Creating and manipulating drum loops - Part 1

A little sample manipulation and processing can help create the perfect drum loops for your songs. Ian Waugh wields the scissors and the paste pot...

Drum tracks form the core of many modern songs. While there are thousands of off-the-shelf drum loops and samples, you may still not find exactly what you're looking for. You may have found a loop with a great kick drum but prefer the snare from another loop. Maybe you like the sounds in a loop but the groove isn't quite right. And if you do chance upon the perfect loop, you still need more patterns for the intro, fills, verse and so on. In this feature we'll see how to create your own loops and modify existing ones to create the exact sounds and grooves you need. The principles we discuss can be applied to any type of music.

If you know the exact drum patterns and drum sounds you want for your drum track then you've a head start on the rest of us. Your task is to select suitable drum samples from the three million available on the Net and CD (or record your own), and assemble them into your perfect track. This is often easier said than done.

Stick together

Let's look at the drum sounds first of all. You usually want the drum sounds to have a cohesion within the drum track; in other words the drums should sound like they fit together, are part of the same drum set and were recorded in the same environment.

If you are going to pull together samples from several different sources, they may not have this cohesion although, to a large degree, this depends on what you want from your drums, and on your music sensibilities. The main problem tends to be with drum samples that have had effects such as reverb added. A dash of reverb can make a single snare shot sound wonderful but if you try to use it in a pattern with other drums it may not fit. For example, you may need to cut into the reverb with another drum hit or the ambience on the snare will not fit the ambience of the other drums. So when choosing individual drum samples, you will usually achieve more cohesion by using ones with no effects - they are, after all, easy enough to add later.

Also, you generally want the drums to sound like they came from the same stable. This may be a little subjective - you could probably mix and match drums from different makers' kits without too much brouhaha but the scope for mismatching is much greater with samples. It's easy to pick a collection of drums you really like only to find that the snare is too low, perhaps, for the kick drum, or the cymbals ring too much for your Dance track. In any event, whenever you find a sample you like, store it for future use. To get a feel for the drums in context, put them together in a pattern and see how they sound. We'll do this in a moment but first let's consider the cohesive problem with loops.

Sample loops are self-contained drum patterns generally made up from a cohesive set of drums, sometimes complete with effects. The problem here is that you find a great loop for the chorus but what about the verse, the intro, the middle eight and the fills? Unless the loop comes from a sample CD continuing all the 'extra' bits created from the same samples then you may struggle to find other sample loops in the same vein to fit other sections of your song. We see how to do this shortly, too, but first let's see how to create your own patterns from individual samples.

Voice of the machine

There are two ways. The first is simply to drop individual samples onto tracks in a sequencer to create a drum pattern. This can be fiddly as you could well be working with snap values of 1/32nd of a beat - or less! - which also makes it tricky to experiment by changing the samples or, indeed, the pattern itself. Far easier is to use a sampler or a sample-based drum machine such as Battery, LM4 or the DR-008. Load in the samples and play them from a MIDI keyboard. Playing live gives you a particularly good feel for the sounds, even if you can't quite master the pattern you eventually want to use.

Alternatively and in addition, you can create MIDI drum patterns in a sequencer and use them to trigger the samples in the sampler or drum machine. If you do this, when you load new samples you will, of course, have to ensure that drums of the same type go into the same slots so the snare drum line isn't suddenly being play by a hi hat. Using a sampler in this way allows you to quickly and easily audition many samples, see how they work together, and save any collections of drum sets that you think are interesting and worth keeping.

The drum tracks for many types of music sound better if you add a splash of reverb. This is easy to do if you're playing a virtual sampler or drum machine through a sequencer, for example - simply add the reverb at the output stage. Again, this helps you appreciate what the final sound might be like.

Zero crossings When creating loops, you must consider zero crossing points. These are places where the audio waveform that you see in your audio editor crosses the horizontal zero line. At these points the amplitude is zero so cutting and pasting at these places will minimise clicks and glitches might occur when the loop repeats. Most audio editors have a zero crossing function which ensures that all cuts you perform on the audio take place at a zero crossing point. It's a good idea to keep this feature on when creating loops. But before you raise the scissors, run the editor's DC Offset function. This checks that the waveform is centred above and below the zero line and corrects it if it isn't. If it's not, then edits will not be performed at a true zero crossing point. See our Sample Editing feature in the last issue for more about audio editing and zero crossing points.

A peg to hang your loop on

Although you can record your own samples and making your own loops (see side panel), most people probably start their search for good loops with a walk through sample city - loop CDs - in the hope of finding something ready-to-go 'off the peg'. If the question of originality bothers you, worry not because you can still customise commercial loops to add your own musical stamp to them.

