The note in the horn stops sounding when the F in the trombone begins. The F in the Trombone stops after one bar too. I have no idea what the problem is and I have not been able to find anyone with a similar problem. The only two solution that has worked for me is to set a higher tempo or switch instruments to strings. It seems like there is a maximum length of the brass notes. But it should be possible to play a brass note for two bars in 70bpm. It’s not even that hard, and even if it would have been impossible I wouldn’t want Dorico telling me that.
You didn’t say which instrument library you are using? Pretty sure any maximum is there instead of Dorico. Out of curiosity, I made one 10 times that long in Dorico trying both Halion, and Abbey Road. No issues - but I played tuba as a child, so I don’t usually write long notes 'less the register is higher.
It sounds as if your Horn and Trombone are using the same MIDI channel so that the MIDI-on’s and MIDI-off’s are interfering with each other.
If you set the Horn (temporarily) to a string sound in Play mode, does the problem disappear, or do both Horn and Trombone now both sound like strings?
If upping the tempo fixes the problem, the instruments don’t play on the same midi channel. It is then likely to be an issue with fixed sample lengths. You will have to switch to a better library, then. Probably not what you want to hear, though .
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