Making Music
  Computer Music Software and Hardware

Put it another way...

Reverse is a very old effect but deserves a mention because we can bring it bang up to date. The process itself simply reverses a waveform so the sample plays backwards. It's an interesting effect, atmospheric with vocals (and Black Sabbath fans) and useful for creating special sample effects. It's also the core of the reverse cymbal effect so widely used, still, in Dance music to lead into the start of a section. If you like reverse cymbals it's worth running some of your favourite cymbal samples through this.

We can give the reverse effect a twist by reversing a sample, applying an effect and reversing it again. What this does is to give us a reverse effect that leads up to the main sound that created it. Don't think about, try it! Heavy reverb, for example, creates a sort of backwards effect so we start to think the sound is being played backwards but then we hear the sound correctly so we think it sounds likes it's coming from down a tunnel but we don't really know what the heck we're hearing! Such effects are commonly used in the movies to create a disorienting ambience.

What's normal

Normalisation increases the amplitude of a signal to make it as loud as possible without distorting. This is useful to help balance different tracks when assembling them for a CD or simply to increase the loudness of a quiet track. However, you need to be aware that normalisation will increase any noise as well as the signal, which highlights the importance of making good recordings in the first place.

Normalisation works by scanning the file for the highest peak in the signal, subtracting this from a level of 0dB and then increasing the total waveform by that amount. Many editors let you vary the scale of the increase so you can decide not to do a full normalisation, say if the noise level is too high. You can normalise greater than 0dB which will result in clipping although this may be acceptable if the peaks are only a transient pulse or two, or if you particularly want a soft clipping/distortion sound.

When normalising a stereo file you should ensure that the two channels retain their relative amplitudes. WaveLab's Stereo Link function scans both channels to find the maximum peak but applies the same level of gain to both.

Getting converted

Finally, there's the Resample or Sample Conversion function that converts one sample rate into another. If you want to use a collection of samples of different rates in a project, it may be necessary to use this to convert them to the same rate. Note that increasing the sample rate will not increase the fidelity of a low-quality sample - essentially you're just using more disk space to store the same crap sound - but some sequencers and editors need all the audio files to be the same format so this may sometimes be necessary.

If you work at 24-bit you have to downsample to 16-bit for burning to CD. This is best done with a dithering algorithm such as that found in WaveLab and Cubase, and Sound Forge and Adobe Audition also have several dithering options. There are no optimum choices here - the best settings will depend on the material so you need to experiment.

The basic edit functions of modern audio editors are essential tools for anyone working with audio, particularly samples. Get to know how they work in your editor of choice and make your samples better fit your music.