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Please try a bit better description of the problem. "some of the keys" what does that mean...? One key, more than one, are they working some of the time, or are they not working at all?

You can do a better job of describing your issue. Take your time. The fact that it is Yamaha to Yamaha has nothing at all to do with this... Any MIDI device connected to another MIDI is all that is necessary. A bad cable, a broken keyboard, anything could be the cause...

The reface DX is eight note polyphonic, do you know about polyphony and how it works?

The reface DX is eight note polyphonic, do you know about polyphony and how it works?

@Bad Mister I know that 8-note polyphony allows for eight notes to be played at once. Any more than that and the previous notes played drop off.

I am talking about playing ONE note which seems to drop off- I mean it plays, but the volume of the note is so low that it is extremely noticeable. This would be the a# (or b-flat) key from C5. Could this just be a midi issue with the MM8? I don't seem to notice it when playing sounds from the MM8's bank of voices.

Again, not enough information to make a determination on the Internet.

I am talking about playing ONE note which seems to drop off- I mean it plays, but the volume of the note is so low that it is extremely noticeable. This would be the a# (or b-flat) key from C5. Could this just be a midi issue with the MM8? I don't seem to notice it when playing sounds from the MM8's bank of voices.

One which sound or sounds does this happen. All Voices or just some Voices and which keys?

"a# (or b-flat) key from C5" ??? How many keys is that? Are you saying "Bb4" the Bb below C5?

Be specific about the Voice name and the exact keys. If you can. Thanks.

No, the B-flat ABOVE C5... sorry for the misunderstanding- if need be, I'll make a screenshot of my keyboard and circle the key in question in Photoshop.
This happens on ALL voices coming through the MIDI function from the reface. I do not know what you mean by 'dome' voices. No, just the ONE key. NOT all the 'octave notes' on the 88-key scale.

Does this make a difference, or do I finally get some kind of conjecture about what may be happening?

Also, all the cables being used are brand-new and came in the box with the reface. I got them in a 'bundle' from Kraft Music, where I ordered it. So no problems with the cables.

Thanks for any information you may have.

No, the B-flat ABOVE C5... sorry for the misunderstanding- if need be, I'll make a screenshot of my keyboard and circle the key in question in Photoshop.

No need the Bb above C5 is description enough. No photo is necessary.

This happens on ALL voices coming through the MIDI function from the reface. I do not know what you mean by 'dome' voices. No, just the ONE key. NOT all the 'octave notes' on the 88-key scale.

"dome" should have been "some" (iOS trying to finish my sentences for me, grrr!)

Does this make a difference, or do I finally get some kind of conjecture about what may be happening?

Nope not yet. You don't get a diagnosis from your doctor until he or she has enough information to make a definitive determination.

New cables do not necessarily mean they work, but I doubt it is a cable issue as that is not how cables "break" when then do. You are talking about 1 note out of many that work normally. Not a cable issue.

How about when you play the note directly on the reface? That will tell us something. Try playing Bb5 directly, the play it through MIDI
I'm sure you've done this - but you have not written this specifically and is it what the doctor would do if they were in the room with the patient.
🙂

And rather than say "ALL Voices" - pick one in particular so we can analyze what is going on in the programming - SCALING is a parameter that can control the output level of keys across the keyboard. A Bass sound might be attenuated as you go up the scale.

What you describe is not how MIDI "breaks" either so this is highly unusual. So if A5, B5 and C6 are playing fine but Bb5 is not we need to determine if your MM8 has an issue.

Do you have a sequencer or can you connect the MM8 to Cubase?
If yes, record yourself playing a scale including all the notes in the octave above and below Bb5. Take a look at the recorded velocity values.

That will tell you whether your MM8 has an issue or not. Let us know.

I have determined that the problem seems to be in my MM8. Still got 3 years on the warranty, so if I need it fixed, I'll contact Yamaha customer service. Seems to be intermittent, though, and not as prevalent on some voices as others, but still present, nonetheless.