#76
|
|||
|
|||
Once you settle on a tuner that you feel is super excellent in precision and accuracy, take a stroll down the fretboard and see what you think. Even going from the nut to the first fret will show a great deal of tuning differences on most guitars. Take one of your best songs that you recorded and play it back with digital looping so the tuner has time to lock onto the tone. You may be surprised at how far sharp and flat your best of notes are even with "perfect" tuning at the nut. Some of this is inherent in the fret spacing but much has to do with technique itself too.
Frank Sanns |
#77
|
||||
|
||||
Quote:
Precision and accuracy, as we are discussing them are not a trade-off. They are independent. A wide scatter or a narrow scatter can both average to either a "true score" or to an error. However, if the focus is on the achievement of an accurate prediction, they are dependent, with precision setting a limit on the likelihood of "success". In the context of reliability/validity, the validity coefficient can't exceed the square root of the reliability coefficient. This has to do with the theoretical relationship of observed scores to true scores. WARNING -- UNLESS YOU"RE REALLY INTO THIS DISCUSSION, YOU MIGHT WANT TO SKIP THIS NEXT PARAGRAPH: Reliability, in techno-speak, is the proportion of variance in a set of observations that arises from the state of the entity being measured (e.g., the proportion of variance in observed temperature values that arises from actual differences in temperature and not other factors, such as quirks of the measurement tool). If the proportion of variance between an indicator and a true score is .64, the correlation between the true score and the indicator is the square root of .64, or .80. If validity is established by means of camparing the indicator being evaluated to another indicator of perfect reliability (the best case), the latter would have a correlation with the true score of 1.0. Thus, the maximum correlation possible between the measurement and the infallible indicator is the product of the two indicators' correlations with the true score, or 1.0 x .80 = .80, the square root of the reliability. So, the greater the reliability, the higher the possible validity. Note that, in this context, validity is defined in terms of correlation -- the ability to predict the true score. It doesn't imply that the measurement obtained is the same as the true score (think of predicting Fahrenheit temperature from a Celsius thermometer -- excellent prediction even though the numbers are different). The discrepancy between the estimate and the true score is not measurement error but miscalibration. The predictive power isn't compromised by miscalibration but without correcting the miscalibration, the estimate will be off the mark (in completely predictable, nonrandom, ways).
__________________
Bob DeVellis |
#78
|
|||
|
|||
I smell a discussion about Gauge R&R right around the corner...
__________________
侘 寂 -- wabi-sabi -- acceptance of transience and imperfection by finding beauty in that which is imperfect, impermanent, and incomplete |
#79
|
|||
|
|||
Quote:
A precise tuner, will give up the same flat or sharp notes within x +/- cents. If it wasn't precise, one time you strike the b string, its output ends up being 5 cents of, the time time, maybe it's 12 cents off. etc. Precise readings will give you a result that is consistent (always withing +/- x cents), if not correct.
__________________
Correlation does not imply causation. |
#80
|
|||
|
|||
Quote:
Frank Sanns Last edited by FrankS; 01-17-2014 at 10:32 PM. |
#81
|
||||
|
||||
Before this goes from the sublime to the ridiculous (possibly it's too late? ), maybe we should try to get this back to the intent of the OP?
Agreed...ideally a tuner should be both accurate & precise. However, what one uses, or how one goes about determining that, is subject to error as well. To ensure accuracy, one would need to calibrate the tuner to some standard that is known to be at near perfection (not likely something most of us have access to). Imprecision, on the other hand, is inherent to each individual device (i.e. tuner), and not generally something that we can improve. Therefore, since true accuracy and precision are for the most part outside of our control and entrusted to the tuner manufacturer, just tune using the method that works best for you, and play, play, play!
__________________
Martin 000-28EC '71 Harmony Buck Owens American Epiphone Inspired by Gibson J-45 Gold Tone PBR-D Paul Beard Signature Model resonator "Lean your body forward slightly to support the guitar against your chest, for the poetry of the music should resound in your heart." -Andrés Segovia |