Hi,
 
I have an old song with  just audio, no midi. It's at 100 bpm. The song is actually at about 87 bpm. I was never going to use midi, so I disregarded the bpm. I want to do some things now with midi and Melodyne, but when I modify the tempo, audio events move.
 
Can I tell Platinum to disregard the 100 and change to 87 without the events moving?
 
thanks
 
 
 
 

Audio should not move if each track is one full clip from beginning to end.
 
Of course you will need to realign the first measure if you did not start at measure 1.

 
 
That's 2 mistakes made: Did not start at beginning and each track is not one full clip. I guess I'm out of luck.
 
Thanks though

You could use Reaper's digital varispeed. I believe that should work. It's what I do when I want to alter a master files tempo. Even better you can tell Reaper not to alter the key.

Ben

I have taken pure audio recordings and matched a tempo to them very close. 
These were always songs that were originally played to a drum machine.  This is whats important.  
 
I don't think it matters if the tracks start anyplace at all. Didn't for me. 
 
What I would do is set the tempo as close as possible first. 
Then I would select all and drag the song so the original count in would be on the first beat of the second measure. 
Now I would fine tune the tempo until the 4 count in lands on the correct beats. 
Next step is (if your lucky) look further along the time line and to the end and see if it's drifting. 
Now fine tune a little more until the end lines up. 
I guess my drum machine is pretty good because most times I could fine tune the tempo and the song would not drift. 
You might end up with a weird tempo like 84.234  
 
If the song drifts around then you use the audio snap (??) feature to create a tempo map. I've never done that but there are a bunch of threads on how to do this in last couple of weeks. 

you can do this in CbB!!!!
 
highlight all your clips and right-click and clip lock "position" all clips. Make sure that each track time base int the inspector is set to "absolute" and not "musical".
 
now you can change tempo without any issues.  you can use "Set Measure/Beat at Now" to get the click to match your audio if you can find where the beats are in your audio.
 

You can also change the tempo then use cntrl + shift and drag the edge of the midi clip and Stretch the midi clip till it's the correct tempo.

Since you apparently recorded without a click (?), I'm assuming that 87bpm figure is only approximate, in which case you should do this to get a more precise sync of the timeline to the audio:
 
- Assuming no partial 'pick-up' measure, trim the earliest clip(s) to the first downbeat transient, and slide everything back to start at 1:01:000.
 
- If there is a pickup measure slide all tracks so the first downbeat transient is at 2:01:000, snap the Now time to 2:01, hit Shift+M (Set Measure/Beat At Now), enter Measure 2, Beat 1 and OK.
 
- Play the track with the metronome off, and count measures/beats in your head out past the start of the latest clip in the project, and stop playback on a downbeat with Spacebar.
 
- Shift+M, enter that Measure and Beat, and OK.
 
SONAR will adjust the initial tempo (or the one you set at 2:01) to make that measure/beat in the timeline fall on the absolute Now time where you stopped playback. The absolute playback timing and sync of tracks will not be affected.
 
- If you had to set 2:01, edit the tempo at 1:01 to match it.
 
- If you find the timing of the audio is drifting around that average tempo (likely), you can set the Now time to other measure/beat transients before or after the last Set point, and Set those additional points as needed to really to lock in the timeline everywhere.

Or ... you can just redo the song. 
 
I used to think "O Man, that's the perfect take, I've got to save that to infinity and beyond..." but I've come to realize that's just my own egotistical laziness.  You can do anything all over from scratch, and it is the rare situation that the redo is not better than the original.  Plus sitting in front of a computer screen moving clips about here and there ain't nearly as much excitement/fun as strapping on the Strat and re-'gitting it'.
 
The only exception might be that someone is dead; but in that case why mess with it at all?

A valid point, in general, but it sounds like this is more than just one track, maybe including instruments the OP doesn't play, and/or performers that not available, and who might not know the song anymore years (?) after it was recorded.