Even a killer rhythm pattern won't make the grade if it's played with lacklustre sounds. In the concluding part of this series, NICHOLAS ROWLAND puts on his sound designer's head and explains how you can re-tread your tired timbres...

In the first instalment of this series, I made the point that one of the main attractions of sampled rhythm loops is often not the intricacies of the rhythm pattern itself, but the sonic character of the loop. This character might come from the particular ambience of the recording or the accidental presence of other instruments which add an unexpected twist to the drum rhythm. Or it might be there because someone has employed a whole bank of effects to flog the sounds to within an inch of their lives.

We've already looked at more extreme approaches to rhythm programming, in last month's issue. But in this final session of tub-thumping I'd like to talk about a number of techniques for manipulating drum and percussion sounds -- techniques which can be used to make even the most boggish of bog-standard drum machine rhythms sound that bit more interesting.

BREAKING THE STEREO BARRIER Many drum machines and sound modules are equipped only with a pair of stereo outs. Yet conventional rhythm track recording wisdom dictates that bass drums are recorded dry and snares have gated reverb applied, while hi-hats and other top-line percussion benefits from a touch of ambient reverb. If you can't multitrack the various elements of the rhythm separately to tape, sample the hi-hat parts with the necessary EQ and effects and run this loop alongside the bass and snare part, as supplied by the drum machine. Panning the snare and bass to opposite sides of the stereo spectrum allows you to then treat them with separate effects and EQ. Of course, when doing this you might want to consider applying the techniques mentioned elsewhere to the sampled part of the rhythm -- for example, recording at a low resolution or trying out the 'octave-apart' trick.

But first a disclaimer. What I'm outlining here is my personal armoury of techniques: I'm not claiming to cover the whole spectrum of possibilities. And remember -- parameter values can go down as well as up.

The first place to look for inspiration is in the manual. In other words, it's always good to know what your equipment is actually capable of (missus). Many drum machines and sound modules have various on-board facilities for customising sounds, such as programmable pitch, decay, and timbre. Some also give you control over such parameters as sample start point, velocity-controlled pitch-bend and velocity-sensitive crossfades between samples.

These parameters can be used in both subtle and not-so-subtle ways. As a simple example, you can add interest to a straightforward rock-style rhythm pattern by using different pitches of the same snare drum on different beats. Or try shortening the decay values on each successive beat of a snare fill, so that the sound tightens up as it reaches the climax of the roll.

Some drum machines allow you to spread a percussion sound across the drum pads so you can easily play it at different pitches. Rather than just tapping in a straight 8th- or 16th-note hi-hat pattern, with the voice at the same pitch, try programming in your hi-hat or other top-line percussion instruments (such as shaker, tambourine and so on) more as melodic riffs. (As an aside on tuning voices like conga and bongos, don't try and tune them to some precise melodic pitch -- somehow this has the effect of making them disappear from the mix.)

I mentioned last month that extreme tunings of sounds can yield some unexpected results. Yamaha's RX5 drum machine, for example -- a veritable giant of its time -- allowed transposition of samples over a staggering eight or nine octaves. You quickly discovered that at very low pitches electro-toms sounded like small explosions, while splash cymbals turned into J Arthur Rank-style gongs. Sadly, the designers of many other drum machines which offer tunable drum sounds see fit to restrict the pitch ranges to 'realistic' values -- a pity, really, as I don't feel you really get to know the true gut-wrenching potential of a vibraslap until you've heard it at subsonic levels.

Conventional wisdom dictates that when you place a drum sound in the stereo spectrum you should take your lead from how it would sound if you were standing in front of a drum kit. In other words, bass and snare dead central, hi-hat panned slightly to the right, ride cymbal slightly to the left, and the toms spreading from half-right to half-left in descending order of pitch. (Unless, of course, your drummer happens to be left-handed, in which case the kit placement would be reversed.)

These rules are all there to be broken, of course, though I would stress that panning effects are best applied only to sounds in the mid- to high-frequency range. As you probably know, it's much harder for the human ear to accurately pinpoint the directional presence of low-frequency sounds such as bass drums. Generally, then, gratuitous panning of bass sounds is a waste of time.

