansa Clip+ and my HDP-R10 as you would expect since the HDP-R10 costs 30x as much as my Clip+. However, a better source does help make the sound better. For example, if the sound from my HDP-R10 was 100%, the Clip+ would be 70-80%. [/size]
 
[size=20.0pt]Accessories[/size]
[size=12.0pt]I don’t know what it comes with if you bought it, but I think that it comes with 3 pairs of silicone tips and a pair of foam tips along with an Otterbox (2000?) case which is waterproof and crushproof. It’s pretty much the same as a Pelican case if you’ve used one of those. My demo version also came with a large metal case with “Rhapsodio” written on it which IMO is unnecessary but a nice addition. Good, but I would have liked to see it come with some extra tips; I don’t mind the fact that there is no IEM cleaner because there is a filter that stops ear wax from going into the IEM. [/size]


 
 
[size=20.0pt]Isolation, Design & Cable[/size]
[size=12.0pt]Being a vented IEM, isolation is not one of its strong point. Most IEMs that I have heard do isolate much better than these. The degree of isolation is about the level of IE8(0), Sony EX1000 and some other dynamic driver IEMs which need a vent to breathe. As for the design, you can customise the colour of the body and faceplates. The faceplates can be carbon fibre black or silver and the body can be any colour I think. What is interesting is that if you look closely at the drivers of the IEM, you will see that the TWFK drivers are actually inserted into your ear full as they are at the tip of the IEM.
I’m not sure what cable it comes with if you order the most basic IEM with no upgrades, but I got a really well built brown clothed cable that Charles said was copper and silver crystals whatever that means. The braiding was very consistent and didn’t have different sized gaps. While it was quite thick, it was still very easy to use. Microphonics is worse than normal stock CIEM cables, but being a couple of times thicker, this is hardly a surprise.  It was the best sounding and easiest cable to use out of the 3 cables that I received even though it was the thickest. I think that this cable is able to be purchased directly from Charles for $160. The first pic is of the old version, the second pic is the RDB v1 next to my full sized customs and the last one is the RDB 2v1 on the left and the RDB v1 on the right. [/size]

 
 
 
 
[size=20.0pt]Sound Quality[/size]
[size=12.0pt]Sorry if I have bored you with all of that, but now we are finally at the meat of the review – the sound. I will be breaking this part into a few sections like in my previous reviews and as you will soon see, (spoiler alert) I really like this IEM. However, if you are looking for an analytical IEM, this is not for you. [/size]
 
[size=18.0pt]Bass[/size]
[size=12.0pt]I’m not sure if this is true, but someone mentioned that RDB stood for really dynamic bass. I really do agree with this statement since the bass is certainly more forward than one of a neutral IEM, but it doesn’t always sound like a dynamic driver. Personally, I have always been on the BA side of the balanced armature or dynamic driver debate, but I must say that this dynamic driver has the control of a BA driver, but also has the rumble of a dynamic driver when the song calls for it. The bass rumble is exceptional, but sometimes I think that it is just a tad bit too much, drowning out some micro details. Bass extension is superb and there is no bleed into the midrange. To sum up, bass on the RDB v1 is exceptional and it was certainly the first thing that hit me when I listened to them. [/size]
 
[size=18.0pt]Midrange[/size]
[size=12.0pt]I must say that the mids are really a love or hate thing. They have this texture that sometimes makes vocals very enjoyable to listen to, but can also seem a bit thin on certain tracks. When I first listened to it, my first thought was that the mids were too thin like the RDB 2v1, but after using it for a while, I realised that they were not as lush as those of my Miracles, but still extremely enjoyable. It is also worth mentioning that the mids are recessed due to the bass and treble being more upfront. As a result, on a few tracks in my collection sounded a bit off. I wouldn’t sound bad, but I enjoyed those of the Miracles and AKG K3003 more. I did like the mids on some songs, but other sounded a bit odd. The Miracles are much more solid and present everything in a more polite manner and it is much harder to fault them. [/size]
 
