ChordLab has been around for many years and is about as niche an app as you can get - a chord calculator for four-part harmony, voice leading and arranging in general. This is not an app for the novice or beginning instrumentalist. It is not a chord book app. It might, on the other hand, hold interest for Jazz guitarists, pianists and arrangers. It depends on the arrangement of course, but four-part harmony with appropriate voice leading is a solid choice.
Changes is a term coined for the "changes" that voices undergo in harmonic support of a melody and bassline possibly. In that an economy of voices, be it three or four at the most, has served as a stylistic as well as practical approach to harmonizing or accompanying. And this is the context in which ChordLab can be quite useful and maybe serve as inspiration for some more unique chord choices. No more chord spelling, just punch it up and put it through the motions.
The basic calculator function spells a chord defined with root and quality - like Abmaj7. Additional operations allow the application of inversions as well as common drop voicings and results are shown in music notation as well as note locations on the current instrument. With 16 different guitar tunings this can come in quite handy when putting together a bunch of new background harmonies.
The latest version of ChordLab for macOS streamlines the interface a bit while improving overall functionality. ChordLab has gained a new look - in the dark that is - and improved support for Big Sur.
