This is the first, and by far the simplest of the tutorials I will start writing. This is my first time writing a tutorial, so I will do my best to make things as clear as possible, I hope I will get better at it with time.
Making a loop is fairly easy. You can do it with just a drum track. If the track is 10 seconds long, and is totally dry (no reverb) - then you'll never notice the 'loop'.
This is what Spectrasonics Stylus RMX does to great effect.
However, what do you do if you have reverb on your loop? Reverb is supposed to die away naturally, but if at the loop point you go back to the beginning of your loop, you're screwed, because the reverb is not going to be at the beginning of the track. (Some game engines now have inbuilt reverb engines to cover this, but it's best not to rely on these as it makes the game engine work harder, which you don't want wherever possible).
Let's demonstrate with an example. Here is a bad loop.
If you were to play this track over and over again, (the last hit is at measure 41, and then you can see a long tail where the sound dies out) - it wouldn't really be a great loop, because all the momentum is lost at measure 41). Have a listen for yourself. The recording below is the loop from measure 33 to the end of the WAV file, and then the loop starts again at measure 1.
As you can see, the loop totally sucks. So...what do you do about that?
It's pretty simple.
First you need to cut the reverb tail off the end of the loop (in this case, the reverb tail starts at measure 41). Then make a new audio track for the reverb tail.
Then place the reverb tail that you just cut, at the beginning of the sequence.
Now, at measure 41, it will loop back on to measure 1 with the reverb tail playing. This will make a truly continuous loop.
Finally, just to avoid any clicks and pops which sometimes happen when cutting up audio files like this (my audio files are a bounce of the MIDI sequence through which I composed this track) - you should add miniscule fades to the beginning and end of each audio region, the fades should be between 3-5 milliseconds in length. This will avoid any pops and clicks and should make for a totally seamless loop.
OK, now that has been done. Let's do a 'before and after' comparison.
So, here is the loop, looping at measure 41 in the sequence back to measure 1, WITHOUT the reverb tail. (The loop occurs at 00:13 into the clip). It works, but it's not 100% satisfactory, and is most definitely not seamless.
Now, here is the loop, looping at measure 41 in the sequence back to measure 1, WITH the reverb tail. (The loop occurs at 00:13 into the clip). It works, and is seamless. The first version without the reverb tail works fine, but the second version with the reverb tail is a definite improvement, and is much more impressive to an audio director. The difference between the two is definitely audible.
I'm not suggesting that this is the only solution, because it isn't, but it's certainly a method worth considering to just improve and tighten up your game loops a little bit more. It works particularly well for ambient cues, aleatoric / atonal cues, and cues with relatively little harmonic movement. I'll cover that in depth later on in this series of tutorials.
Looping music is a key component of game audio, so it's worth getting these nuts and bolts right if you can. I appreciate that for many of you, this is pretty obvious already, but I hope that this series of tutorials will grow to be a resource for newcomers to audio development.
You can hear an extended version of this cue in the 'Videos' section of my ModDB profile.
Questions, comments and thoughts are most welcome.