[size=18.0pt]Treble[/size]
[size=12.0pt]I can’t decide which part of this earphone I like the best – the bass or the treble. Both sections were extremely fun for me. As I mentioned in my UM Miracle review, I would have loved to have a bit more sparkle without it going overboard and the RDB v1 almost gets it right. It is maybe 1 or 2 db off, being slightly too bright for me. There is slight sibilance but treble detail more than makes up for that. Going from the Miracles to this makes this seem bright and harsh and going from these to the Miracles makes the Miracles seem like there is a slight veil. The cymbals sound a tad harsh, but that is actually what they sound like and if you have gone to hear a band or play in one, you will know what I mean. [/size]
 
[size=20.0pt]Presentation[/size]
[size=12.0pt]I have read all about the Tralucent 1plus2 and just recently found out that the original RDB+ v1 and the 1plus2 v1 used the same drivers. These are exactly what I read on the 1plus2, but maybe a bit worse. The soundstage is large for an IEM, but not huge and it a bit smaller than the UM Miracles. The RDB v1 also makes music sound like there is a stage in front of you instead of a surround feeling like the Miracles. I actually prefer the RDB v1’s presentation over the Miracles since it is more realistic.[/size]
 
[size=20.0pt]Accuracy[/size]
[size=12.0pt]I personally perceive accuracy as how similar it sounds to a live presentation and I’m glad to say that the RDB v1 has done exceptionally for a sub $1000 IEM. The reproduce instruments extremely well but there is quite a bit of colouration to the sound. This does make the sound more fun but it is certainly not for one who craves accuracy. [/size]
 
[size=20.0pt]Imaging and Soundstage[/size]
[size=12.0pt]As mentioned above, the soundstage is very good for an IEM, but not the best that I have heard in an IEM. I just feel like the soundstage of the Miracles and the IE8s are slightly bigger.
The imaging however, is the best that I have heard from an IEM. It is very slightly better than the Miracles because the imaging is more exact and the stage is in front of you rather than around you. [/size]
 
[size=20.0pt]Instrument Separation[/size]
[size=12.0pt]This puts every IEM that I have heard under $1000 to shame. Everything is so coherent yet you can hear each layer of the music without even trying to. With the Brainwavz B2s, a TWFK driver based IEM, the separation is miles behind this and just cannot match it in any way. On congested tracks, this really does let some instruments shine through or make some things easier to hear. However, it is not the last word in instrument separation and my UM Miracle is better in this area and the K3003 is as well, but only very slightly. [/size]
 
[size=20.0pt]Details[/size]
[size=12.0pt]This certainly does have a lot of detail, but due to the bass, the details are sometimes a bit hard to make out and some micro details are left out altogether. This is not completely a bad thing since it is much more forgiving of badly mastered tracks than many other IEMs. For example, “Hall of Fame” is truly hard to listen to using my Miracles, but it is still very enjoyable with these. [/size]
 
[size=20.0pt]Summary[/size]
[size=12.0pt]Rhapsodio have created a world class IEM that they could have very easily priced at $800-$1200 but they have decided to price it at $650. This is not to be interpreted as low worth but is actually high value. I recommend this to anyone who likes a fun sound signature who has less than $1000 to spend and doesn’t mind the low level of isolation. [/size]
[size=small]Edit: changed to 4 star because of Rhapsodio's QC problems and their unresponsiveness. [/size]

Introduction

 

The Rhapsodio RDB+ 2v1 (formerly known as RDP+ v2) is the baby brother of the RDB+ v1. It's still a 2xBA & 1xDD but instead of a 10mm driver that the older brother has, it sports an 8mm driver instead. As such the overall shell of the RDB+ 2v1 is smaller. In addition, the sound of the RDB+ 2v1 isn't necessarily a successor of the RDB+ v1. Talking to the makers, the RDB+ 2v1 is meant to have a more accurate sound signature, a goal of which I feel they have achieved.
 

[size=1.5em] Design & Ergonomics[/size]

As can be seen, this isn't a very big IEM. Used with Ortofon tips, it fits snugly and comfortably in my ears and don't protrude out that much. Despite movement from walking or head motion, the IEM sits in place in the ear. Unlike the RDB+ v1, the bass port is placed next to the cable socket instead. At least for my ears, the port doesn't get blocked. However the IEM is prone to wind noise especially in a wind tunnel situation (subway exits, etc.). On normal days though, isolation is decent. I can hear external ambient noise however are easily ignored and not distracting when music starts playing.
 

