I'm not a huge fan of programmed tracks, but they're here to stay. Programmed tracks are almost a necessity when you have a tiny home studio and not enough guns to bring in a full band (as I do). And popular music uses it extensively enough now to where it's no longer just a fad. But while some of us love the machine precision of programmed tracks and loops, some of us would like our machines to sound a little more human. Hardly anyone ever hears my recordings, but those that do always comment that if I hadn't told them, nobody would know I was programming. Here's a few little tips that I use for making my tracks sound more human:
The first thing is having a background in playing an instrument or five and having an idea how instruments you can't play work. Know the tuning range. Listen to the instruments one by one and get an idea how they're voiced in an arrangement. Listen for unique things that add character to the instrument (the tongue attack of a trumpet, the order the strings are played in a guitar strum, etc), and try to incorporate them if possible. You have to think like the musician playing the instrument you're programming.
The second thing is that you have to realize that there are some things a real musician can do that you just can't duplicate with programming. So if you've programmed something that sounds computery, you may have to simplify or modify your original idea in a way you'd rather not do. This happens to me a lot on Drum Fills
that end up sounding machine-like. I'll take out hits and simplify fills, sometimes radically, in order to make them sound more human. For me, it's more important to retain the human sound rather than crowbar in a fill that obviously sounds computery just because I like it. So be honest with yourself and simplify if you have to.
As an aside, I discovered through using an Alesis SR-16 drum machine that if you have a complex fill, for example a 2-beat snare drum roll, you can make it sound a lot less computery if you use two identical snare samples for the roll. The SR-16 has two samples per drum for that reason, and it works. I always use two samples per drum when doing rolls or quick fills. It's kind of a pain in the neck to do it sometimes, but well worth the extra effort in the end.
Third, quantize judiciously. I save the majority of my quantizing for the drums to get them tight, but I might not quantize a bass or keyboard part just to get it to lay in a more natural groove. This is tricky, though, because you still want it to sound tight, and if you're like me and not a strong keyboard player trying to play parts on keyboards, quantizing can be your friend. But rather than quantize every single note, just go for the ones that obviously sound loose and don't make every single note lock in on the 1 if it sounds tight otherwise. I'll often just recut parts if they sound loose rather than quantize them, especially if I'm trying to play laid-back against the beat. Don't be afraid to quantize, but don't be afraid to do the extra work of cutting a part that doesn't need quantized, either.
Finally, don't loop just because you can. Looping is fine for repetitive parts, but don't just create a 1-bar drum pattern and repeat it for the whole song. Create a few patterns with different fills and throw them in where appropriate. Actually play your instrumental parts from top to bottom instead of looping them. Musicians don't play every single note identically every single time they play them, and your programmed parts should reflect that. It's a lot easier and quicker to loop, but it's a lot more rewarding to play what you can in real time and only loop when it's more practical to loop than play in real time.