I just traded in my old Kurzweil stage piano for a Yamaha P35B keyboard, and I like it a lot. However, I'm having some trouble getting the MIDI to work properly. The keyboard transmits on channel 1 by default, and it works fine for playtback and recording most of the time within Sonar X3e, but if I open a second project, the keyboard does not play or record unless I turn the keyboard off and back on. I need to do this every time I switch between projects, and right now I have a project open where that doesn't even work. When I recorded the piano a few minutes ago it worked, then I switched to another project, requiring me to reboot the keyboard, which was successful, then when I went back to my first project again, I reboot the keyboard and it still doesn't work.
 
1) Why do I have to keep doing this every time I switch projects, and
2) Why does rebooting the keyboard not even work for this one dummy project?

Sorry that your post was ignored for so long, It's a bad time to use the forum right now with all the new release babble real questions are getting pushed to page 2 fast. 
 
I would go into preferences MIDI devices and make sure your MIDI Sport is working. I think there are a lot of reported issues with those. Download the latest drivers too. 
What is happening is Sonar is loosing the MIDI sport drivers. 
It's nothing to do with the Yamaha, MIDI is MIDI. 
You might want to start thinking about a new audio interface with midi built in. I've never had issues using a system like that. 

Thanks. The Midisport has been working fine for a few years, and this behavior started as soon as I swapped the Kurzweil out for the Yamaha. So it seems pretty unlikely the Midisport is at fault. 

jkoseattle
...if I open a second project, the keyboard does not play or record...

Can you clarify what this means? Is it that SONAR does not register or record MIDI input from the keyboard, and the keyboard's synth does not respond to MIDI Out from SONAR on playback? What does SONAR's MIDI Activity Monitor Show? (Preferences > Display > Show MIDI Activity Monitor on Windows Taskbar)
 
I gather the Yamaha's MIDI I/O is connected via the MidiSport rather than via it's own USB-MIDI interface; is that right? And are you input-monitoring the audio back from the Yamaha or does this MIDI input issue also affect playing soft synths? Depending on the answers, you might need to do a little more testing to determine whether this is a MIDI issue or an audio issue.
 
Are you echoing MIDI back to the Yamaha via SONAR, or using Local Control? If using Local Control, one possibility is that the Yamaha is responding to the Local Control OFF message that SONAR sends when opening a project, whereas the Kurzweil was not. My Roland keyboards do not respond to Local Control OFF; I have to set it manually every time I power up the keyboard. Input-echoing MIDI via SONAR is preferred if you're going to use the onboard-sounds of the keyboard synth, though the MIDI round-trip will add a bit to the overall latency.
 
EDIT: Swapped keyboard names everywhere because I see I got it all backwards the first time.

Yes, I am using the same MIDI I/O setup that I had for the Kurzweil. Basically I just unplugged the cables, bought the new keyboard, and plugged it in the same way. (Well, new cables actually, I gave the buyer my old ones.)
 
Thanks for the response. I think it has something to do with this. According to the manual, this keyboard has Local Control ON and cannot be changed. I want to use the keyboard for both controlling soft synths as well as its own piano sound. I've always been pretty confused by the Input Echo thing, to be honest. In addition to the MIDI cables going to the Midisport, I am also routing the audio output straight to my mixer so that it comes through the headphones rather than through the Yamaha's own speakers.
 
If Local Control will be always ON, am I going to get double hits because I'm also sending Midi back through Sonar? Can't I always simply turn the volume down on the keyboard?

Is the Yamaha keyboard generating active sensing messages that the Kurzweil didn't?

I have no idea. How would I find this out? Also, I'm coming to realize the value of Local Control being OFF. I cannot record a soft synth without also hearing the Yamaha piano unless I turn the volume down on the Yamaha. Then when I play back I have to turn it back up if there's a track using the Yamaha's piano sound. PITA. I looked online and the P-105b keyboard allows Local Control ON and OFF. Plus it uses USB MIDI rather than the Midisport. Maybe that's what I need.

If you can get your total round-trip audio latency under 10ms or so, and you have enough inputs on your interface, you would do best to connect the audio output of the keyboard to your interface, and uses Input Echo on an audio track to echo it out to your monitoring system. Then you can disable Input Echo on that track when working with other synths and you won't hear the audio even though local control is generating output. The only downside then is that your won't be able to hear previously recorded MIDI tracks driving the keyboard synth in real time; you'll have to record the audio as soon as that part is ready.
 
I'm still not sure how you would lose audio when switching projects given that the keyboard synth is under local control, and the output is apparently being monitored directly via a hardware mixer. Your PC wouldn't even have to be running in that scenario to hear the keyboard synth.
 
I think you'll need to clarify exactly what's in the projects, what synth you're expecting to hear in each case, what track has focus, and whether you're relying on Always Echo Current MIDI Track, or explicitly enabling Input Echo on soft synth MIDI or Simple Instrument tracks.

Did you follow my advice and look in midi preferences to make sure the midi sport midi input is on the list when it stops working? 
Are you choosing the "midi sport omni in" as the input device option for the new midi or instrument track? 
The input echo needs to be on ( purple) to hear sound from soft synths. 
You can shut off midi output when you don't want to hear the piano on playback. 
There's a chance that if you turn the piano's volume down while connected to a soft synth you could also turn the volume of the soft synth off via CC. 
There is also the midi tray icon that should show activity. 
The new midi cables??. ( long shot there) 
 
According to the spec sheet it does not have USB connectivity. 
 
http://usa.yamaha.com/products/musical-instruments/keyboards/digitalpianos/p_series/p-35/
 

I skimmed the thread - so if I missed something, please forgive me.
 
I did have a thought.
 
I am wondering if perhaps the reason the drivers are 'lost' is because of a default setting in Windows - called USB Selective Suspend.
 
By default, Windows has USB Selective Suspend 'Enabled', and that tells Windows it can periodically conserve power by suspending idle USB devices.
 
Most folks I am aware of go into Control Panel Power Management Options, and pick the High Performance power plan, further modifying settings to eliminate display monitors and hard drives from going to sleep/hibernation.  Additionally, under the following, set the USB Selective Suspend Setting to 'Disabled', then back out and Save Changes if asked.
 
Give the above a try - if it not already being done, and see if that helps eliminate the need to turn your keyboard off/on.
 
Bob Bone