Yamaha bass made in Indonesia (yeah ...!)
-Bolt (4 screws) in maple, rosewood fingerboard, 24 frets
Corps looks pretty flat (Alternative Internal Resonance: several "slices" of wood for an ulta-light weight and "SoundTube" crossing the bridge to the body that "recover" the resonance of the whole body)
Classical-mechanical oil bath of very good quality (very precise, smooth and progressive)
-2 Single coil pickups (microphones strips)
-2 Volumes microphones (with LED light) + 1 tone.
(I put 8 because the violin is good but the settings a little basic for my taste)
Passive-

UTILIZATION

This model RBX4 A2 (5-string model coming soon for the NAMM-08) jet black, meaning black with a gloss white edging (the back of the neck is also black varnish). It is fairly simple with a pretty line.
The neck is fairly thin and easy but setting a "tad" too dug for me (I like the strings very close to the handle). The truss rod is accessible side-body (as in the days of good watches fender, I personally + is the convenient access to the head but hey!) after removing a "small" cache (a little too bulky for my taste) and there! Surprises ... Truss-rod stuck Aiiiiiie .... It's more what it was Yamaha (for me, a serious brand needs to check and test the instruments a little better before we send them). In short after three hours of patience, oil and penetrating oil (yes, I had to try everything!) I managed to move a little but to force (it sucks!) and it turns sharply by quarter turn ... but I managed to set it straight (for cons I think I touch it every day (now, if the violin is good I should not really need in- I only changed very rarely pull).
Otherwise, the ergonomics are good with access to acute often very good as now.
Its key asset for me is its weight: it was the primary reason for my purchase: serious back problem after surgery and therefore impossible to play with my long and often watches good bass! Well that's IMPRESSIVE!
It is a real lightweight, it's great fun, we do not feel nearly on his back! It surprised even at the beginning, one wonders if it's a real bass or a toy after !?... 4 hours of play, it's just great! (10/10). This is the lightest bass I've ever tried (even a Curbow bass looks so heavy!).
Despite this I do not put that 6 / 10 due to blockage of truss-rod (not admissible in my opinion, I hope it's on mine!)

SOUNDS

In short, I was very curious and eager to plug it.
Good surprise ... It's a real low! (... Phew!)
It has a very good sustain and sound very clear and precise (which I greatly appreciate this model is super clean!). She has a pretty nice grain (not great either typed it must admit) and a good dynamique.Sa configuration is "classic": it's two microphones and a simple passive electronics and pickups 2 volume knobs are illuminated by LEDs (red and blue micro micro severe acute with a brightness depends on the volume, the tone knob is not lit ... Scrooge !)... not very useful gadget, or very "roots" but fun and rather nice I think.
For now, the most appropriate setting seems to be the maximum of two microphones (curiously gradually cutting the microphone becomes more acute on "hardness" with mediums colder ... ???... go figure!) with the tone a little more than half.
It sounds Péchu own (correct good for slap as well).
Do not expect a very versatile bass, I find that the settings are a bit "Spartan" (a single tone for the low / medium aigu...un knob would have I think, more versatility). Serious are good and accurate (very accurate in the lower cord of Mi .. attention, I think that everyone dislikes, some find it too "cold"). A good point: no knobs at all souflle acute background.

OVERALL OPINION

Well, I did not since 2 weeks.
"It is a good low" to plug and play "I say, ie not expect 150 possibilities of sounds but it sounds to my taste, pretty good and accurate (his second strong point, I think).
-The biggest plus is its weight, it's really REAL!
-Weaknesses include a lack of versatility and sound that some deem "cool" I think. (And for my case, a truss-rod DEFECTIVE !!!... the kind of thing turns me off a mark, it lost its prestige, right?).
It is a good value (if the "case" of the truss-rod is exceptional, of course) but for lack of vigilance, I do not buy the Yamaha I pense.Autre bullet (or very dark gray while ), I do not know if it comes from the shop where I ordered it by mail (I guess not, they look serious, but I received no booklet, no key, no jack! it is what it was, Boudiou! It's been a bit "cheap" for a 4 string to 550 euros, right? (I do not think Ibanez, for example, allows that!?. The price of instruments has declined a lot ... and with the quality or not ???... soon, they will deliver without strings perhaps).
In short, the best advice ... (sorry!) but to try to be sure it fits your needs! (A 5 string model (RBX5 A2) should be released, not right now it is not yet in 2008 catalog, I doubt a little bit of good rendering of a serious ... If a show?).

Edit: I appreciate more with time.
I was more accustomed to the sound of active initially but since, I found the real sound quality ... good little beast.
(The problem of Tross-rod was also finally settled walk ... nickel ... thank you !!!). oil + grease sleeve for excellent slap!