ji-trainer

A project to help people train their ears to recognise Just Intonation notes, and provide statistical measures of how good people are at this.

Currently this app is WORK-IN-PROGRESS

Description of what the app should look like

The app should have ability to keep track of user score, and to give the user sequential tests on Just Intonation intervals.

A test should do the following things:

• Have a set of notes (1 = note, 2 = interval, 3+ = chord)
• Ability to press a button and play these notes
  • Will need to consider suitable timbres
  • Sine wave too simple, and no overlapping partials
  • Square is probably too complex
  • Triangle wave might have about the right number of overtones
  • Also look at FM timbres. Although there are not many sidebands - but can truncate FM to create more sidebands. See web-synth project.
  • For 2+ notes, want to play it twice, first time slowly, second time faster (C--E--G--C--------C-E-G-C)
  • For 1 note, want to precede test with notes at a few random frequencies, to make it a good test of absolute perception, and not just memory of previous note played!
  • 1 note is test of absolute perception, 2+ notes is test of identifying intervals. These are different types of test!
• A small (3 to 10 option) multiple choice quiz to correctly identify the note, interval or chord
  • For 2+ notes, the bottom note should be given (RCN or Hz), and only the higher notes need to be correctly identified.
• Answers can have any (or all) of the following forms:
  • Absolute values in Hz (400 Hz, 500 Hz, 650 Hz - fix bottom Hz value)
  • RCN note names (C4, E'4, G#''4 - fix bottom RCN name)
  • Whole-number ratios e.g. 17:19 or 5:7:9:13

A score should

• Be a better score for smaller intervals
• Might be related to the minimum number of cents difference a user can reliably distinguish
• You might have multiple scores issued, e.g. one for seconds (approx 200 cents), another for sixths (750 to 950 cent difference), etc.

Some other ideas:

• Lowest note should be randomised, between say C2 and C7

• Might want to keep score separately in ranges C2, G3, C5, C7. Lower frequencies make it harder to distinguish intervals. Higher frequencies miss the overtones.

• Start off with easier tests (wider intervals, greater distance between chord options) and make tests harder until user fails to get any answers right. (Perhaps have 5 'lives', and end game when 5 mistakes are made.)

• Probably don't want to test more than 5 to 8 notes as once - what's the limit?

• If there are 4 options, then there is 25% chance of getting answer right by chance. Before giving someone a particular score, they ought to repeat it 5 times to show its not a fluke

• Analysis of person's results is likely to be highly statistical!

• Might want to upload high scores from each person to somewhere central (Firebase database?) - so only upload reliable statistics that prove what a person knows.