Can you check the sound on a different instrument to see if both instruments produce low sounds? If so then the cause is likely NOT specific to your instrument. Maybe visit a dealer/friend and check their instrument?

all the sounds on the lower end of the keyboard sound excessively low

Not sure what 'excessively low' means but we assume you mean the frequency is too low rather than the sound level.

Checking C0 on a M8X shows 30 hz rather than 32.7 hz for a sine wave for both AN-X and FM-X. That is about 8% low. This was checked using VisualAnalyzer and examining the spectrum.

Is it possible that there is a fault on the keyboard, or is my age causing me to be doing something wrong?

Both of those are possible. The first step would be to determine exactly what frequency is being produced by doing a test similar to that mentioned earlier.

What engine are you using? AN-X, FM-X, AWM2? Are you testing with a simple sine wave and an Init Normal performance to eliminate programming issues?

Has it always sounded low or was there a recent change?

Can't speak definitively but the internal oscillators used to control frequency are likely dependent on one, or more, key voltage values.

If those voltage values are wrong it could cause the wrong frequencies to be reproduced.

One possible cause of wrong voltages would be using a 120 VAC instrument in a 100/110 VAC power area. Other related causes would be failing/failed capacitors or resistors.

The only tests you can do as a user are to measure what frequency is actually being produced. You would need to have a service center determine WHY that frequency is being produced if it is wrong.

Press the [UTILITY] button.  Then go to the menus "Settings" -> "Sound" (those are the first two columns on the left hand side).

Maybe take a picture and attach.  Octave Shift, Note Shift, Transpose, and Tune would be interesting.   

The above is from the owner's manual and shows default values.

Transpose and Octave shift both reset to 0 every time you power cycle the keyboard - so I wouldn't expect there to be any kind of issue.  I assume you've been power cycling and see the issue persists.

Tune would only impact the note by, at most, a semitone.  So that's not going to make a big impact.

Question: are you using the keyboard keys on the keyboard or are you using an external MIDI controller or computer or something external to "play" the notes?   Just curious because sometimes folks can mismatch octaves between external devices and Yamaha gear since the MIDI note for middle C isn't agreed upon between vendors (and frequently Yamaha is considered an outlier).

Also I assume you're using factory presets and not your own creations.  Because certainly you could misprogram a User Performance.  Something like a piano (CFX Stage, etc) that's a preset would be a reasonable Performance to stick with in testing if it seems unreasonably out of tune.

And I'm also assuming that if you play a chromatic scale from the bottom note to the top note (using a preset piano) that there is no pair of adjacent keys (notes that should be a semitone apart) that "jump" by an octave or more.  In other words, that it's not just the low notes that sound too low but the highest note is also off by an octave or more (also too low).

There are certainly other screens we can look at if your own creations (User Performances) are having issue.  Sticking with the global settings would cover most of the possibilities if you're not using an external MIDI device/controller to "play" the notes.

Yamaha designates note 60 (middle C) as C3. But Roland, Kort, Casio and others use Scientific Pitch Notation which is C4.

So if you send a C3 from one of those others that C3 will be note 48 and on Yamaha will be C2 which is an octave lower.

When mixing instruments from different manufacturers be sure to use 'Note Number' to specify the notes. Note Number is what in actually included in the MIDI messages and will be correct on any instrument.

To all those that have tried to help, I thank you, at the moment,  have some issues, so cannot devout any time to this, will sort it out when life is easier, once again, thank you.

No problem - hope you get things taken care of.

Hello everyone,
this is my first time writing on this forum, but I’m feeling a bit “desperate” and discouraged.

Fortunately, my MODX M8 does not have the issues I’ve been reading about here, but it does have others related to the keybed action.

First of all, I should mention that I’m a pianist: Yamaha C3 Series F, Montage 8 WH, and MODX 7+, along with other synths and master keyboards. In the past, I also owned the “old” MODX 8, which I sold to purchase the new MODX M8.

I’ll try to briefly explain the issue: with the black keys, it is not possible to play repeated notes at a slow speed. I’m not talking about Liszt-style repetitions, but simple repeated notes. This does not happen with the white keys.

