Drum mapping can really baffle, and sometimes exasperate, musicians trying to learn MIDI-computing.

First of all, the General MIDI specification includes 128 percussive sounds. Each one is identified by a specific key-number on the master-controller keyboard, as well as by a note name, like G-3. If this were the end of it, the bafflement could be limited, but such is not the case.

Synthesizers have multiple drum kits in their mysterious chips. One sound card can be accessed in two modes: General MIDI or Proteus, the latter of which offers additional drum kits, (e.g., Latin sounds). A popular sound module provides six drum kits, two of which are available for us to construct--choosing from 114 drum sounds.

Having mentioned these inhibiting threats, I would suggest that we forget about them, at least for purposes of this publication which is, after all, about making music, not about microchip technology. Thus, we will confine our comments to the drum sounds available in the General MIDI specification.

Happily, sequencers provide many features that can reduce the anxiety of wannabe drummers. As a matter of fact, the task of producing and improving complex rhythms can be approached from various directions. The grizzly expression, “More ways to skin a cat,” seems to apply to MIDI-computing, where one can use this feature, or that, or the next one...

And so it is with drum sounds.

You gain considerable insight by calling up the keyboard display, the score window, the event list, the piano-roll window, the track listing, the mixer, and the drum view (if there is one). As your insight increases, you can identify the strengths and weaknesses of the percussionist's performance.

Consider the keyboard window.

Since General MIDI drum sounds (in nearly all cases) are associated with channel 10, make an effort to enter this channel in the display. Can you find middle C? This is keynote number 60. You should hear the sound of a high tom drum. [Increase velocity, if necessary.] Search for the crash cymbal (A-2, note #56). You are welcome to meander among these percussive sounds to your heart's content, or at least until you get the feel of (a) what they sound like, (b) where they are located on a keyboard.

If your sequencer has a Drum View, it will show about 50 sounds to play with, from an acoustic bass drum to an open triangle. Tools for editing are available, such as inserting or deleting sounds according to their note-length (whole note, half, quarter, etc.) The existence of these notes is also verified in the event list--including the names of the sounds. There they are again in the score window and elsewhere.

Anyone serious about music is aware that a percussive performance can range from the complexity of timpani patterns in a concert work to a relatively simple bongo-conga beat in a jazz arrangement. Simple and, hopefully, tasteful. How in the world do we learn how to improve such drumming? The cliché comes to mind: Practice, practice, practice. In sequencing we have another means of improving: listen and look! In other words, study a well-played percussion line in a successful sequence, slow down the tempo if necessary, then emulate it. This advice goes beyond the traditional “Just listen,” because we now have, in the sequencer, sounds and pictures--a whole range of vivid displays.

Without presuming to suggest the techniques of a professional percussionist, one can recognize a few hazards in the process of sequencing drum sounds.

We start with a dilemma. Sample drum tracks can be obtained from a variety of archives: drum fills, solos, rock style, shuffle, swing, samba, etc. These samples are often quite short, a few measures at most. So, how does one adapt them for a full-fledged MIDI sequence? The answer: Loop them. Copy and paste. Certainly this process is convenient, but it also risks creating something that sounds repetitious, monotonous, tedious.

In live bands (jazz, rock, country, etc.), competent drummers do not play this way--for the entire length of a song. Of course, they are expected to keep a steady beat, but they play a range of drums: closed hi-hat, side stick, acoustic bass drum, hi-mid tom, a snare, a wood block, a cow bell... In an unpredictable fashion, creatively.

This comment is intended to suggest one of the most common percussionist errors of MIDI recordings. Regrettably, they sometimes sound like an old-fashioned “side man” for a jazz musician. In a word, painfully “mechanical.” Again: Listen, look, and emulate the professional--not the machine.

In our earlier discussion of pitch, it was suggested that instrumental tracks might be transposed, while leaving intact the percussive track. Under some circumstances, however, one might want to include drum sounds in key-transposition in order to change the rhythmic patterns of an arrangement. If a drum track is imported from an accompaniment program, or is created de novo by the user, changing the song key (say, from C-major to Eb or F-major) will shift the drum map to new percussive sounds. You can see such a shift in various window displays, like the score window.

Assume a 3-chorus swing drum map with such events (in the first chorus) as closed hi-hat, side stick, acoustic bass drum, open hi-hat, etc. When you move to a new key (Eb) in the second chorus, and include the drum track in the transposition, percussive sounds will change. The acoustic snare might appear, the electric snare, a low tom, a crash cymbal. And when you move to F-major in the third chorus, you may hear (and see) the tambourine, ride cymbal 1, a high tom, etc. What has happened, of course, is that, in the transposition, you have changed the assignment of drum-key numbers.

Like many of the procedures suggested as a means of improving a recording, quantization is something you might want to try, experimentally. The same for its reverse, humanizing. The former procedure forces all notes played to fall on the nearest time-interval specified. The latter introduces random irregularities in event timing and velocity.

Having said this, I must confess that I have had meager success with either procedure as a means of enhancing a recording. This may well be attributable to my predilection toward jazz, which achieves its fluidity from syncopation--apparently an anathema to the quantizing process. Perhaps you will enjoy more success. My gratuitous advice: Try.

One last observation about drum tracks. Most sequencers give you the opportunity to split them by instrumental sounds. This action may provide more elements (drum sounds) than you care to examine under your microscope. But it is another perspective. For those with insatiable curiosity.

Copyright © 1995 Eugene A. Confrey, PhD. All rights reserved.