I have seen this situation a couple of times with the same small grand. The piano is an entry level 150cm grand made by a respected manufacturer, that’s five feet long in the old language, and the owners say to me that the treble and high treble is weak in sound.
The quality of this piano is aimed at the recreational pianist more than the professional, but with my experiences the piano was used for intermediate to advanced grades.
Before I start tuning a piano, I always ask the customer the use of the piano, so I know the type of music the musician plays as well as the requirements of the pianist, for example lots of soft playing or a more “bash out a song” technique. In both these instances, the piano was in great condition and the regulation of the mechanism was quite good. A simple chromatic scale from 1 to 88 to gauge the level of sound proved the bass had a good level of sound, the cross over from copper wound to steel strings was good however the mid section produced a lot of volume and then progressively seemed to get softer in the high treble. A few arpeggios proved the test: good bass, loud middle and the high treble just didn’t sing enough. The customer was right. The treble was weak. Was that the answer?
I have already given the answer away. Don’t just look at the problem, look at the surrounding environment as well as the entire instrument. Sometimes the answer comes from looking at the tiled floor, or the small echo in the room’s acoustic. In this case, the room was fine and the piano itself played well, however working on the high treble wasn’t the answer. The overall sound balance wasn’t right. The mid section was too loud.
I worked on the hammers of the mid section. The hammers themselves were hard and not very resilient, however to work on this would take around four hours to correctly work on the hammers. This would produce a better quality sound however being about the third technician to work on this instrument, the owners were a little unsure with my diagnosis. To the customer it seemed strange that I was advising to work in the middle to improve the high treble. I needled the hammers on the top of the hammer and around the string marks so the “attack” of the hammer striking the string was a little softer. This is performed with a short fine needle pushed towards the centre of the hammer, but not used in a way of “digging for potatoes”. This took around 20 minutes to complete.
The results proved my theory of the middle section being too loud. Playing a chromatic scale resulted an even tone gradually becoming brighter towards the high treble. Arpeggios were balanced with the top notes having that required “lift” on the top notes. I asked the pianist to try the piano and she played Debussy and Ravel and the top notes sung.
Somehow, I “brightened up the treble”.