Harmodire

★★★★★ Just what I was looking for! Easily allows you to compare how combinations of notes (chords) in different tuning systems sound with the press of a button. The layout is well thought out, and notes can be played separately or held. Just, equal and meantone tuning are the standard presets, and there are 3 custom options to make your own. I wish Pythagorean had also been included, as it is one of the major ones. I also love that you can change A to something other than 440hz. Tone 3 sounds the best to me, at least on my phone's speakers. Can change octaves, but the octave buttons don't change colour to show that they've been pressed. Potential nice future feature: allow importation of 12-pitch .scala tuning files (or any number of pitches, and change the keyboard depending on their number, though that would certainly be more complicated). In any case, this is a great app to quickly demonstrate to someone what an audible difference different tuning systems can make. E.g. hold down C and G, and change from equal to meantone to just - the different number of beats is very audible. But for such educational use, I highly recommend setting the root position to manual rather than the default automatic (which adjusts to whatever your lowest note happens to be) because this is the way it is in real life when tuning instruments. Just intonation sounds wonderful on any note when you're in automatic, but set the manual root to C and compare how the C-G and D-A intervals sound now! This in turn can then start a conversation about why so many different tuning systems have been developed - musical tuning is broken symmetry. If one thing works really well in a particular tuning system, something else will typically sound terrible.