If realistic-sounding drum patterns are your goal, why restrict yourself to tapping little switches with your fingers when you could be whacking electronic drum pads with sticks?

BY NOW, HAVING faithfully read every instalment in this series, you are aware of the psychoacoustic subtleties of percussion instrument sounds, and why drum machines are limited in their ability to keep up with natural acoustic percussion in all its crude mechanical glory.

You also know that some of the inherent sonic shortcomings of drum machines can be overcome by using samplers in their place as your percussion sound source, especially if the sampler is carefully chosen and properly set up (and you've picked up a good many hints in those areas as well).

You've even endured a whirlwind tour of a number of currently available MIDI percussion interfaces which can be used to drive that carefully chosen, properly set up sampler.

Read on, now, as I forge another link in the Great Chain of Electronic Percussion Being with a discussion of the gadgetry used to trigger MIDI percussion interfaces.

They Hit Pads, Don't They?

AND THERE AIN'T much to 'em, really. At their most basic, they're just these things you hit that produce a trigger pulse which, in turn, triggers a sound.

So what's the big deal about them? Well, they provide a means to get around the inherent mechanical - rather than sonic - limitations of drum machines and keyboards. This point was left untouched (or perhaps taken for granted) in the last instalment, where the discussion of percussion interfaces assumed that you would of course be interested in adopting a set of pads as your percussion-programming device. An underlying assumption (of this entire series of articles, actually) is that you are interested in learning the techniques available for elevating electronic percussion programming to a level of rhythmic flexibility approaching that which real drums have always been able to achieve easily - and that you're interested in using these techniques to create percussion tracks which sound just like the real thing (at least on tape). Essential ingredients here are cohesiveness and spontaneity - the focused energy of a unified rhythmic motive, enhanced by the improvisations and minute variations that are the hallmarks of a live percussion track.

Well, I'm here to tell you - pushing buttons on a little box is just not gonna cut it. Some of you may have read about pads and interfaces and thought: "That's fine, but it doesn't help me much. I don't know the first thing about playing drums, and anyway, I can program any rhythm I can think of into my sequencer if I work in step-time..."

'Course you can - I won't argue. But those two little words - "think of" - may just end up weaving your best-laid plans into a tangled web before you get very far. Life's pretty short, isn't it? Why put yourself through that kind of torture - hour upon hour of tedious, brain-taxing accountant work - just to create a five-minute track that sounds, well, programmed? When instead, you could be playing music?

Using a sequencer, nearly anyone can create complicated keyboard pieces even though they may have no keyboard skills. But just the smallest amount of keyboard-playing skill will make it easier to record those sequences. The same applies to drum sequencing, now that the hardware is available to allow drumming skills to be used directly.

Before going on about pads, let's look at some other options. If you've been using one of the new crop of beatboxes with velocity-sensitive drum switches, hats off to ya. This is probably the greatest single improvement on the basic drum-box format that was possible, and at the least additional cost, although the full-tilt samplers which have such switches remain at the top of the sampler price range.

A variation on this approach, the velocity-sensitive keyboard (standard equipment on most keyboard samplers), allows similar dynamic input with the added advantage, since there are more keys than sounds, of being able to offer multiple tunings of a given sound, as well as more sounds, simultaneously accessible to the player. For that matter, it's not often you'll see someone playing a set of sixty-one pads.

This is a huge step up from having to use a pitch knob, or worse, having to enter new pitches on a keypad - both of which can kill spontaneity and make everything take five times as long. Incidentally, many drum machines which do not have velocity-sensing switches are able to respond to (and record) the velocity output of an external MIDI keyboard, and some with programmable pitches can do some fancy tuning tricks in conjunction with an external MIDI keyboard.

Nevertheless, these devices leave a bit to be desired when it comes to percussion playing because, quite simply, they are the wrong tool for the job. This business of playing drums with your fingertips on little keys and switches is enough to make a drummer curl up in a fetal position. Drumming is about Bashing Big Things With Sticks, for goodness' sake.

The non-drummers among you may not be familiar with the magical rebound dance of drumsticks ricocheting off of elastic surfaces. But if you have this process under control (and it's not as hard as you might imagine), you'll discover it lets you do things you couldn't dream of doing on a keyboard, and that the very feeling of swinging sticks against something can work wonders for opening up your sense of rhythm.

If you are a drummer, you'll know all about this, just as you know how frustrating, even futile, it is to try to translate your two-handed, two-footed rhythm grooves into the two-finger format.

"The differences in performance between brands of pads are subtle, and could easily take a back seat to such considerations as price, size or the style of mounting or interconnection system."

The bottom line is simply this. Percussion playing is a very intuitive, visceral process, and anything which constricts the physical aspects of it, or forces you into a lot of analytical thought to get the job done, is bound to detract from the result. You want to just play - and that is exactly what pads and interfaces allow you to do.

