Some notes don't sound

If they are red, they are outside the range of the instrument. And likely no sound , for the same reason

Looking at the mscx file I don't see a reason the notes don't play. They are identified simply as ties and there are no alterations in duration introduced by midi, the PRE or hidden ornaments. They are simply tied, and most (but not all) of the tied notes don't play. Why is a stop play command being sent to the synthesizer?

It's not supposed to work like this.

For some reason, the tempo/text markings cause this.
Remove these texts and rewrite them solve the problem: See: 1Si me falta el amor_.mscz
(I cannot reproduce from scratch right now)

@jlhueso: do you recall something about might be related (some operations with these texts in Tempo text style) ?

That's is it. As asked previously, can you tell us more on this point?

This issue also bothers me. In https://musescore.com/howard_c_/scores/5514131 look for measures 159 and 162 -- the notes of brass instruments starting on the first beat barely sounds. And for measure 158, those notes starting on the first beat (the low-pitch instruments) make no sound too (curious why this doesn't happen in measure 161). I used a rare time signature (3/2) and a fast tempo (200bpm) there, maybe this is the cause.

@cadiz1 Said something above.

I hear ever note, but I do hear the huge decrescendo in the brass for no reason.

Sounds like only trombones make some sound. Horns and trumpets have no sound at all.

I see what's happening now. You put a marcato on the note, which has the implication separation between notes and that's what you're getting. If you just want an accent insert a sforzato like you have on the trombones.

I understand, but when I start playing only very few measures before the affected measure, or just start playing from the affected measure, the sound becomes normal. Try downloading the score and play it in that way and you'll see what I mean.
Also I don't really know if this marcato implys separation, because the original score from which I transcribed this has marcato on it and I'm just copying it.

I downloaded it and the marcato notes are always shorter than the other notes. Until users are given control of the length of articulations, we will have to live with this, or change the definition in the .mscx file.

Oh I believe it's a misunderstanding, my bad for not making it clear. I have a hidden measure which is excluded from bar count ahead of this passage, so what I mean for measures 159 and 162 is actually 160 and 163 if you look at the bar count on the lower right corner of the software. The notes produced by brass instruments there all have accents (not marcatos), but they barely make any sound if you start too early. Only when you start right from the problematic notes or one or two notes before them can you hear full sounds of them.

I could tell which notes your talking about by the accents on them. I've been mostly starting playback at measure 154 according to the bottom right corner. This is so I have some context and can compare what I've been hearing to what you are describing. One thing to keep in mind is that notes with ties are silent unless you start them at the beginning of the first note. That's the main reason I've been starting at 154.

All of the accented notes sound accented to me in measures 160 and 163.

I have a version of The Great Gate of Kiev I did for version 2 here. I listened to it and he same things happen in it that I'm hearing in your version, except yours sounds better because of the new soundfont I'm using. Perhaps, that's part of the difference. I'm testing your playback on 3.1-beta and using the sound font that allows for single note dynamics, which is not possible in 3.0.5 and earlier.

For me the first beat of 160 and 163 produces very little sound if I start from 154.

Also I didn't notice 3.1 beta is already underway and single-note dynamics?! That's amazing, I can't wait to try it.

Wow you've done the whole series of Pictures at an Exhibition! I should really take a look before.

In https://musescore.com/howard_c_/mussorgsky_the_great_gate_of_kiev_organ… numerous playback failures occurred: (instrument analysis can be inaccurate because it's done by ear)

The first beat of measure 58, all instruments but strings went out;
The first beat of measure 62, only the tuba (including trombone 3), the organ (and probably the strings?) make sounds;
The first beat of measure 103, only the organ and the strings make sounds;
Measures 97-104, trumpets (and trombones?) went out;
Measures 157-162, all instruments but strings went out here and there.

And please be noted that if you want to hear those errors by playing it in MuseScore instead of on the website, you should start playing at least 3 measures ahead of the error zone. If you start playing from anywhere later, the results can be different -- some of/all of the silent instruments have their sounds back.

Getting kind of major now, really bothering me with some parts playing and other parts don't in orchestral scores.

I can't access the score you linked. Can you attach a score and give precise step by step instructions to reproduce a problem? Be sure to say which version of MuseScore and which soundfont(s).

Oh, my bad, I deleted the score from musescore.com, I'll attach it here. The problems are still the same, using MuseScore 3.1 and Papelmedia GM 2007 soundfont. Curious, the playback is completely normal using the default soundfont :O