- Kawai K 18 EOne thing though, a week or so later one of the keys, the 2nd F after Middle C is ......not wrong (and i know it will need tuning) but it seems to shake?! vibrate sort of thing, not because ofk its pitch but just as though the string isnt right>?? i don't know how to explain,. it just feels different! Maybe its nothing and I'm just being over fussy....but if anyone had any helpful info?Thanks. Lau x