Before using samples that we have downloaded or created, they should be prepared for use in our sequencer.

Normalise

When a sample is normalised Audacity increases the amplitude of the sample to it's maximum without altering the waveform. This is useful because it maximises the dynamic range of the sample. If all your samples are stored normalised you will avoid noise problems later on.

In Audacity select the whole sample, click Effect -> Normalise and OK with the default options.

Trim

It's best if the samples don't have quiet sections at the beginning or end. You can select the part you want in Audacity and click Ctrl-T to remove the parts outside the selection. Be carefull not to trim off any important sounds like a faint echo or reverberation.

Sometimes using Trim is too abrupt - the sound is cut off too sharply and sounds wrong. In this instance use Fade In and Fade Out. Experiment by selecting the first or last part of your sample and click Effect -> Fade In or Effect -> Fade Out. Sometimes a long fade is good, sometimes a very short fade like a soft cut - it depends on your sample and your taste.

Noise removal

Generally it's best to start with clean, undistorted samples with little or no background noise. Later on when you start to mix the sounds to create your tune, high-quality, clean samples will make a big difference to the overall quality of the finished product.

Sometimes it's not possible to find a clean sample and Audacity provides some facilities to remove noise and clean up samples, but a cleaned-up sample NEVER sounds as good as a high-quality noise-free recording to start with.

The noise removal effect in Audacity works well for samples which are sparse with gaps between the sounds, like a drum beat or vocals, but where in the gaps a hum or crackle is audible.  This nioise is often introduced by low quelity recording equipment or when sampling from old vinyl records or cassette tapes. The hum or crackle is called noise and if the noise is constant throughout the sample, Noise Removal can make a startling improvement.

EQ for cleaning

If your sample has a high-pitched whine or a low rumble you can clean it up using Equilization or EQ. Select your sample, and click Effect -> Equalization. Click on the blue line at 30Hz and again at 300Hz. You can now drag the 30Hz end of the blue line down creating a ramp. When you preview your sample you can hear that the bass is almost all gone. By adding points and dragging them around you can see which parts of your sample appear and disappear. It's a great way to learn about pitch and frequency!

There is a rule in using EQ - never boost only cut. This means that no part of the sample should be made louder by EQ just the parts you don't want made quieter to avoid distortion. Once you have clicked OK to apply the EQ you can Normalise the sample to bring it back up to maximum volume level.

Other effects

Audacity has a whole list of other effects - feel free to play around with them and see what effect they have on your sample. However it is usually best to leave effects like reverb or phasing until later in the music making process. The programs you will use to make your final tune have all these effects and more. Once you have added an effect you can't take it off, so let's start the music making process with your nice clean trimmed loops and samples with no effects added yet.

Example

This is an example of a very noisy sample. To clean it up we used:

1. Noise removal
2. High pass filter (EQ)
3. Normalise