Now we'll put the theory from Part 2 to use. Our step-by-step example for using a breakbeat starts here. Actually, I'll start by taking a step back, so make sure you download the appropriate files if you want to follow this properly.

Trimming

Check it out.^ Here is a screen-shot from the classic audio editor, Cool Edit Pro (more recently upgraded and repackaged as Adobe Audition). In this image, hattrixx-example-1.wav is playing in loop mode. If you don't have the file saved already, right-click here and select 'save as', so that you can open it in your audio editor. Notice how what you hear and what you see are 4 bars of the same loop.

Focusing on just the waveform itself, I've highlighted (^in green) where the first kick drum and hi hat take place, to indicate where the 1st beat starts each time. We're going to start by cutting the sample down to just 1 bar, discarding the repetitions. To do this, you need to decide which 1 of the loops you're going to keep, and find where it starts and ends on the waveform. Why is this important? Well, I would strongly advise against using the first or last loop of the sample, because this will make it more difficult for you to make sure you have a smooth and accurate loop. So pick one of the middle 2 loops, and highlight to isolate it very roughly.

It is vital, at this stage, to ensure that you have selected more than the loop you want to isolate, not less. ^The image above clearly shows how I've selected from just before the loop, to just after the loop. You should be able to see that my selected area begins just at the tail of the last hit in the previous bar, and just a small amount into the 1st hit of the following bar. If you try to play this selection in loop mode, it will sound horribly inaccurate. Right now, that is exactly what we want.

From here, there are 2 methods that work with nearly all audio editors, to home in closer on our target loop. The first is to use a dedicated 'Trim' tool (found in the Edit menu on Cool Edit Pro), to isolate the selection. Or, without such tools, I have a second method. Just use the 'Copy' tool on the current selection, then 'Select All' or 'Select Entire Wave', then 'Paste' to replace everything with just the initial selection. You should end up with something resembling the image below. 

^Yes, that's what it's supposed to look like. Now we have everything we need to cut more accurately and achieve the smoothest-sounding loop possible. Why is that important when an inaccurate loop can sound just as good? This is what we're about to find out. 

^Above is Cool Edit Pro's representation of a 'zero-crossing'. The next step for us is to find a 'zero-crossing' on our breakbeat. A zero crossing is the point at which a waveform crosses the zero amplitude mark (the red line in the image above). In reality, almost no digital sample is going to fall exactly on the zero amplitude mark, but zoom in as far as necessary to get as close to a 'zero-crossing' as possible.

The reason for taking a couple of extra seconds to find the 'zero-crossing' is quite simple. In the real world, all sounds we hear begin at zero volume. The initial attack of the sound might be extremely fast, but the start is always zero and creeps upwards in amplitude. In the world of sampling, it is quite possible to start a sound with an immediate attack. This creates a nasty, unnatural clicking sound. Ensuring that all of your samples start as close to the 'zero-crossing' as possible will help to create an overall smooth sound, that is easy on the ears. Also, be aware that the attack of a drum hit is going to start at zero amplitude, so if you're looking for the origin of an individual hit, you will find it at a 'zero-crossing'.

Click here to download a quick example video, demonstrating cutting at the zero-crossing.
^Notice how in the video, I've cut the sample as close to the 'zero-crossing' as possible.

The Post-Trimming Phase

To progress, simply make sure you have trimmed the sample at both ends, and it loops nicely. The 2 zero-crossings on my provided example breakbeat will look identical, since the loop is a digital clone. When you have a smooth, accurate-sounding loop, you will be able to count the number of bars (in this case 1). Which leads us back to the BPM calculations.

FORMULA FOR FINDING THE TEMPO (BPM) OF A SAMPLE:
Step 1) Find the number of seconds the loop lasts, and write down the number.
Step 2) Find the number of beats the loop lasts, and write down the number.
Step 3) Divide the number of seconds by the number of beats, and write down that number.
Step 4) Divide 60 by the result from Step 3. Voila - now you have your BPM.

FORMULA FOR FINDING WHAT LENGTH TO STRETCH (IN SECONDS) YOUR SAMPLE TO:
Step 1) Divide 60 by your destination BPM. (For example 60 ÷ 120)
Step 2) Multiply the result from Step 1 by the number of beats you have. Tada! You now have the length in seconds of your sample at your destination BPM.

For this example, I want the loop to run smoothly at 135 BPM. The source tempo in this case is irrelevant. I know that I want the sample to last for 4 beats at 135 BPM, so I just need to find the length (in seconds) to stretch the sample to. The Windows calculator (found in 'Accessories') is handy for this!

60 ÷ 135 (my destination tempo) = 0.4444
0.4444 * 4 (my destination number of beats) = 1.7778 (my destination length in seconds)

For simplicity, I've rounded the figures to the nearest 4 decimal places. Cool Edit Pro has a 'Time/Pitch' menu under 'Transform', which leads to the "Stretch..." screen below.

Now, obviously some of you won't be using Cool Edit Pro. I just want to make it clear that the stretch is to be achieved using the length in seconds only, and that you do not preserve the pitch. Why not? Well, time stretching is a complicated business, and drum loops are perfect for exposing the flaws of time stretch algorithms. Besides, I'm covering the essentials now, and will be explaining how you can alter the pitch of the drum hits independent of tempo later on in this guide. For now, it's better to learn these more traditional techniques.

You should now have a smooth, 1 bar loop at a tempo of 135 BPM.

Click here for one I made earlier.

Cutting & Splicing

I can imagine at this point, that not all of you are going to immediately accept the methods I suggest in this section. I encourage you to have some trust and patience. Later on, when I refer back to this section, you'll understand why I'm explaining things in this order. First, we'll be choosing cut points that will allow us to splice the breakbeat into re-workable segments.

Don't worry, you haven't been eating too many sweets. ^I've coloured different sections of the breakbeat to roughly indicate my chosen cut points. The blue section starts with the kick; the green section starts with the first snare; the yellow section, a distinct hi-hat shuffle; the orange, a smaller hi-hat shuffle; and the red section is just that metallic-sounding snare at the end. I've chosen these points by watching the play cursor, while listening out for those distinct elements.

We're about to make our cuts. Here, you do not cut what follows each of the chosen cut points. Only cut what precedes each of the cut points! I have chosen 5 cut points, A through E, so we'll be saving 5 separate files, each one shorter than the last. The first file to save is the full 1 bar loop. To make things easier, I often use a simple naming convention. So use the name of the breakbeat, followed by it's tempo and a letter to indicate the segments' placing. I've dubbed this the "dreambreak" since the image above reminds me so much of Joseph's Amazing Technicolour Dreamcoat. Next, find the zero-crossing at the start of the next cut point and remove what precedes it, saving as segment 'B'. Remember to check that each cut sounds good before you save it, by playing it. If it doesn't, look for another point that's close to the zero amplitude mark. And so...

Cut A: dreambreak135A.wav
Cut B: dreambreak135B.wav
Cut C: dreambreak135C.wav
Cut D: dreambreak135D.wav
Cut E: dreambreak135E.wav

As you can tell, each segment plays from a different point in the bar, but they all play to the end of the loop. Where to make the cuts start depends on what you want to achieve when you're retriggering. In this case, I decided the 1st and 2nd snares weren't different enough to warrant separate cuts. If I want more cuts when I come to sequence, I'll create them later. The 5 cuts I have chosen will be more than enough for what I want to achieve.