To be clear: in “Take On Me” by A-ha, that G# repeated twice in the opening solo cannot be played properly. The first G# sounds fine, but the second feels almost muted, with a noticeably lower velocity. This clearly does not happen on the Montage.

I contacted the dealer, who in turn contacted Yamaha, and they promptly replaced the unit. Before the replacement, I brought it to an official Yamaha service center in my area, as required by procedure.

After a couple of weeks, I received a second MODX M8, brand new, sealed, and with a proper invoice.

Well: this one has exactly the same issue. I contacted Yamaha support again, but this time the technician dismissed me, saying that the problem does not exist and that even the previous unit was perfectly functional. Bottom line: it seems that all new MODX M8 units are like this.

Among other things, this technician told me that I’m the first person to complain about this issue. The dealer also said that no one else has reported it so far.

Is it possible that I happened to receive two MODX M8 units with this exact same problem? I don’t even want to consider that—it seems impossible.

I’d like to clarify that I didn’t expect the MODX M8 to have the same keybed quality as the Montage or a Fatar, but at least I expected it to be on par with the old MODX 8, which did not suffer from these issues.

Another aspect: the keybed is not uniform. When playing chords involving black keys, the white keys stand out much more than the black ones. It seems clear that black keys are at a disadvantage on this MODX M8. This, however, did not happen on the MODX 8.

Perhaps the new keybed installed in this series has not been tested sufficiently, or there might be some software or OS-related issue, or something tied to heavier presets (e.g., CFX Concert).

In any case, it is very difficult for a pianist to play on a keyboard like this.

I’m waiting for a future update—let’s see if anything changes. In the meantime, I’ll continue playing my Montage 8, which, I repeat, is a completely different story compared to the MODX 8 and MODX M8. There is no comparison, even though mine is the first model.

I sent an email to Yamaha to report this issue, but after a week I still haven’t received a reply.

I’m not asking for another replacement (it would be the second in just a few months), since this is already the second unit they sent me. At this point, I’m resigning myself to it.

I’ve been buying Yamaha instruments for over 40 years, but after this small–big disappointment, I will be more cautious.

It’s fine to produce synths that have something less compared to their higher-end counterparts, but the keybed should be 100% functional, because that’s where we place our fingers. It’s not acceptable to hear that, in a five-note chord, two notes sound softer than the others, or that you can’t even play a simple repeated note at a slow speed. Something is not right.

Pino

I can't really help you from a position of experience using (or having) the MODX M.  I can't recall playing on one yet and all I've done is some cursory playing (in the music store) of a Montage M or two.   None of which gives me any insight into the MODX M.

That said, and perhaps you've already tried this, you could use the keyboard's velocity adjustments to try to "slot in" the black keys better.   I think given your description there will always be some kind of compromise but what I'm thinking is trying the best shade of lipstick to apply to the pig.

1) Press the [UTILITY] button

2) Choose the left-hand menu tab "Settings" and next row choose "Sound"

3) Touch the "Velocity Curve" option which is to the left of the picture of the current curve setting

4) Try each to see if the response improves: Normal (default), Soft 1, Soft 2, Hard 1, Hard 2, Wide - ignore fixed unless you don't care about velocity.

Also I suppose if there's any truth to the claim that you're the only one with any problem (which I highly doubt) you can start to think about what may different outside of the keyboard itself.  Like finger position.  Maybe striking the very back of the black key or very front or middle or ... (somewhere) presents more of a problem to the new design and maybe you're "lucky" enough to have that as your natural location to strike black keys.   Of course it shouldn't be this way.  Keyboardists need to be able to utilize the full length of any key in order to accommodate for the various hand positions different sized hands require to play notes on the keyboard.   This idea I'm philosophically opposed to - but just offer any idea to try to better identify if there's anything that can make everyone identify what the shortcoming may be on the keyboard hardware side.

Hopefully others can pile on with similar observations so Yamaha can put more resources into looking into whatever they would need to do to address this.