What's In A Pad?

MOST PADS CONSIST of a hard, flat surface with a piezoelectric transducer - essentially a contact microphone - attached to its underside. The top side is generally covered with a sheet of rubbery material to maximise rebound and decrease the noise and hand trauma of stick impact, as well as, in some cases, acting as suspension and shock isolation for the hard surface (or batter, as it would be called on a drum).

On top of this, there's usually some kind of interconnection and stand-mounting hardware. All of the above is then sealed into a rugged plastic housing in a style that should, with luck, be distinctive enough to avoid a trademark-infringement lawsuit.

All that aside, the differences in performance between the currently available brands of pads are subtle, and could easily take a back seat to such weightier considerations as price, size or the style of the mounting or interconnection system. This is not to say that there are no differences - as with any other type of equipment, the "try before you buy" rule is a worthwhile one to follow, especially since there's no learning overhead involved with pads (they all work the same). For example, you can be fairly certain that Simmons pads will work well with a Simmons interface, Dynacord pads with a Dynacord brain, and so on. However, you may find (we did) that the Dynacord pads are a bit shy in the trigger output level department when hooked up to other converters such as the Simmons - as just one example.

We also found some variation in the ability of pads to reject vibration transmitted through the stand from other pads on the same stand. It can be amusing to have your crash cymbal sample trigger on snare pad accents, but the joke wears off pretty quickly. Pads with floating batters, such as Yamaha and Dynacord, fared the best here. A pair of Roland PD20s worked side-by-side without a glitch, but both were triggered quite easily by strokes on a cowbell mounted above them. This has little to do with the trigger interface unit - with a single signal line from each pad, the trigger unit really has no way of distinguishing soft hits from stand crosstalk, and at most can only be set to reject all input below a given threshold level - which limits the available dynamic range of the system.

A notable exception to the above problems is the Roland Octapad, with its integral crosstalk-elimination system. Here, extra pickups are used to detect vibrations being transmitted through the frame, and cancel out this component of the signal coming from each pad. However, while the internal pads do not suffer from crosstalk between one another, the Octapad is in the same boat as all the other interface units when its external trigger inputs are used.

On a separate note, we found that some pads had a fairly even playing response at all points on the batter, while others were markedly more sensitive to dead-centre hits.

Other differences are more subjective. I tend to prefer pads which give the highest amount of stick rebound and make the least amount of noise of their own. Good rebound is helpful for playing technique, while low noise makes it easier to focus on the sounds being triggered by the pads, rather than the sound of the pads themselves, which by their acoustic immediacy can trick you into a perception of heightened dynamics (there's that crude mechanical glory again) if you're not using closed-back headphones or unethically loud monitors.

The Pearl cymbal pad is an oddity which rated somewhat poorly in both rebound and noise categories. No doubt inspired by the observation that crash cymbals are played by bringing the side of the stick down on the edge of the cymbal, as opposed to using the tip of the stick, the Pearl is set up to allow the same technique, offering a down-turned, semi-flexible plastic lip as the playing area. This strikes me (sorry) as a bit silly, since in contrast to real cymbals, the sound is gonna come out the same no matter how you hit the pad. And since it is indeed a pad which you are hitting, you might as well make the most of it - pads have much better rebound than crash cymbals and even most drums, especially those big deep ones with loose floppy heads - "floor toms", I think they're called. Besides which, it looks like a duck and gave the impression that it might break if I hit it hard enough (it didn't, though). On the other hand, it is smaller than any of the "normal" pads and better suited to being wedged into tight setups at odd angles, since you can come at it from almost any direction.

Yamaha's pad mount mechanism scores points for both ingenuity and ease of use. With one hand, you tilt and swivel the pad into almost any position, and then tighten a single knob with the other hand to hold it in place. (You are, after all, entitled to a little something extra in exchange for the higher price.) The more conventional mounting systems used by almost all the other contenders require the individual adjustment of at least one piece of hardware for each available degree of freedom. Adjustable indexing keys ease the task of later reassembly to exactly the same setup - or make it harder to change it around again.

There is, in fact, an alternative to using any drum pads at all - namely, using actual drums equipped with contact transducers or internal microphones. This is the sort of thing that dyed-in-the-wool drummers are inclined to do, especially if they go on-stage a lot, and even more so if the electronic sounds are being used mainly to supplement the sounds of the acoustic set - or if they just can't stand playing on pads and don't mind the additional noise and bulk.

"With these latest innovations, we have advanced beyond the point where it's necessary to speak in terms of 'programming' drum rhythms. Now you can just play them."

The Roland PD20 pads are a bit smaller than the rest, which is helpful for those (like myself) who think that eight pads is just kicking-off, 18 is in the penalty area, 28 is just about there... well, there are 32 sounds in my sampler.

