跌近 100 cents：Yamaha YU121 點樣翻生？Nearly 100 Cents Flat: Bringing a Yamaha YU121 Back to Life

這部杭州製 Yamaha YU121 來英國接近四年，客人表示來英國後從未調音。 This Hangzhou-made Yamaha YU121 had been in the UK for almost four years. The client said it had not been tuned since arriving. 檢查時發現，A4 已經比 A440 低約 30 cents。中音區本身已經明顯偏低，而高音區更加嚴重，部分高音接近跌了 100 cents (2:25)。這高度提示，這部琴可能已經很久沒有真正回到 A440。 During inspection, A4 was around 30 cents lower than A440. The middle section was already noticeably flat, but the treble was far more serious. Some treble notes were nearly 100 cents flat (2.25). This strongly suggests that the piano may not have truly returned to A440 for a long time. 這種情況已經不是普通 fine tuning。問題不只是幾粒音不準，而是整部琴的 pitch baseline 和張力分布都已經偏離正常範圍。 This was no longer a normal fine-tuning job. The issue was not just a few wrong notes — the whole pitch baseline and tension distribution had moved away from a normal working range. 所以今次的做法，是先用第一轉 pitch raise (1:01)重建整體張力和 pitch structure，然後第二轉才做真正的 final tuning：八度、unisons、穩定度和 tone focus。 So the method this time was to use the first pitch raise to rebuild the overall tension and pitch structure, then use the second pass for the real final tuning: octaves, unisons, stability, and tone focus. 第一轉是救張力。 The first pass restores the tension. 第二轉是救聲音。 The second pass refines the sound. 聲音對比 / Audio comparison: 00:00 — Demo 1 未調音 Before tuning 03:03 — Demo 1 第一轉 pitch raise 後 After first pitch raise 04:11 — Demo 1 Final tuning 後 After final tuning 由昏沉、偏低、冇焦點 到聲音打開 再到和弦更清、更集中 From dull, flat, and unfocused to a more open sound then to a clearer and more focused chord 00:26 — Demo 2 未調音 Before tuning 03:14 — Demo 2 第一轉 pitch raise 後 After first pitch raise 03:38 — Demo 2 Final tuning 後 After final tuning 高音區由明顯偏低、聲音較沉 到比較清楚但仍然有點散 最後變得更穩定，unison 更集中 The treble starts noticeably flat and dull, then becomes clearer but still slightly loose, and finally becomes more stable with more focused unisons. Pitch raise is not just about raising the pitch. It is about restoring the tension balance of the whole piano. 升 pitch 唔只係升音高， 而係重建整部琴的張力分布。 多年冇調的琴，不是不能救。 但要用對方法。 A piano that has not been tuned for years can still be brought back. But it needs the right method.