The construction material is the same as other IEMs and seem durable although it seems more recently it's been revised with an even more robust shell. Note also the goove in the nozzle seems to hold the tips reasonably well. Having said that, My Ortofon tip has fallen off twice early on but haven't fallen out recently.

[size=1.5em]  [/size]

[size=1.5em] Sensitivity[/size]

The RDB+ 2v1 is an easy-to-drive IEM which is easily driven by an iPhone or other mobile device. It doesn't require an external amp, however one still can be used to suit the listener's signature preferences. Although not particularly sensitive to hiss, it is sensitive to poorly mastered recordings however not necessarily sensitive especially with live recordings. However, I've not encountered any issues with poorly ripped tracks.

[size=1.5em]  [/size]

[size=1.5em] Sound Signature[/size]

Tests were all done with the Ortofon tips. Overall, as mentioned in the introduction, I find these IEMs to fulfill it's designers' objectives. The signature is almost somewhat neutral. I'd venture to say that, as per the maker, mostly accurate too. The reason why I mentioned mostly is that occasionally, I find the upper bass/lower mids to be just a tad lacking but not by much. Usually the other positive features of the signature distracts from noticing that lacking point.

[size=1.17em]  [/size]

[size=1.17em] Treble[/size]

I never realised until recently that I'm particularly sensitive to bright trebles. This is coming from someone who used to enjoy the Edition 8's and owned one for 9 months! As such with the RDB+ 2v1, I find the trebles to be sitting on the fence really depending on how the wind blows. Given the right conditions (cable, amp, DAC), it has a very airy and smooth presentation - one of the highlights of the IEM in fact. However with a bright amp + pure silver cables + bright musical tracks, then the trebles could sound harsh. However I don't actually encounter that latter combination that much which means most of the time I'm actually enjoying the airy trebles quite a bit. I also suspect that the mids have a big part at play to the relative perception of the trebles (which is why I may not find the trebles sibilant most of the time).

[size=1.17em]  [/size]

[size=1.17em] Midrange[/size]

To my ears the mids are also quite flat except for the lower end where I personally feel it takes a little bit of a dip but not by much. In fact due to the rest of the frequency and the airy trebles, I actually don't notice it most of the time. Vocals sound detailed yet rich and musical. In fact vocal tracks seem to shine with this IEM's signature. Listening to the Norah Jones' Come Away With Me album, there's a lush richness in her voice with an intimate presentation. Listening to Taylor Swift's "Ours" and vocals are great whilst guitars to be quite crystal clear. Similarly with A1's When I'm Missing You, the vocals & guitar at the introduction is quite musical. With Adele's 21 album (possibly more particularly to the "Set Fire To The Rain" track, I personally could do with a little more upper bass/lower mids emphasis. However it's ever so slight that the other positive features of the signature seem to distract me from noticing this little dip.

[size=1.17em]  [/size]

[size=1.17em] Bass[/size]

The bass is an area where I think most listeners will perceive this IEM to be lacking. However what I find rather interesting about the bass is that most of the times when it's truly called for it's there, but's just not forwardly present all the time. Back to the Taylor Swift's track, the bass there fills nicely without being overpowering. However with the A1 track, although the bass is tight, the sub-bass does feel somewhat lacking, therefore lacking the fun-factor too.

[size=1.17em]  [/size]

[size=1.17em] Soundstage and Imaging[/size]

The soundstage is decent. These days with the likes of FitEar MH335DW or Tralucent 1Plus2 with their supermassive soundstage, the average IEM's pale by comparison. Having said that, it doesn't sound congested by my standards at least. But not exactly super vast either. I feel it performs well amongst its peers. The imaging on the other hand is another forte of the RDB+ 2v1. This is more prevalent with album's such as "This is Chris Botti" with the live recordings.

[size=1.17em]  [/size]

[size=1.17em] Airy Presentation, Timbre, & Speed Response[/size]

I'm probably repeating the airy presentation again however this is one of the great features in addition to timbre that stick to my mind. String instruments such as violins or acoustic guitars, and percussions just sound so natural with this IEM. I feel they are presented crystal clear and accurate. The response of the IEM also sounds quite fast. Listening to Cher Lloyd's Sticks + Stones album, the tracks don't sound slow at all and keep up pretty well.