But this alternative poses some problems which are not encountered with pads, the most obvious one being a major tendency towards acoustical crosstalk (less of a problem for the drums themselves, although the absence of buzzing snares on floor tom hits is a dead giveaway that you are not listening to an entirely live recording).

Another less obvious problem is that the audio signal picked up from a drum is often ill-suited for deriving triggers.

A well-designed pad is a heavily-damped vibrational system, in which the piezoelectric pickup acts as a sort of mechanical high-pass filter which responds most strongly to the initial impact of the stick. The result is that the trigger signal has a very clearly-defined single peak and dies away rapidly, so that even at closed-roll playing speeds, the signal spikes created by the individual stick hits are easily distinguishable from one another. Most interface units are designed to take advantage of this - each of their inputs can be re-triggered virtually as fast as MIDI can carry the note messages away.

On the other hand, drumheads tend to generate "dirty" attack transients whose real peaks may be hard to discern, especially at higher playing speeds, and the signal from a single hit may take a second or more to die away completely. The Simmons MTM devotes a hefty portion of its programmability to dealing with such inputs, using parameters such as "dynamic hold-off" and "percent above previous threshold" to bring things under control.

But with other interface units that are optimised for piezoelectric triggers, audio signal triggering can be expected to yield a sluggish response, irregular velocity sensing, and multiple triggering.

As If That Weren't Enough

AT LAST YOU sit with sticks in hand, gleefully swinging away at a veritable sea of pads before you - what are your feet doing? Holding up your legs? What a waste. Especially if you're used to including them in the beat-making. Your basic bass/snare/hi-hat rhythm is just a touch beyond what can conveniently be played with two hands. Laying this rhythm down into a sequence in two takes (eg. kick and snare in one take, hi-hat on the next) means having to do one of the following: 1) stick to a rigidly structured rhythm so that the different parts will mesh, 2) play what you feel on the first take, then carefully memorise and analyse the results in order to come up with a second take that fits well with it, or 3) just improvise on both takes, and settle for rhythms in which the individual parts may not work together in quite the way you had hoped (although the unpredictability can produce some interesting accidents, and a dose of chaos works wonders for breaking out of rhythmic ruts). It also means taking at least twice as long to record the same sequence.

But - especially if you have already mastered the hand/foot co-ordination - how much nicer it is to be able to play the entire rhythm at once, in the organic way, with freedom to improvise, and without having to really think about it all that much. (Here's that American jazz-rock mentality cropping up pretty strongly now.)

Bass-drum pads - the obvious extension to the basic pad idea - have been around nearly as long as drum pads themselves, and are generally just much larger versions of the same thing. This is because most drummers (apparently) feel naked and exposed without something large and bulky to obscure their legs from view. (All right, that was unfair. The bottom-heavy look of the traditional drum kit is quite visually appropriate to the sound it makes.) Only in the last couple of years or so has it dawned upon some manufacturers that a more compact item might be saleable as well.

The most extreme example of this is a unit from a company called Drum Workshop, which reverses the customary method of attaching a kick pedal to something else, and instead has a transducer mounted to the base of the kick pedal itself. The beater is readjusted to swing down towards the transducer, adding a bizarre visual touch. A low-profile metal and rubber plate provides solid support for the pedal and keeps it from sliding around, and that's it. You can't get much more minimal, though it's said that Terry Bozzio used to perform with a plain old footswitch as his bass-drum pedal - so much for live dynamics.

Just one size up, Dynacord offer a very space-age looking unit to which any standard kick pedal can be attached - this is more the ticket if you happen not to like the Drum Workshop pedal, or if you already have a kick pedal you like and don't want to fork out for a new one. It's just big enough to keep your foot out of sight, but weighs the better fraction of a bass drum -it feels nice and solid and you know it's not going anywhere. Uniquely, it also boasts an output-level selector switch for matching its output to the input characteristics of the interface unit being used.

Along similar lines, but at lower cost, the Techtonics Company has announced a unit (the Techtonics 2000 electronic bass drum) which closely resembles the Drum Workshop offering minus the pedal, allowing you to use the pedal of your choice - as long as you can set up the beater to swing downwards.

"Playing drum pads lets you do things you couldn't dream of doing on a keyboard, and the very feeling of swinging sticks against something can work wonders for your sense of rhythm."

Many of the available bass-drum trigger units and pads have dual connectors to make it easy to run two or more such devices into the same input on an interface - a simple path to the double bass-drum setup.

To those who may have wondered whether a full-blown bass-drum pedal is really necessary when there is no bass-drum actually involved, let me first say: "No, it's not really necessary". I'll also suggest, however, that a high-quality kick pedal is to the drummer's foot what a rebounding drumstick is to the hand - namely, a free-swinging lever extension of the body which, under proper control, allows the development of greater speed, power and precision, with less work. It becomes part of a physical feedback network which can help to stimulate further rhythmic expression. Which is more than can be said of most footswitches.

