Inaccurate partial changes in tunings can create problems.

Some computerized tuning systems contain as many as 4, 5, or even 6 partial changes, and errors at each partial change are common and often large enough to cause audible ‘hiccups’ in the tuning.

If the errors are less than 0.3 cents or so, they are insignificant.    But partial change errors of .5 cents or more can easily be heard and create ‘hiccups’ in the tuning.

Any tuning system’s software will work on a long scale piano, but on the shorter scales, the combined effect of scaling issues and partial change errors, can cause issues in the bass and mid range – particularly on small grands, consoles, and spinets.

There’s nothing we as tuners can do to correct the scaling but we should address errors at partial changes.   Only after the partial changes errors have been corrected, can an accurate stretch be determined for the piano.

Transitioning from plain wire to wound strings, and going from long bridge to bass bridge, is a challenge for both designer and tuner.

Scaling issues can be worsened by errors at partial change.

Some software tries to remedy the scaling issues by allowing the technician to enter the locations of the bridge break and the plain wire to wound string break into their software before the tuning is ‘calculated’.   Then the software takes another ‘guess’ at a correction.   Sometimes this may improve their results a little, but it’s still a ‘guess’ as to exactly what is going on at the pianos’ scaling breaks and the software’s partial changes.

Only after the partial changes have been addressed can a real solution be found as to how to best deal with the scaling issues.