Hi. I have recently worked through the excellent Logic 201 tutorial section on beat-mapping and I have a question regarding its application. I posted this on the Sonikmatter forum a couple of days ago but have so far had no response so I thought I'd post it here and see if anyone might have some insight. I hope that's cool. I am working on a piece which is based on a long, picked acoustic-guitar track. That track was recorded to the click and lasts about 4 minutes. The recording sticks fairly well to the click for the most part but not perfectly. I want to add some other tracks to it, drums and bass included. The drums are based on an initial midi loop which will be varied throughout. When I played the drum track over the guitar, it really showed up the imperfections in the guitar in terms of it wandering on and off the grid. So I tried quantizing the guitar track in the sample editor using the "Guitar picked" setting, which turned out pretty hopeless. Then I went back to the original (thankfully I'd backed it up!) and beat-mapped the whole thing. Now it's pretty good, much better than before. Obviously the drums now lock to the new grid and play in sync with the guitar. However, as the tempo goes through its multiple changes at some places this is really noticeable, mostly where the snare falls just a little too late or it audibly picks up the tempo just a trace etc. Now it's not too bad - I think I did a reasonable job of the beat-mapping in that there aren't too many very radical tempo changes - but the result is not really good enough. I'm wondering if there is a way to neaten this up in the places that need it (or all the way through). I've tried shifting the drum hits a little at those points as well as choosing different nearby transients but that throws the groove out in a different way. Also, is what I have described above the best way to proceed or would it in fact be better to quantize the audio track, obviously using different/better parameter settings than I did before? Any help appreciated.

My apologies if the lack of any replies to this was due to the fact that I had posted the question to another forum as well. I'd rarely do that; it was just that I was really stuck on this issue. I have recently purchased most of the Logic tutorials available on this site and find them absolutely brilliant; I am learning a huge amount from them. I am saying this just to register that I am a serious user of this site and also that I do hope to post other questions and so on if they arise (yes, here only). The lack of replies may of course be nothing to do with all this; it may be just that nobody has anything particular to say about the issue, which is fine. In that case, just consider me certifiably paranoid!

Couple of ideas. 1) sometimes tempo fluxuations can seem abrupt if there are not enough beat mapping markers. See if you can identify more sub beats to create a more gradual accelerando. 2) Assuming this is not a classical piece, there are probably sections of the song that repeat. Can you replace the part where the tempo begins to speed up with a similar section from earlier (or later) in the song. Sometimes creative editing does the trick. 3a) if you need to use the audio quantize, try quantizing only the sections you want versus the entire track. 3b) Sometimes the audio engine being used makes a huge difference. Acoustic guitar is one of those things where its very difficult to do without artifacts. I have alternate algorithms that I select, Speed from SoundToys can sound good. Also Izotope makes Radius. bd

Hi bd and thank you very much for your informative and helpful response. These are great suggestions. Some thoughts on them: 1. I have gone through it before, increasing the number of transients and linking them to sub-beats as you suggest here. It seemed to make the tempo a little wilder in my case with shorter but more noticeable shifts. I'll try again with your idea of 'gradual accelerations'. 2. I considered doing this but would that not throw out the whole existing beat mapping, which is fine in general? Or does cutting/pasting sections leave the existing mapping intact? I'd rather not have to go through it all again. 3a. Good idea. Again, I wonder how the newly quantized sections would fit in with the rest of the file in terms of audible artifacts and timing issues? Guess there's only one way to find out.. 3b. Yes. I'm not sure Logic is the best at this sort of thing. I have been considering trying out Melodyne. I'll look into these others you mention. All-in-all I have gone ahead and built on this track in terms of adding other instruments. It sounds okay and the tempo changes are not too noticeable as the piece fills out but with this new info I'll go back and see if I can tidy it up some more. Thanks again bd for your help. Mark