[size=1.5em]  [/size]

[size=1.5em] Summary[/size]

Overall to my ears, these IEMs are as what the maker has told me - accurate. To me they also sound mostly neutral of which I'd love to compare them to the UERM one day. They don't have a warm signature, nor are these bassy or hi-fi fun sounding IEMs and if a prospective buyer is looking for those kinds of signature, I'd have to politely recommend looking elsewhere. However if one is looking for a mostly neutral IEM, to my ears they're closer towards being the "monitor" styled signatures - at least tonally. Finally but not least for the price I paid, they are extremely great value for money.

Rhapsodio RDB+ Hybrid:
 

Is it named after Rhapsodio's Dynamic BA, or for its Really Dynamic Bass?!
 
Disclaimer:
Rhapsodio's RDB+ is a really fantastic sounding IEM, the best IEM I have heard actually. However I do not have a lot of iem's as I am more of a headphone headfier. Hence in my review I will focus on the sonic performance of the RDB+ instead of any comparisons unless requested.
Most listening are done by my Sflo:2 LO -> TTVJ Slim, critical judgement from my NFB5.2 and casually from my iPod 3rd gen.
 
Build Quality, Comfort, Sound isolation etc.
To cut it short, very comfortable, better isolation compared to what I own (GR07, TF10), and maybe Rhapsodio could work on the Build quality e.g. the finish, bubbles inside the shell etc a bit more to let the aesthetics match up with its grande sound.
 

 
Sound: Bottom up!
 
The BASS of the RDB+ is certainly the first thing that caught my attention, in fact it stunned me at maybe the first second of my listening! It was something I have never experienced: a very dynamic, clean but generous amount of bass. Quality is absolutely satisfying, VERY close but not as deep extending as the Denon D5000 - but it is a lot cleaner! While some say the Denon has muddy bass or a slower bass response, the RDB+ is nothing like that. Very quick responses, when the song calls for it the bass punches you miles away, and in a split second it feels like nothing has happened, only I was left there thinking what just happened! It is very amazing to listen to such high quality and quantity of bass in such a tiny pair of in ears, very glad for the review and experience!
 
The MIDS of the RDB+ however is a little bit too recessed for me. Given my headphone selection (AKG K400, Alessandro MSPro, Senn HD580 etc) and my music preference, the RDB+ is just lacking that little bit of forwardness/aggressive mid sound for them to truly grab my heart. This mainly occur at guitars and male vocals --> meaning the lower mids IF I am correct. I think that is where the Dynamic driver and the TWFK crossover occurs, but by all means ask Rhapdsodio instead of trusting me. I have to mention this because one day at work I decided to listen to some Hikaru Utada on my laptop -> UD100 -> TTVJ Setup and it was very very good. To my surprise there was actually a lot of emotions in her voice which I did not expect when I was auditing these with Eric Clapton/RHCP/other rock music. To me I much prefer the mids on the Alessandro's where the guitar shouts for attention. On the RDB+, the dynamic bass overshines the mids which is not my best preference.
 
The TREBLE is good, very detailed, and balances the bass presence well. It avoids the sound signature turning into a blackhole with too much bass, by adding that clarity and brightness to the mix. Now I actually think it is normal to have the lower mids slightly recessed due to the brilliant treble and seductive bass tuning. Svyr can be my witness, because I actually pm'd him to confirm if the BA is a TWFK because what I read about iems like the DBA02, UE700 and GR01 matches my sonic impression of the RDB+'s treble.
 
Other notes:
DETAIL detail is unbelievably well presented in these little monitors! And that is across the whole frequency response from Bass to Treble! GREAT JOB in tuning and choosing the right drivers, Rhapdsodio!
 
TRANSPARENCY, CLARITY I can not describe just how amazing it gets when the dynamic bass driver mates the TWFK. The IEM avoids being too dark nor too bright, yet sound has weight and air, all in one very satisfying package.
 
Conclusion: It is all about the BALANCE
 

 
The RDB+ overall is so nicely balanced that it has many things in the right quality and quantity, only except (slightly) the mids unfortunately.  It has the good qualities of a dynamic driver iem, where the bass is visceral and pushes a lot of air, punches into your eardrums. It also has a lot of delicacy in its mids and treble, you can hear it from the amazing details and clarity in the overall tone (even with the great quantity of bass) like the good things you hear about the famous TWFK. If only they could give a bit more bite at the midrange - electric guitar distortions! - the RDB+ would have really tempted me to re-build my portable setup and I might even sell a few headphones to fund them!

