I use both Sonar (8.5) and Reaper. when I import a project from Sonar to Reaper, everything imports fine, including all the channel events in Event List. But when I record new midi in Reaper, or drag notes from one inst to another, or copy/cut/paste from one one to another, the channel number gets reset to 1. 
My question is, does this matter? Do I need to change all the numbers to the "correct" channel number. 
Let me give an example: I decide to move some notes from the flutes to the oboes. flutes are on ch 1, oboes on ch 2. After import, all the ch numbers are correct, all the flute events have ch 1, all the oboe events have ch 2. but then, I make changes, as above. The new notes on the oboes will have ch 1, instead of 2. This applies to any insts I may copy to. If I copy some viola notes (ch 14) to the cellos (ch 15), the notes in the cello will have ch 14, when they should have ch 15. I can change them to 15, so they match all the other cello notes, but of course it's an extra step.
I realize this is a question more for the Reaper forum, and I have a thread there, but after about 20 responses, the issue is still unresolved. I also have a thread on Sonudsonline, no replies there yet. I'm posting here because I know the knowledge level here is deep. Also, it's a question which applies to all DAW's, and therefore would be helpful to anyone encountering this problem.
 
To summarize, does it really matter what the channels are in Event List? If they get changed, does it matter? I'm not talking about the routing between your tracks, keyboard and synths, that of course matters a great deal. but these synth channels appear to be just virtual channels, so am I just obsessing needlessly?
 

Keep in mind that you choose midi channels to record on or from and choose midi channels to play.  They do NOT have to be the same.  I have to assume that you are recording on midi channel 1 so that is the way your instrument is set up.  However, the channel you play on will have to be re-set otherwise you will have everything on channel 1.

Thanks for the reply, Studio Guy (did it again, I keep rhyming lately). My keyboard has no controls, it's extremely primitive (I do plan to upgrade). So yes, I think that's why when I record the channel comes out as 1. Of course, when I set up, say, the Play synth for my East West instruments, I set a channel on Play, so it communicates with my DAW. But you're suggesting that when the channel flips to something else, it may matter? There doesn't seem to be any difference in the sound if the channel in Event List changes from 14 to 15. I mean, the pan doesn't change, or volume or velocity. Those channels just seem somewhat arbitrary to me.
 
I have tried to find some definitive guide to midi channels, and have spent some time reading, but I still am confused about the different channel types. There's the channel my keyboard plays on, which is always 1. Then there's the channel you set on synth for each inst, which corresponds to the channels you set in your DAW. These have to be the same. Then there's these channels that show up in Event List. for some reason, Reaper doesn't seem to care about these, it flips them (actually, it resets to 1 if I'm recording, and it keeps the channel of the "donor" inst if I copy notes to another inst). I don't know if this is a  flaw in Reaper, or they have figured out it doesn't matter. 

I would read the manual for your keyboard. All keyboards I've ever used can send on any channel. 
If not, I don't know anything about Reaper, but every DAW I've played with also has a channel select for incoming data. I always set Sonar to Omni but you can select any channel. 
 

The channel notes events are on will matter a great deal if you are using a multi-timbral instrument, software or hardware, which is playing different sounds (or 'instruments' if it's a General Midi module or plugin) and separates which note/event applies to which sound by MIDI channel.

For example, let's say you load a synth and tell it to play everything on channel 1 as 'piano' and channel 2 as 'violin'. Any MIDI it receives on channel 1 will control just the piano, everything on channel 2 the violin and it will ignire every other channel. So if attention isn't paid to what channel notes and controller events are on things might well not work as you expect.

What makes things both complicated and simple in Sonar is that Sonar can receive MIDI from a controller on, say, channel 1 and seamlessly redirect it to a synth using channel, say 2, another synth on 3, another on 4 and so on while keeping each synth's MIDI separate and tidy. Sonar is acting as a complex MIDI router. Additionally the MIDI channel a MIDI track is set to determines the channel it outputs on, not the one(s) it receives on.

Mixed up MIDI channels within the same track generally aren't a good idea and can come back to bite you in all kinds of ways later on. Especially if you have or get any hardware that uses MIDI.

I can't comment about Reaper's behaviour, I don't use it.

When playing back in Sonar the recorded individual channel notes do not matter at all. They are overidden by the channel output setting of the track they are placed on. 

Thsnks Cactus and TIW. 

Cactus Music
I would read the manual for your keyboard. All keyboards I've ever used can send on any channel. 
If not, I don't know anything about Reaper, but every DAW I've played with also has a channel select for incoming data. I always set Sonar to Omni but you can select any channel. 
 

My keyboard transmits on 1. I can set Reaper's routing to either Source or 1, it doesn't seem to make a difference. I also put in a send to the Vsti the inst is on, and the specific channel it's on, on the Vsti. Those don't change, otherwise no sound. I'm talking about the channel each individual event is assigned when recording midi, or moving clips around. I'm thinking those channels don't matter. But I keep "correcting" them anyway just in case. Honestly, I might as well, as I usually have to go in and adjust velocities anyway.
 
TIW: Yeah, that's my fear, that somewhere along the line something is going to get weird, like suddenly the pan changes, or volume or velocity. so far, that doesn't seem to be happening. but it seems logical that it could.

tenfoot
When playing back in Sonar the recorded individual channel notes do not matter at all. They are overidden by the channel output setting of the track they are placed on. 

Bruce, that's what I think. I think the channels in the event list are artifacts that get, as you say, overridden by the routing settings. You're the first person anywhere that sees it this way. I think the Reaper devs, who obviously know a whole more about this stuff than I do, didn't build in a "fix" because it doesn't matter. A solution in search of a problem. Hopefully, this is the case. Now, if I can just break myself of the compulsion to keep "fixing" them...Perhaps more St. Johnswort is needed...

tlw
The channel notes events are on will matter a great deal if you are using a multi-timbral instrument, software or hardware, which is playing different sounds (or 'instruments' if it's a General Midi module or plugin) and separates which note/event applies to which sound by MIDI channel.

Again - when working in Sonar - no they don't.  Multitimbral synths will recieve channel data assigned to the output channel of the track the data is on. They simply do not matter at all! The only exception is if you are saving and loading midi file type 0 files where all data is on a single track rather than type 1, in which case you are living in 1982 and probably not using Sonar:)
 
No harm in changing them all of course if you are young and carefree. For an old bloke like me it's pointless use of time I would never get back

michael diemer
I think the Reaper devs, who obviously know a whole more about this stuff than I do, didn't build in a "fix" because it doesn't matter. A solution in search of a problem. 

 
I think you are right Michael. It seems to be a legacy of the midi spec.