Hallo dear PianoClack members,
I discovered your forum as an alternative to pianoworld and thought I would share the problem I have with my new Yamaha NU1X, as some of you may be interested in this.
I copied and translated the description of the problem out of the Mail to my dealer:
While playing, I noticed that some tones that I play forte / fortissimo do not sound as expected, but quieter and more muffled, as if I had only played mezzo forte or even mezzopiano. This does not refer to specific individual keys, but can occur with all keys. At first I didn't think anything of it, but it became more and more annoying to me.
Today I tested it very systematically: I played several keys fortissimo one after the other. For example, the first two notes played sound as one would expect - but the ln the third key is much more muffled and quieter, so as I would have only played it mf. If I then play this key one or two more times, even with very high intensity, it only stays with mf instead of f / ff. If I now take a short break and start again, then the key that has just caused problems and did not want to be louder reacts normally as f / ff. If I then repeat the whole thing again with other keys, the next few keys sound again quite normally ff and suddenly dull / mf again.
I wanted to take a closer look at the MIDI outputs of the keys and connected the NU1X to my laptop with Pianoteq. The program allows me to see the MIDI output (between 0 and 127; the higher the louder) of the keys being played. And then I could observe the following: When I play a key f / ff the MIDI output is around 110-120. If, however, suddenly there is one key that is quieter, the MIDI output is much lower, at around 70, as if it were limited by the software. Since the sensors work with every key, and this problem can occur with every key, I assume a software-related problem.
Before the firmware update 2.10, the NU1X was affected with the so-called "loud note issue", where sometimes very loud notes suddenly appeared while playing. Examples of this can be found on youtube or forum.pianoworld. The cause of the problem was probably due to the fact that the NU1X only uses one key movement sensor, which does not work as precisely as three-sensor systems. The problem does not occur with the N1X / 2 / 3X or with the Kawai NV-5/10 with three (Kawai two) sensors incl. hammer sensor. After the problem was first denied by Yamaha, the "loud note issue" was "fixed" with the firmware update - apparently a kind of algorithm was added to the software to detect very loud MIDI velocities and reduce them to avoid the sudden occurrence of loud notes... I guess this mechanism contributes to the fact that the software in the Yamaha sometimes recognizes very high MIDI sensor velocities as "loud notes" and reduces them, which explains the sudden duller tones. Again: The problem does not relate to certain individual keys, which could then be assumed to be a fundamental fault in the sensor or the like, but affects all equally (or not).
Until I discovered this problem it was a fantastic instrument. But my impressions really make sense now in the retrospective, in some pieces where I had do play f/ff I sometimes had the feeling my strike didn't translate very well in a nice, loud, growling/piercing tone. I thought it was my playing and I have to adjust to the new instrument…
Today I visited the next big piano store in Berlin to test if this happens with their NU1X - it does! It seems to be a systematic error due to the "loud note issue" firmware-update "fix". The software/algorithm seems to detect intentional hard strikes sometimes (and way too often) as an unintentional "loud note" and lessen the MIDI-value, resulting in a too soft sound... But it's a false alarm. I can't believe it, how can Yamaha still produce and sell these pianos with this systematic error due to their non-sufficient one sensor system? And I can't believe how nobody has noticed this until now? It's less noticeable than a sudden out of place loud note of course, so for Yamaha this may seem to be a better "solution" than the loud note issue.
I will send it back - that the keyboard responds accurately to my input is the minimum requirement for any piano, and even my Roland FP-30 can do this.
Seems that there is no alternative to a NV-5S/10S or N1X, but they are much more expensive…