Rhapdsodio RDB+ vs some current hybrid IEMs.

Rhapsodio sent us some gear for the Sydney 2013 Jan meet/to review after.
The review skims over some gear used, what I look for in IEM sound [in case it's not what you look for ] a bit of info about Rhapsodio itself, and general/quick info about RDB+, before going into detail, so skip as appropriate if you're not in a reading mood
It also includes some musings on accumulated experiences of using custom universals for about a year now, so if you're not into that - my apologies.
Likewise, please excuse the the poor pic quality - the ones not supplied by Rhapsodio mostly turned out bad - new camera/last minute pics. [and no appropriate composition or interesting backdrops ]

Gear:

Source: Musiland MD11/MD30 [DAC only], Clip+ [into amps].
Amps: Epiphany Acoustics EPH-O2, Clip+ (as an amp), P&D Amp-k Pro
Cables: misc fancy looking interconnect, 2 cables supplied by Rhapsodio - silver + viablue , and flat weave 4 conductor per channel one + mini Oyaide .
Other IEMs/Headphones: Audiofly AF78, T-PEOS H-100, Unique Melody (UM) (custom universal versions): Merlin, may mention CI+TWFK . Keep in mind, officially Unique Melody don't really recommend getting their universals, that said the universal mold I have is the same one they use for demo Merlins (they also have a couple of other ones - without a helix lock with different nozzle diameters )
Quick impressions from Sydney meet: Sennheisser HD800/Beyer T1

Burn-in:

pretty sure the IEM was used prior to being shipped to me. I used it for 2.5 weeks, several hours a day on some days, so probably around 100h+. Everything else was extensively used prior. All the sources/amps were pre-warmed for 5 mins to get to normal operating temp.
Volume matching: To a comfortable level by ear

General sound preference [this is what I'm looking for in an IEM or HP]:

Forward lower mids - around 1-3k, preferrably not too much. But still relatively enough 3-5k sparkle. Extended and relatively forward bass. Crisp, extended but not sibilant highs. To give you an indication - I probably think Beyer T1 levels of bass or HD800 on a suitable amp are realistic/necessary (the kind where you go to a piano concerto, and the drummer is relatively enthusiatic and piano sounds full enough). This all has to sound coherent enough as a package.

A bit about rhapsodio:

Some background and contact info is below
Site: http://rhapsodio-cmw.com
FB: http://www.facebook.com/pages/Rhapsodio/254838767959521
email: rhapsodiohk [AT] gmail.com [Sammy and Charles]
Some products: Cables, Universal Customs [acrylic universals], Balanced armature/Dynamic driver IEMs in various configurations. Upcoming 3BA+DD, 3+BA Resellers to amps, IEMs, DYI kits
Some general info: 'Rhapsodio was founded in 2011, and has been providing exclusive and quality DIY kits, handcrafted cables and custom monitors to the public ever since. Located in Mong Kok, Hong Kong'
'Our aim is to offer some high quality but budget products that already exist, also some unique and exclusive products from us or some other local manufacturers'

A bit about RDB+:

http://rhapsodio-cmw.com/?p=11

Design: TWFK balanced armature (Dual BA) + Dynamic driver (DD) IEM. Available as acrylic universal [silicon or foam tips], or acrylic custom IEMs.
This is their second version of the TWFK + DD hybrid [the Rhapsodio thread expands on that].
Didn't really ask what size the dynamic driver was, or what the X-over design was like (or even whether it was 2 or 3-way ), someone else can (same goes for what kind of acoustic filters they use if any)

The TWFK sits inside the nozzle, and above it the DD is enclosed in an acrylic dome (inside the main acrylic shell), with a port at the top (a bass vent on the shell).
The IEM body itself is fairly big compared to universals (about 1.5x bigger than say Westone 4R, where the latter is designed to rest at the bottom of the concha, but the shape is different, so the comparison is a bit unnecessary), but smaller than full sized customs or custom universals with a helix lock (the part that extends up/to the side and locks the IEM in place, sometimes at the expense of comfort)
If you want more info about your ear bits, have a look at http://upload.wikimedia.org/wikipedia/commons/c/ca/Gray904.png
Here's a pic next to T-PEOS H100, for size comparison:
There are some comparisons with the UM Merlin below as well.

