Do you guys know WHY you're having trouble matching a perfect loop to a sequence you've created with the same BPM?? Theoretically, it should work, and sometimes it does right away, but more often than not, it's not synced exactly even though it should. Why?
We've all been in front of an audio editor with a loop on our screens. We sit there and make the loop perfect by nudging around the Loop Start marker, and the Loop End marker, until it's looping perfectly to our ears. You guys with me?
o.k.
but isn't it true that if you were to nudge the Loop Start forward a certain amount of time, and then nudge the Loop End marker forward the SAME amount of time - it would also loop perfectly even though our Start and End points are different? In fact, as long as we keep the same amount of time between the Start and End markers, we can move around that 'set' of markers in relation to the audio, and it will seem to loop perfectly. The listener is not aware that the loop may be cut at some weird point as long as it loops properly.
Problem is...
Cubase is very aware that you've cut at a weird spot.
See you've set your sequencing program to be the same BPM as your loop. In theory, if you have 8th note hi-hats in Cubase, when you import your loop in, you want the hi-hats to match all along the loop. (In fact, you want to add all kinds of instrumentation) ..but when you cut the loop in the wrong spot, what you get is...the first hi-hats are in time but get more out of time as it continues. But this isn't happening because your loop and sequence are at different BPM's, they're not - it's because your Loop Start is at an un-even time in relation to the 2nd & 3rd Hi-Hat.
For simplicity sake, lets say we know the 2nd hi-hat (or 8th note) is at sample# 200, and the 3rd hi-hat is at sample#300. In order to chop this sample to where it will loop AND sequence correctly when you add it to other compositions, you MUST chop the Start at sample #100.
Sounds complicated huh? "So Jizz...how the f*ck do I do all that??"
It's simple, don't cut or chop your loop in an audio program. Leave a little room at the beginning and at the end of your loop, and chop it there. It won't loop yet, but you're going to load that into your sampler/sample-player to trim it down perfectly.
This here is why MPC guys have been kicking software guys asses around, because software people always fall for that 'zero-crossing' nonsense...
o.k....when you load the untrimmed loop into your Reason NN19, you are now able to play a key on the keyboard to trigger the sample. Cool? cool.
Now if you look on NN19 (or whatever sampler you're using) you'll notice a knob that lets you adjust the Sample Start point.
Now here the part that takes a good musical ear...keep triggering the sample while adjusting the Sample Start at the same time. Just keep tapping, and twisting the sample start knob until you start to hear the kick drum at the beginning of your loop. That's where you stop, right? Wrong. Keep nudging the Sample Start until your trigger of the sample is actually in time. You should be able to feel whether your intitial 'hit' or 'trigger' is on tempo with the rest of the hi-hats. If it feels like you trigger the kick and theres a speeding up when the sample plays...adjust the Sample Start forward a bit (very fine adjustments). If it feel like your trigger is "rushing" the beat, it means you've gone too far into the sample, and you need to adjust the Sample Start back towards the beginning.
If you've done this right, you will be able to trigger your loop from your keyboard, and do lil' DJ-type effects by triggering the loop multiple times, then letting it play. Feel me?
This is difficult to explain on the net. But I hope I've got you guys to see there is like...a scientific, logical reason why some loops are chopped don't sequence well, and it's easily fixable.
Time-stretching is NOT the answer. And old-school drummers were NOT out of time, that's most laughable. These are rock solid grooves we're sampling, but cutting them in the wrong spot will make them appear out of time to our sequencers.
The above information took me years to figure out and understand. Mostly because I'm computer-based. MPC guys and hardware sampler guys already do this as they sample anything. They would never think of letting the computer tell them where the best "start" point is..lol. Anyway, enjoy.