Where a rhythm has fairly busy high-frequency percussion elements (that is, hi-hats, ride cymbals, shakers and the like) try panning these elements hard left and right. This immediately opens up the soundstage and helps it to feel less cluttered. Extreme pannings of tom sounds can also work quite well in what, for want of a better phrase, we'll call 'jungle rhythms' (or, if you want the Politically Correct term, try 'tom-intensive ethnically orientated beats').

If you want to add a new twist to the machine-gun snare-drum rolls which usually come as standard issue with dance tracks, first program two rolls using separate snare sounds. Then either cross-pan them during the roll; start them at opposite ends of the stereo spectrum, then bring them together; or start them together and widen them out. Couple this with volume fades or changes in pitch to add extra "gosh" factor.

The above ideas are easy to apply if you're using a MIDI sequencer to control drum sounds from an external unit. With a fistful of MIDI Controller commands you can simulate ping-pong echoes, tempo delays and dub-style delay effects. (In fact, sequencers such as Cubase offer a MIDI delay program as part of the furniture.) Regard these features as your friends.

You can also create simple echo effects by copying a drum pattern to another sequencer track, then moving it forward by, say, a 16th note. You could then try assigning a different style of drum kit to this second rhythm pattern. If you were using a big-sounding rock kit for the main rhythm, you could try a softer jazz kit played at lower volume for the 'echo'. Obviously, you can take this technique a few steps further. For example, you could have a series of echo tracks built around just one element of the rhythm, with each 'repeat pattern' assigned to a different set of drum sounds.

If you're triggering a drum machine or sound module from a sequencer, you'll probably have noticed how doubling up the pattern (ie. sending the same information down the same MIDI channel twice) causes the double-triggering of the sounds to create a kind of phasing effect. This can be quite useful for giving flappy drum machine sounds a much harder edge. Try trebling or quadrupling up and see what happens.

The phasing ploy can be used to accent individual sounds, and is effective when creating big, bad bass drum sounds. If you want to go further down this road, try programming two bass drum samples on the same beat, but pitch one of them up by two or three octaves.

As a spin-off from the interest in analogue synths, there has been a revival of interest in the use of lo-fidelity techniques to give rhythm loops more roughage than a bucketful of All Bran. If this is the kind of territory you're interested in exploring, there's plenty you can do to dirty up your dance drums.

The basic advice here is to connect your drum machine through anything you think might distort the sound in some way -- guitar pedals, the filter section of an analogue synth with an external input... even a miked-up bowl of custard if you feel it'll create something interesting.

Effects treatments are an obvious place to start. Even budget units now offer various sound-crunching lo-fi presets. The Zoom 1201, for example -- at a mere £99 -- offers a number of 'lo-fi' settings, plus a vocoder. Effects plug-ins for programs such as Cubase VST are another useful tool for the grunge merchant on the prowl. Steinberg's Grungelizer and, more recently, the Trancemitter plug-in are worth a look, while the BIAS SFX Machine gives you a range of effects from radio tuning drift to ring modulation. One piece of freeware I've recently come across is Stephan Sprenger's North Po

"Try sampling (at low resolution) a beat-box rhythm at twice the tempo you need it, then play it an octave lower..."

le resonant filter plug-in for Cubase VST (for Mac users only at this stage). Go to http://www.prosoniq.com/ sms/sprenger.html for details of how to download.

There's also a range of external filters to suit every price and pocket, including the Mutator, the Sherman Filter Bank, the Waldorf X-Pole, the FAT Resinator and the wonderfully named Lovetone Meatball. Guitar pedals are also a particularly good source of mangle-isation. Not only are they comparatively cheap, you also get the added bonus of gratuitous hum, noise and distortion, particularly if you overdrive the inputs.