But there are two potential problems with off-the-shelf loops. While many sample CDs offer a range of loops created from the same sounds - thus ensuring cohesion - the patterns may not cater for all the variations you require. You may have discovered a fantastic groove, ideal for the chorus, but is there a slightly lighter version for the verse, Are there suitable intro, middle eight and ending loops and do any of them contain that magic sprinkling of percussion runs around the kit for the drum fills? In most cases the answer will be No. And even if there is a selection, you'll either have to be very lucky or very easily pleased to find so many patterns which slot perfectly into your song.

The second problem is that the groove may be superb but one or two of the drum sounds are not ideal. If only you could change them. Well, you can with the aid of software known as beat slicers. These divide a loop into its individual hits and allow you to perform such miracles on them as was never before imagined prior to the development of digital editing.

 

Burning ACID loops Users of Sonic Foundry's Acid can use Sound Forge to create loops with special properties for use in the program. The first stop is the Edit Acid Properties window where you can set the sample to be played as a Loop or a One Shot. Loops can be given a root note for transposition although you probably won't want to transpose drum loops.  You can set the tempo for the loop and with Acid 3 and higher you can also set a root note for transposition. There's a downbeat offset for loops whose downbeat is not at the start of the sample.  Other Acid options include doubling and halving a section, the ability to shift a selection to the left or right, and rotating the audio which moves a selection from the start of the loop to the end or vice versa. Of course, these functions can be used with any loop, not just those designed for Acid.

Slice and dice

The first beat slicer was probably Steinberg's ReCycle, developed by Propellerhead. Other programs you should look at include Button Productions' Zero-X BeatCreator and Native Instruments' Intakt. Using ReCycle as our example, the program looks for peaks in the audio waveform and positions markers at those points. As software is not yet intelligent enough to be able to extract individual drum sounds from an audio file, the program is simply marking 'hit' points rather than individual drum sounds but this, as they say, is near enough for jazz. You can change the sensitivity of the peak selection, add and remove markers manually (for those quiet hits the program will inevitably miss) and you can lock markers into position to make sure specific hit points are not removed.

Once a loop has been sliced into its component hits, they can be moved, edited and processed in all manner of ways. One of BeatCreator's most interesting and addictive features is the ability to rearrange the slices - and the most oft-used button in this section is undoubtedly the one marked Random. It's amazing how many musical and downright groovy grooves can be created simply by shuffling around the existing hits in a drum pattern. Not all hit the mark - sorry! - but it would be surprising if you didn't discover a least a couple of good alternative loops with this method. You can also move slices manually, taking the element of serendipity out of the hands of the muse, and there are options to mute slices and replace them so you have a lot of control over the loop creation process.

BeatCreator has several other excellent features such as the PCP (Pattern Controlled Processor) which lets you apply a range of filter, EQ, overdrive and reverb effects to the slices. The Slice Processor processes each slice individually, applying various filter controls to them, and it has the all-important Random button, too.

Virtually all slicers have a reverse function and you'll find this in most audio editors, too. You can use it create the infamous reverse cymbal effect, but in a slicer it can be applied to individual slices within a loop which can create some distinctive patterns.

While you can slice up loops in a sequencer or audio editor and do your own processing and manipulations, slicing software makes the process much easier. If you have a busy chorus pattern, you can create less-busy patterns for the verse by muting some of the slices. If the busy pattern has, say, two hits on the third quarter beat, you could mute one or remove them both and substitute a slice containing a single hit. In this way you can create alternative patterns from a couple of loops and maintain cohesion between all the drum sounds. Of course, you can still be off-the-wall and throw in an oddball drum sound every now and again if you wish, to add interest to the pattern.

Rolling your own The die hard sample aficionado will want to do everything from scratch, including recording their own samples. All the usual recording rules apply here - make the best, cleanest recordings you can, as loud as possible without distortion. You can sample a range of sounds, not just drums, and then process them to sound like drums. For example, boxes whacked with sticks, or cups and glasses gently tapped can be processed with envelopes, EQ'd, time stretched and pitch-changed to create a range of drum-like sounds. Many rhythmic sounds can be processed and manipulated and pressed into service as a 'drum' loop. Try anything that clicks or clangs, washing machines, spin driers, run your nail over a computer keyboard, a grill or sieve... If you are recording your own loops, here's a couple of tips. If the sound has any ambience - maybe you're running a loofa over the radiator in the bathroom - make the recording at least twice as long as you need for the loop. Then to create the loop, use the last half of the recording. This will that any ambience at the end of the loop is included at the start of the loop. Otherwise each time the loop, er, loops, the start may sound dry in comparison to the rest of the loop.

 

Ian Waugh
Read More of Ian's music reviews and tips at www.making-music.com