Spectrum analysis
Spectrum analysers are the easiest analysis tools to use and probably the most commonplace after level meters – so much so that they were once a regular feature on home hi-fi equipment. This is mainly because they looked pretty as they bounced around in time with your music. Oldfashioned spectrum analysers break the signal down into a series of frequency bands and display the levels (typically average and peak) of each band independently.
More advanced modern software versions display a continuous curve, representing all audible frequencies. Most DAWs have a built-in spectrum analyser either in the EQ or as a separate plugin. Alternatively, check out commercial options such as Nugen Audio’s Visualizer (www.nugenaudio.com), which includes many of the tools discussed here.
Analysers can be put to a range of uses during production. Primarily, they can be a visual aid for EQ and mixing challenges. The frequency range of a sound can be quickly identified to determine where it sits in comparison to other elements. Unwanted low- or high-frequency content can be identified and the response of the entire mix can be analysed and compared to other tracks to see if it’s hitting the same frequencies as a good commercial mix.
A further variation on the spectrum analyser is the waterfall diagram, which introduces time on a third axis, creating a three-dimensional graph of how the level of each frequency band changes over time.
Spectrographs (often referred to as spectrograms after the name of the diagram they generate) are tools that produce a twodimensional representation of the same data shown in waterfall diagrams. Rather than using a third axis, spectrograms typically represent time along the x-axis, frequency up the y-axis and level using colours. Many people find them easier to read than 3D waterfall diagrams.