Options/pricing/etc: not too sure - ask Rhapsodio about the faceplates, colors, cables, etc. Currently they're on a $500 special (facebook and site), I know it includes a cable, but not sure what sort of cable [plain westone, or silver?]

Here are some samples of colors, faceplates, etc that Rhapsodio do. You can see they offer recessed westone sockets (soon), Shure extruding (now), and westone flush, various colors of carbon faceplates, wood, etc, and some rich looking colors.


The RDB+ I was sent to review had red/blue body, and black carbon faceplates and looked nice. [the shades/pattern changes with angle]

Quick description of Sound [impression based on some prelim listening]:

crisp highs, orthodynamics like bass and detailed and pleasant but not too forward mids. Coherent overall and with a good sense of space. Very very fun and detailed, but probably rather far from what people would call neutral.

General use considerations:

While these might not be most appropriate in a review, being aware of some of these can save both you and the IEM vendors a bit of time and money
Fit/Isolation:
As with any universal or custom IEMs (impression quality/general comfort, pressure build-up, etc), fit or comfort might be an issue.

If you buy a pair you should really find out what are your return or refit options. [shipping and additional work charges, and if possible in general]. And have a couple of different tips to try and if possible cables. Rhapsodio do offer free refit within 30 days of receipt by customer for customs, but I'm not too sure about universals(they at one point said there were options on altering the default shell, but then said there was only one mold. if you're interested - ask them).

At the sydney meet most people who tried the universal version seemed to have no problems.
Pressure build-up wasn't a problem, probably because of the vent.
The nozzle size shape/length and outer shell size usually affect both how secure the fit is and how well the IEMs isolate.
For RDB's current universal fit, the nozzle is not long, and expands closer to the body, and the IEM itself is rather full because of the BA in nozzle/DD dome above design. (the body is actually taller than UM Merlin (RDB-right in the pic)).

The RDB+ looks to be designed to rest inside the concha (fit and rest in). Unfortunately for me, because of how tall the IEM is, it doesn't stay in the concha if not held in place by memory wire.

Here are some pictures of possible fit scenarios:
Here are a couple of ways it ended up in my ear (you can see there are different ways it can fit across, and many aren't very good for it staying in)
Good positioning, not really sustainable per se for me:


Bad positioning:


Compare this to the way a larger IEM with a helix lock fits

This one has the memory wire as well (UM's westone-ish cable with long memory wire)

Tips:

For the seal you should try a couple of different tips. I prefer comply foam ones with wax guards for practical reasons, or large soft silicon ones [they give me roughly the same isolation and comfort. Sound is roughly the same, unless the comply tips are too long and the end squashes and blocks the nozzle]. The tripple and double flanges I had didn't fit me well, neither did small or med silicon tips.

Fit & Isolation Without memory-wire on cables:
For me - the left ear is fine, the right one doesn't hold in properly if I move around (and in general, because of how tall the IEM is) and if worn with the supplied cable around the ear, plug facing the top.
The IEMs aren't that big, and I can wear them slightly differently - plug facing the bottom, and the IEM rotated so that the part near the vent is hooked behind the anti-helix. (without blocking the vent)

Isolation felt pretty average if it doesn't sit in the concha properly though, providing about 10dB isolation max at about 1-3khz.

Fit & Isolation With memory-wire on cables:
I have a set of standard the westone cable with memory wire. I tend to prefer rigid memory wires to assist the fit. It holds the IEM in place and without having it fit perfectly inside the concha (if it's not deep enough), preventing it from sliding out [meaning I don't have to tuck it behind the anti-helix (or in case of ones with a helix lock - a bit of helix, anti-helix and fit inside the concha]. With memory wire I do get a secure and comfortable fit.
Compared to the full-size acrylic universals I have with a helix lock and longer nozzles, the isolation is a bit less [e.g. if I walk next to the highway or click my fingers]. Probably 5-6dB difference, not generally noticeable with moderate levels of music. [and a lot better than in the case above]

Wind noise from the vent:

If you walk around outside, moderate winds cause the outer vent in the IEM to make unpleasant sounds, loud enough to interfere even with loud music. If you buy one, ask if Rhapsodio solved this. UM Merlin have a recessed vent with an acoustic filter in it that makes no noise. RDB+'s vent has a plastic ring with a protective mesh inside it and that ring has sharp edges, possibly causing the noise.
Rhapsodio said they're working on the problem, but if you buy one and use the IEM in windy places – enquire first.

