Richard Brenkne suggests: >I personally am convinced that if ETD would provide us information >about more then one partial at a time (as in 3 or 4) we could learn >an awfull lot about this process. Here's the difficulty, Richard. For an ETD to display tuning information about several partials, that ETD would need to have a target frequency for each of those partials. Where should we get that target from? Current ETDs all use a tuning curve to specify the target frequencies. The tuning curve specifies the cents offset from a zero-stretch equal-tempered scale. The tuning curve also specifies which partial to use for each note. So we only have a target specified for one partial for each note. If we were to display tuning error for several partials we would need to have an enhanced tuning curve that specified the stretch for each partial. How would we go about generating such a curve? We could use models of inharmonicity like the SAT (FAC method). But if any manual tinkering is required, can you imaging the complexity of the editing screen? Instead of just one curve, there would be 3 or 4 curves. Would you edit them separately, or would one editing operation move all curves simultaneously? How would you make allowances for measured inharmonicity? Once you figure out how to generate a multi-partial tuning curve, then in principle it would not be hard for the RCT or TuneLab to have several spinners or phase displays (although, I would probably have to stop supporting 486's). The desire to see several partials at once may have research appeal, but I doubt it would be of much day-to-day use. If you don't mind using the same stretch numbers, you can quickly change the partial in TuneLab using the F3 and F4 function keys to take a peek. The only context in which this multiple partial thing came up is in regard to unisons. And even the most ardent ETD fan will probably still tune unisons by ear (except possibly for the high treble where multi-partials are not an issue). If you really want to play around with multi-partial, do as Steve Fairchild has suggested and get several ETDs together, each set for a different partial. -Robert Scott Real-Time Specialties
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