I've used the bar settings to do slow downs at the end of a couple of songs.

For it to sound natural, you should do the slow down, Rit, at the end of a song across 2 measures. However, to make it smooth and not sound like steps.... I make a few other changes. I make sure I have enough measures. Then I change the last four measures to 2 beats rather than 4. What I'm doing is spreading the tempo change across more measures, but with only 2 beats per measure it's effectively still only 2 measures (of 4 beats) in the context of the entire song. I then decrease the tempo by 10* +/- bpm in each consecutive measure with a hold on the last 5th one. this gives me 4 unique, closely spaced and reasonable tempo changes in the space allotted without any noticeable and obvious abrupt tempo changes.

So for example... the normal tempo is 120.... first 2 beat measure is 108*, next is 98*, next is 85*, next is 75*, and last is a hold. What you want is a smooth natural tempo change.

my song Dust on the Floor is a great example of what I just described. Feel free to listen to the entire song but the section I'm referring to is right at the end. https://soundclick.com/share.cfm?id=13017714

* the actual amount of the decrease will be dependent on the tempo of the song and what actually sounds the best and most natural Rit at the end of the song. You might need to experiment to get it right. I know I had to change the tempo a few times to get it right.

Edit: I am pretty sure you can use percentages but that gets complicated so just use the number you want.

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