Durability:

Compared to metal or alloy IEMs acrylic ones can crack or shatter with relatively less impact[high fall onto hard surfaces or bump with lots of force into an edge]. You can still knock a solder joint or crack something on a metal or plastic universal, but it's less likely.
I've used custom universals for about a year and never had problems, but I'm fairly cautious. [the UM ones I had/have, met a few knocks and falls and are fine].
As far as build quality goes, the RDB+ shell looks to be without any large bubbles and done well.

Sound:

keep in mind my sound preferences when reading this section
Highs: Extended, present, detailed. Not sibilant. Good hats and cymbals. Sometimes I got a slight sense of purposely enchanced highs (this is where you say you hear something you haven't before )
Mids:Both lower and upper mids are forward enough to be present and enjoyable and sound detailed, but not too euphoric or irritating. There's a bit of upper mids sparkle, but not too much.
Lows:Very extended and ample in amount. The texture is good too. There's a lot of snap and kick and depth, but no bloat. It has a throbbing/heartbeat quality to it where you can feel the bass as you usually do with speakers.
Mostly reminds me of the modded T50RP, and LCD2 or floor standing speakers I have and really like [microlab 7c]
Soundstage: I don't generally find much in IEMs [probably because I prefer very mids and high forward IEMs]. These have seem to have more than I usually expect.
Genre suitability: I liked it for all genres I usually listen to:
Classical (Mendelssohn, Mozart, Beethoven, Rachmaninov, Schumann, Grieg, Brahms - piano or violin + orchestra concertos (full or chamber versions)). The weight of piano and drums was great, there was enough sense of space and the violin and piano had enough sparkle. While you might think the bass forwardness precludes RDB+ from being enjoyable with classical that's not at all the case. Overzealous mixes with too much drums aside, there's usually plenty of detail across the spectrum for a very pleasing experience. Even with nice large drums in symphonies or piano concertos the low end felt very appropriate, compared to the Sydney Symphony performances I've been to (they do have a very enthusiastic drummer though )
Heavy and power metal (Avantasia, Sonata Arctica, Royal Hunt, Machinae Supremacy, Kamelot), various rock (Emilie Autumn,Edguy,Pretty Reckless, etc), a bit of hip-hop, dubstep and pop/dance (which I'm not naming ) – the guitars, the drums, the bass, the vocals, the beats, everything sounded great. Compared to some more mids forward IEMs, pretty much none of the songs I usually find grating sounded harsh, but anything had a very nice amount of detail in it.

Overall sound:

I think Rhapsodio tuned RDP+ in a very interesting and compelling way [somewhere between Merlin and H100, which we'll get to in a few minutes]. It manages to blend the TWFK double BA and Dynamic drivers into an end result that's great for a variety of genres - with very strong deep bass, forward enough mids with great detail and detailed but not over the top highs.
I'd probably still classify them as...errr...'bass strong', since some people may find it to be too much (you with the Ety ER4p, or maybe Westone 4R?), but I as I mentioned before, I like the Beyer T1 or LCD2 levels
Occasionally, I did get a sense of 'too much of everything' or maybe a slight U-shape curve (L ? ), but it was mostly recording/mixing related. However, keep in mind, if you're used to something like AKG K500, or something very very smooth sounding or with a very rolled off bass, it might take a while to adjust.