Waiting For The Other Shoe

FOR WHATEVER REASON, relatively little attention has been directed towards giving the "other" foot - the hi-hat foot - its rightful position in the electronic percussion pecking order. Perhaps it's because hi-hats, and cymbals in general, are such hugely expressive instruments whose sounds are more complex and difficult to reproduce than anything else in the percussion world (crude mechanical glory yet again). Even drummers who've completely abandoned drums in favour of pads still use real cymbals and hi-hats in their kits.

As the fidelity, bandwidth and recording time of samplers continues to increase, however, the canned versions of these sounds are becoming quite usable, if not actually respectable. Consequently, there is great annoyance on the part of drummers who are unable to apply their accustomed playing techniques to hi-hat sounds. For example, open and closed hi-hat sounds are typically accessed by assigning two different pads to them - a very unnatural situation for those who are used to doing it all in one place.

Recently, two units have appeared which feature similar solutions to this problem - ironically, at opposite extremes of the price spectrum. The Sequential Studio 440 sampler/sequencer and the Casio DZ1 pad-to-MIDI interface both allow users to designate a pad whose sound routing can be temporarily changed by means of a momentary footswitch - independently of other pads, and without resorting to program changes. They also include this all-important extra detail: closing the footswitch immediately triggers the sound which is active on the pad while the switch is closed (although at a fixed user-settable velocity, since the switch is not velocity-sensitive). This means (among other things) that a player can go from open hi-hat to closed hi-hat on one pad at the touch of a footswitch, and that closing the footswitch immediately cuts off the open hi-hat sound if it is ringing - a rough but workable approximation of the way real hi-hats work.

The appearance of this feature on the Casio interface is really the bigger news, since it can be applied to absolutely any drum machine with a MIDI input. (See Part 2 of this series, MT May '87, for a discussion of the features a sampler needs in order to exploit this trick.)

Meanwhile, in the Simmons camp, greater things are afoot (sorry again). The open hi-hat sound in the SDS7 drum brain can produce variable decay time by means of a VCA whose decay rate is subject to continuous live control (ie. it can be changed while the sound is playing). What this allows you to do is have one sound cover the range from fully open to fully closed hi-hats and a large number of steps in between. In addition, this sound can be suddenly choked off by jamming the control value all the way up. This control can be actuated by an assignable MIDI continuous controller, in addition to DC voltage control via an input on the SDS7 back panel - said DC voltage provided by the Simmons SDS7 hi-hat pedal. Trigger input 8 on the Simmons MTM can be programmed to accept the DC voltage input from this pedal and to convert it into appropriate MIDI controller messages - the advantage of this indirect approach being, of course, that these messages can also be recorded and played back by a MIDI sequencer.

Unfortunately, neither the SDS7 nor the hi-hat pedal were available to me - I must confess that here, I am relaying information from a Simmons manual which I have not had the chance to confirm directly (sigh). However, having long ago seen the same trick performed on the original SDS5, complete with its funky analogue hi-hat sounds and a continuous-control pedal which was also capable of generating velocity-sensitive closed hi-hat triggers when stomped upon, I have every reason to expect that it works just fine. And this is another big step closer to the way real hi-hats work. There are as yet very few drum brains or samplers which provide dynamic control of envelope times via MIDI, but this is bound to change as more manufacturers see the light.

And speaking of change - a large pile of change, to be exact - Simmons have announced yet another major innovation in what we Americans call the "player interface" department, which they have dubbed Zone Intelligence. Due to appear almost any time now on the company's new SDX system, this name refers to a hardware/software ensemble including special force-sensing resistor (FSR) pads, which can divine not only which pad you've hit and how hard, but also where the pad was hit. Specs for the finished system call for up to 16 separate zones on each pad, ideally in a concentric arrangement - which would again bring us a big step closer to the way real drums work.

The system is sufficiently sophisticated as to embrace a number of programming possibilities, but an obvious one is to give each zone a different sample. These could be samples of the same snare drum hit at various distances from the centre of the batter (or at various distances from the microphone, for that matter).

The zone system is said to extend to the SDX hi-hat pedal as well, allowing dynamic crossfading between multiple samples as the pedal pressure is changed. Killer.

The big question remaining to be answered is - will the concentric zones be circular or hexagonal?

And So...

WITH THESE LATEST innovations, we have more or less advanced beyond the point where it is really necessary to speak in terms of "programming" drum rhythms. Now, with only a moderate level of manual ability, you can just play them.

So sit yourself down, set your sequencer into Record mode (999 bars of 64/4) and go. Wind back to the middle and listen to what you were doing after a couple of minutes, when it started coming together. Pull out the good stuff, throw the rest away, and then go back and play some more.

Beats working.