For the grunge programmer on a budget, there are a number of DIY options -- all part of general home recording tricks of yesteryear. For your own 'played down the telephone' effect, try running your mix through a low-pass filter set at around 3kHz with a little bit of resonance. Combine this with some sampled vinyl surface noise trimmed to the length of the drum pattern and triggered alongside. You can also try recording your drum machine through a miked-up guitar amp, preferably one with a dodgy spring reverb that's been dropped several times down a flight of concrete steps. Or record your rhythms to tape, then play them back on a portable cassette player turned up loud. Stick a microphone in front and enjoy.

Samplers provide another creative behaviour-modification tool. For a quick-fix lo-fi effect, try sampling your drum machine pattern at a low resolution and then trigger it from your sequencer as you would a loop from a sample CD.

If you know your sampling maths, you'll be aware that when you play a sample an octave higher than its original pitch, the sample is in fact running at twice the speed. And conversely, if you play it an octave lower it runs at half the original speech. So try sampling (at low resolution) a beat-box rhythm at twice the tempo you need it, then play it an octave lower than the sample key it was assigned to. The result is a detuned version of the rhythm running at the correct tempo. Obviously, you can play around with the tempos and sample playback speeds to arrive at different combinations of these tempo/detuning parameters. If anyone has a mathematical formula for determining the precise results of this approach, I'd be glad to hear it.

When sampling your own loops, it's a good idea to always apply some kind of effect during the sample recording process -- reverb, chorus, flange, distortion, EQ, filter. Basically, what we're interested in is messing up the frequency content a little, to try and blur the edges of the original drum voice. Once you start pitching the rhythms up or down, the results will be that much more interesting.

Clearly, you can apply this basic technique to entire rhythms or just sections of them. For example, you could investigate the potential of sampling the hi-hat and top line of percussion, then running that as a detuned rhythm loop against a bass and snare pattern provided by your drum machine/sound expander.

Another technique related to the one above can be used to produce ethnic-sounding, lo-fi percussion tracks. Again, this trick is based on the fact that samples played an octave higher run at twice the usual speed. Let's say you sample a rhythm loop on middle C. Now play it back using the G below and the G above. This works particularly well with patterns made up of latin and hand-held percussion -- bongos, congas, shakers and so on. You usually end up with a plicky-placky percussive line at the top and a heavy-sounding tom tom-style beat running underneath.

If you want to add a touch of real-life ambience to your rhythm tracks, as well as bringing in all that touchy-feely human stuff I was banging on about in the second instalment of this series, why not record part of your rhythms live, using real instruments? While I recognise that most people don't have the luxury of a full drum kit to call on -- or, indeed, the kind of neighbours who would tolerate the noise -- it's relatively simple to add percussion parts to bass/snare rhythms with tambourines, shakers, maracas and other instruments. You might even consider vocalising these sounds. Providing you're not the sort of person who feels self-conscious going "tss-te-te-tss-te" or "che-che-che-che" into a microphone, you might find you actually enjoy it. In one memorable (and, I have to admit, drunken) session, a friend and I once partnered a drum machine pattern with the sound of cutlery being shaken in a tambourine and recorded through a guitar pedal flanger. But we've both had treatment for it now.

Clearly we're beginning to stray into territory normally inhabited by fresh-faced Blue Peter presenters, but just before we fall into the abyss, I might as well encourage you to raid the kitchen for pots, pans, glass jars and bags of rice, with which to construct makeshift rhythm instruments. Just make sure an adult is present whenever you attempt to use the scissors.

And there you have it. Go forth and make beauteous beats. I'm off to watch that old Blue Peter episode where John Noakes makes a drum machine dust-cover out of squeezy washing-up-liquid bottles and a length of sticky-backed plastic.

© 1998 Sound On Sound Limited. The contents of this article are subject to worldwide copyright protection and reproduction in whole or part, whether mechanical or electronic, is expressly forbidden without the prior written consent of the Publishers. Great care has been taken to ensure accuracy in the preparation of this article but neither Sound On Sound Limited nor the Editor can be held responsible for its contents. The views expressed are those of the contributors and not necessarily those of the Publishers or Editor.