Midis sometimes don't play properly

Hi there,

Ever since I upgraded to Windows 7 from XP a month or so ago, I've noticed a small problem with midi playback. I say 'small' because it doesn't affect very much - I've only encountered it in 3 midis so far.
The problem is that some of the notes are starting to cut out, or not play at all. So,
when a long chord is being played, it's quite noticeable when one of the notes suddenly cuts out, while the others continue going - or sometimes it just doesn't play to begin with. It's not quite random, though - it happens to the same notes the same way each time I play it, and if I change a few things round it happens differently, though again consistently if I replay it.

I'm not sure what my sound card is - when I go to Device Manager (which is what Google usually tells me to do), under Sound I see one 'High Definition Audio Device' and four 'NVIDIA High Definition Audio's.

The problem is most noticeable when I'm using Sibelius 4 to create/edit midis (though it occurs in all media players if I export the midi). I notice that, on seeing one passage that has this problem, if I mute some of the other channels, the problem gets less, and eventually disappears if I only select a few channels to play. Perhaps my sound card can't cope with too many midi commands at once? It certainly only seems to happen when there are a lot of notes being played at the same time.

Is there some easy solution to this? Thanks!

What MIDI Synth are you using? The built in Microsoft GW Wavetable or some other MIDI Synth?
The problem would appear to be in the MIDI Synth you are using rather than the sound card, as the sound card only takes whatever the MIDI synth sends to it and converts that to audio.

If you are using, for example Band in a Box which generates songs via MIDI, the old Roland GS MIDI synth is incompatible with Win 7 and they are supplying a new, Win 7 compatible, MIDI synth with the latest version.

If you are using a MIDI synth other than the Microsoft, check with the MIDI synth vendor for any Win 7 updates, since it apparently worked OK before you upgraded to Win 7.

I believe I'm using the built in Microsoft synth.

Sibelius 4 is the old version, I see Sibelius 6 is now the current version. I would check with Sibelius to see if there are any Windows 7 updates available. It could just be a compatibility issue with Windows 7.

It appears to be the Sibelius program. Do they have any updates to make it Win 7 compatible? Vista and Windows 7 handle some audio functions differently than XP so that could go along with what you are seeing in the XP mode.