Tenney–Euclidean tuning: Difference between revisions

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'''Tenney-Euclidean tuning''' ('''TE tuning'''), also known as '''TOP-RMS tuning''', is a tuning technique for regular temperaments which leads to the least sum of squared errors of the TE-weighted basis.  
'''Tenney-Euclidean tuning''' ('''TE tuning'''), also known as '''TOP-RMS tuning''', is a tuning technique for regular temperaments which leads to the least sum of squared errors of the Tenney-weighted basis.
 
If we have ''k'' linearly independent [[Vals and tuning space|vals]] of dimension ''n'', they will span a subspace of [[Vals and tuning space|tuning space]]. This subspace defines a regular temperament of rank ''k'' in the prime limit ''p'', where ''p'' is the ''n''-th prime. Similarly, starting from ''n'' - ''k'' independent commas for the same regular temperament, the corresponding monzos span an ''n'' - ''k'' dimensional subspace of [[Monzos and interval space|interval space]]. Both the subspace of tuning space and the subspace of interval space characterize the temperament completely. A question then arises as to how to choose a specific tuning for this temperament, which is the same as asking how to choose a point (vector) in this subspace of tuning space which provides a good tuning. One answer to this is the weighted RMS ([[Wikipedia: Root mean square|root mean squared]]) tuning discussed right here.


TE tuning can be viewed as a variant of [[TOP tuning]] since it employs the [[Tenney-Euclidean metrics #TE norm|TE norm]] in place of the [[Tenney height]] as in TOP tuning. Just as TOP tuning minimizes the maximum Tenney-weighted ''L''<sub>1</sub> error of any interval, TE tuning minimizes the maximum Tenney-weighted ''L''<sub>2</sub> error of any interval.
TE tuning can be viewed as a variant of [[TOP tuning]] since it employs the [[Tenney-Euclidean metrics #TE norm|TE norm]] in place of the [[Tenney height]] as in TOP tuning. Just as TOP tuning minimizes the maximum Tenney-weighted ''L''<sub>1</sub> error of any interval, TE tuning minimizes the maximum Tenney-weighted ''L''<sub>2</sub> error of any interval.


== Introduction ==
== Definition ==
If we have ''k'' linearly independent [[Vals and tuning space|vals]] of dimension ''n'', they will span a subspace of [[Vals and tuning space|tuning space]]. This subspace defines a regular temperament of rank ''k'' in the prime limit ''p'', where ''p'' is the ''n''-th prime. Similarly, starting from ''n'' - ''k'' independent commas for the same regular temperament, the corresponding monzos span an ''n'' - ''k'' dimensional subspace of [[Monzos and interval space|interval space]]. Both the subspace of tuning space and the subspace of interval space characterize the temperament completely.
 
A question then arises as to how to choose a specific tuning for this temperament, which is the same as asking how to choose a point (vector) in this subspace of tuning space which provides a good tuning. One answer to this is the weighted RMS ([[Wikipedia: Root mean square|root mean squared]]) tuning.
 
== TE tuning ==
If we put the weighted Euclidean metric on tuning space, leading to TE tuning space in weighted coordinates, it is easy to find the nearest point in the subspace to the [[JIP]] {{val| 1 1 … 1 }}, and this closest point will define a [[tuning map]] which is called TE tuning, a tuning which has been extensively studied by [[Graham Breed]]. We may also keep unweighted coordinates and use the TE norm on tuning space; in these coordinates the JI point is {{val| 1 log<sub>2</sub>3 … log<sub>2</sub>''p'' }}. The two approaches are equivalent.  
If we put the weighted Euclidean metric on tuning space, leading to TE tuning space in weighted coordinates, it is easy to find the nearest point in the subspace to the [[JIP]] {{val| 1 1 … 1 }}, and this closest point will define a [[tuning map]] which is called TE tuning, a tuning which has been extensively studied by [[Graham Breed]]. We may also keep unweighted coordinates and use the TE norm on tuning space; in these coordinates the JI point is {{val| 1 log<sub>2</sub>3 … log<sub>2</sub>''p'' }}. The two approaches are equivalent.