6. SPAN Plus
Although SPAN is one of the most fully featured free plugins you’re likely to come across, it does have a more powerful commercial sibling in the shape of SPAN Plus, which costs $40. There are quite a few reasons to upgrade, but without doubt the main one is the ability to feed every instance of SPAN Plus running in a project into every other, for simultaneous analysis of multiple tracks in a single window.
Using the Import/Export Settings panel, each instance of SPAN in the project can have its spectrum ‘exported’. Every exported spectrum then appears in the Import list for every instance, enabling each one to show your choice of up to five ‘exported’ spectra at the same time. Every spectrum retains its settings as established in its source plugin – colour, Mode, etc – and with up to 48 Export slots available, you certainly won’t fall short in terms of track coverage.
Also handy in SPAN Plus are the abilities to save the spectrum as a PNG image file at the click of a button, and instantiate up to four static spectra in the Spectrum Analyser, for comparison to the live signal. These can be grabs of the main or second spectrum, or one of six predefined noise and weighting curves, and you can save and load your own static spectra, too. Each of the four statics can be assigned its own colour and boosted or attenuated by up to 32dB either way.
While the free SPAN more than meets the needs of most computer musicians, if you’re really serious about your signal analysis, SPAN Plus is well worth investing in.