Steinberg SpectraLayers Pro 8 £257

The audio waveforms shown in DAWs and other audio tools map amplitude changes over time, which is easy for a computer to create and easy for a human to read. They say nothing about the frequency content within a sound, though. This is where spectral editors come in. These allow us to see the constantly-fluctuating frequencies within a passage of audio and, more importantly, they allow us to edit specific frequencies and frequency ranges. This makes spectral editors well-suited to corrective tasks, although they are also powerful sound design tools, and so these are the use-cases that Steinberg have focused