Here I'm going to reveal some of my "secrets" for creating (semi-)realistic drum machine/ sequencer-driven drum parts. This process is not for the timid or impatient as it requires probably as many, or far more, hours than prepping & recording a real drumset. However, for those of us without access to the latter, a good room, good enough chops, or understanding neighbors, the following hard-learned tricks can help prevent that "fake" drum machine sound from marring your songs(of course, little of this will be applicable to styles employing the "drum machine sound"). I use the sequencer in a Korg synth midi-clocked by an old Roland VS recorder to trigger drum samples often combined with real, hand-played cymbals/hats, & hand percussion.
1. Tempo Changes: Unlike a drum machine, it's impossible for a drummer to play at a perfectly steady tempo; many may seem rock-steady, but their tempo is actually almost constantly varying by tiny amounts such as 0.1 bpm. Slightly more noticeable tempo changes can occur leading into changes & fills when drummers get excited as they anticipate the upcoming change. Tempos may shift during dramatic or mellow parts & songs often slow down as they reach their conclusion. Being able to clock your sequencer or drum machine from a source that allows one to create a "tempo map" is the key to creating subtle & smoothly-varying tempos. Take your time creating the tempo map as it can't be changed later if you've recorded live, unsequenced tracks played to these tempos. The Roland VS allows up to fifty measures of tempo & time signature changes & I often use them all wishing for more.
2. The "Extra-Limbed" Drummer: Don't inadvertently program drumset parts which could only be played by an octopus; just two arms & two legs. This may seem obvious, but it's not hard to make this mistake once one starts adding fills & crashes. Visualize/sketch the layout of your virtual drumset: could a real drummer hit cymbals or drums sequentially that are too far away for his stick to travel to that instrument's physical location in the time available?
3. Habits of Drummers: Now I'm not talking about things like complaining about how much trouble it is to transport & set up their kit or tuning/paradiddling while others are speaking. LOL ;-) I'm referring to playing habits which are nearly universal. Strong arm/leg hits(right for a right-hander) will be noticeably louder, so figure out which hand your virtual drummer would use for each hit & set individual strike volumes accordingly. Most every crash cymbal hit is simultaneously accompanied by a loud bass drum hit. Any accented beat will affect all simultaneously struck cymbals/hats/drums making them all louder. 16th-note(& 8th note) hi-hat/snare/tom/double bass drum patterns are rarely, if ever, played perfectly |x x x x x x x x x x x x x x x x|, they usually have some degree of |xx xx xx xx xx xx xx xx| such that the second hit of each pair occurs a little early. The first bass drum hit of any quick double tap will always be louder. Playing the drum samples manually on a keyboard(quantizing off), being sure to use your strong hand where your "drummer" would, will often get you closer to the desired feel which can then be edited to perfection later.
4. Dynamics: Most drum samples are already compressed to some degree, so don't immediately start squeezing the snot out of anything except for carefully tone-shaping the toms to allow their ring to be more apparent. Anyone who has played with a live drummer knows the incredible dynamic range of a drum kit. Therefore, be sure to program this into your drum part. As mentioned in the previous section there is a big difference between strong & weak-limb strike volumes & I've found that one really has to exaggerate this when programming for it to be noticeable; this is especially true with the aforementioned 16th(& 8th)-note patterns. Rides & hats need a huge variation between the volumes of their accented & unaccented strikes to sound real.
5. The Sounds: When a drum is played louder, it gets brighter in tone, mainly due to the increased attack velocity. Make sure your drum sounds are programmed to react with a natural-sounding increase in brightness relative to volume & that your velocity curve/scaling is properly-adjusted if you'll be playing parts on a keyboard. If possible, use a softer variation of the sample for lower-velocity hits. I also like to roughly tune my drumkit samples to the song whenever possible as long as the sample doesn't start to sound weird or "chipmunk-ish" as a result. Another often over-looked phenomena is that the pitch of a drum changes a little depending on where, how hard, & how fast it's repeatedly struck. Therefore, if your sound source/module has a "randomize pitch" feature, be sure to use it at the lowest setting that will allow repeated strikes to "chorus" ever-so-slightly preventing stagnant cancellation(make sure this is 'off', though, while tuning samples to the song). Also enable multiple triggering on all drumkit elements so each hit rings into the next to prevent "machine-gunning" on fills. One element I've never been crazy/patient-enough to try & simulate is the fact that whenever one drum is struck, every other part of the kit vibrates sympathetically to some degree producing additional overtones; I've relied on reverb & simulated "close-miking" to avoid the total nightmare of additional programming that would be required to emulate this subtle effect!
Panning is a matter of taste, but should reflect the sketch you made in 2. above; keep in mind, though, that the lower the pitch of the instrument, the less directional its sound will be: meaning floor toms, for example, will sound more natural panned closer to center than your sketch may show. Mixing is also a matter of taste, just remember that smaller drums/cymbals are always quieter. Despite all of this "sound advice"(ha ha) you will inevitably encounter situations where none of your available drum samples sound right; this is when it's time to use the real thing. I often need to add real mic'd cymbals &/or hi-hats to achieve the desired sound or playing technique.
Once your "drumkit" is recorded it will sound like a bunch of individually recorded bits(which it is) & unnaturally dry. At this point, I start to craft a digital room sound for the kit to serve as "glue" to make it sound like one drumset(bass & snare on their own tracks, but toms & cymbals usually as stereo pairs recorded at maximum width & then narrowed to taste later). I adjust this room reverb keeping in mind that the loudest, sharpest kit elements will have the most room sound(bass, snare, toms). Once I think I've got the perfect sound I turn it waaay down, so low that it's only noticeable when switched on & off as it's not intended to be the kit's reverb, only a simulation of the virtual room in which it was "recorded"; the main verbs will be added later as needed.
6. Conclusion: While I seriously question how many people will ever read this esoteric blog, I enjoyed writing it. Though few will have the stamina to actually invest the gazillions of hours required to implement all of these ideas & techniques, perhaps some will pick up a little something from this post that will help them add some extra realism to their programmed drums. Admittedly, I work with relatively obsolete equipment as I never went "in the box" pc DAW. There are lots of supposedly great drum construction software/ libraries/ plug-ins, etc that likely incorporate many of the ideas I've been doing "the hard way" for years, but maybe some haven't yet & you can implement them yourself using this newer technology. Have fun & when someone says, "Man, who's your drummer? He kicks ass!", you can keep it a secret or tell them you did it all yourself!
p.s. Got any other ideas, suggestions, or comments on this subject? Post them below... Thanks! Len