Need help! Can't get my head around making a midi grid to match the 'feel' of a player. I use Logic Pro?
I have good news and bad news.
The good news is--you can relatively easily make a MIDI tempo map to match the feel of an audio track in Logic Pro 7.
What you want is the feature known as the "Beat Mapping" track. This is one of the Global Tracks. You can activate it in the local View menu of the Arrange window.
You'll want to read the manual (or if you own my book Logic Pro 7 Power, it's in Chapter 5
) for the full details on how to use the Beat Mapping track. But the basic concept is simple, and works like this:
1) Activate the Global Tracks and its Beat Mapping track in the View local menu of the Arrange. You will have an empty track above your Arrange tracks.
2) Select the audio file with the "feel" you want to create a MIDI tempo grid from.
3) Drag the file onto the Beat Mapping track. Logic will then analyze the file and detect its transients, creating one tempo event on the Beat Mapping track for each transient detected. The result will be a Beat Mapping track filled with thin white lines representing tempo change events based on the analysis of your audio file.
4) In the Beat Mapping track, you can then move, add, and delete tempo events graphically to more precisely match the newly created MIDI tempo change grid to the audio.
And that should reclock your MIDI tempo to your audio!
Ok, the bad news: how effective the Beat Mapping track is will depend on your audio track. The more pronounced and obvious its transient beats, the better the mapping will be, and the less "clean up" you'll have to do. If you use a relatively clean and sparce freeform drum track, for example, you'll get great results. But if you are feeding it a very washy and wet synth line...well...good luck.
Here are two quick tips to get you going:
1) Have it analyze a region that begins at the start of your song. You technically *can* use any region but I find if you start at the beginning, the results are better.
2) The Beat Mapping analysis function works on MIDI as well as audio. So if you're trying to map an audio file that is particularly difficult, you can often get precise results by creating a MIDI "guide track"--in other words, if you're trying to beat map a very complicated piano line that isn't working, record another MIDI track using for example a cowbell, and just tap all the quarter-note beats along with the piano part. Then have Logic beat map the MIDI guide track. That should work well.
Hope that gets you started!