Compared to UM Merlin:

RDB+ has more bass impact, and maybe slightly more depth/amount[more of a throbbing/heartbeat quality to it. I've really missed that quality after passing the review unit on, it makes Merlin sound 'soft' in the bass ]. As well as relatively less prominent highs and upper mids. Overall I think that made RDB+ more enjoyable for Metal/Rock/Dance, but still comparatively good for classical.
Comparatively, Merlin has relatively more forward upper mids and highs sparkle and amount. It still has great bass [deep, ample, hard hitting for say dance], but it's tuned differently - without the extra kick RDB+ has. Those two factors I think make it more enjoyable and euphoric for classical. Sometimes they make metal specifically too harsh [Royal Hunt in particular], but perhaps that's as much mastering as it is Merlin.
It's difficult to make a relative sound preference assessment, as I think a lot of people think Merlin is tuned to have extended bass,emphasised mids and extended/ample trebble. To me, the RDB+ tuning is a bit less extreme/more refined in the mids and treble, but more extreme in the lows


Similarly, you can also get a TWFK + CI (CI upgrade to your current TWFK IEMs, for a total of about $400), and it has a rather fun sound too. [probably not as refined, not vented/prone to pressure build-up, and not quite there with the bass, but about 85%]

Compared to Fullsize HP:

I thought, compared to Beyer T1 and Sennheiser HD800 in various set-ups RDB+ held up fine [detailed, full sound, the feeling of space and general refinement of the tuning]. I also preferred RDB+ to my GMP-450 and 435.
If anything, I'd probably describe RDB+ as LCD2 [heard on the meet before the last] or Smeggy Modded T50RP. [probably with improved mids ]

Compared to other Hybrids I own (AF78 and H100):

It certainly seems like making hybrid IEMs is not easy to get right. I think RDB+ is tuned by far more coherently, and in a way that makes it sound more refined vs both AF78 and H100. It's... Pretty much everything: The feeling of space, the mids tuning and the balance of highs and upper mids and mids vs lows.
AF78 is tuned very strangely in the mids - thick and not very detailed. H100 has a large lower mids dip, and is tuned to a supposedly objective target of some sort (golden ears target), but after weeks of use I gave up on the 'balanced golden ears sound' theory [going back to the conclusion that to my taste H-100 sounds horrible]. It's always possible to get used to a sound signature [stockholm syndrome in HP ] , but switching to and from H-100 the difference in tuning is immediately noticable.
For H100 you can feel a similar approach to highs and bass [with more upper mids and treble emphasis], but RDB+ doesn't forget the lower mids.

About the cables included and amp:

Cables

Rhapsodio sent 2 cables and a P&D amp-k pro amp to try.
I was pleased with both of the cables. Supposedly, they're both $160 separately, but cheaper if bought with an IEM.
The braiding on the blue/red one was very interesting - it was flexible, yet didn't tangle and didn't conduct physical noise up the cable - combining the perceived advantages of flat and round cables . I'm not a big fan of the red/blue color scheme, but it also comes in a much more appealing [imo] dark brown/goldish color.
The silver cable looked very nice, and was extremely flexible too. [a lot of people at the meet liked that one]
Plug wise, the blue/red one had what looked like Oyaide mini, and the Silver one - viablue
As mentioned at the begining Rhapsodio can do all sorts of plus at either of the cable ends, and all sorts of wire and insulation materials. They can also do something similar to metal memory wires - memory wires using heatshrink (where you'd need to heat it up for it to take shape).

Amp:
http://rhapsodio-cmw.com/?p=1281

You can see a lot of transistors and the particular opamp used inside
The amp is interesting too. it makes the IEMs sound 'mellower' (a bit less bass impact, and highs crisp) [this is as opposed to O2 amp making it crisper] but still kept the detail and overall sound. At the meet I used it with HD800 and Beyer T1 with pleasing results and plenty of space on the volume dial even with quiet classical. However, it uses 2 9V batteries and does not include a charging port. The version I had also had the vol knob attached too firmly to the vol pot, making volume adjustment a pain past and around the middle.
Some pictures, including of the board are inside.

Overall?

If you're looking for a full sound with an orthodynamics like bass, without compromising on vocals or a sense of detail and aren't afraid of acrylic universals - I'd certainly recommend RDB+ . Talk to Rhapsodio - see what they can do in terms of how it looks/cables, etc.

Price-wise and competition from upcoming TWFK+DD - it depends - $500 is pretty good [compare to Cosmic ears on one end and UM, Aurosonics, Tralucent on another].
Will the upcoming Vsonic(1 cheaper and one similarly priced Hybrid, not sure about the driver configurations anymore?) and T-PEOS IEMs with a similar design and a speculative price of about $150 less, sound better to your preferences? I can't tell you that.