When a piano has not been tuned for a long time, the pitch drops further and further away from where it should be. It becomes harder to pull the strings back up to tune it. Therefore, when the pitch is very low, the piano needs a pitch raise. Technicians have to first raise the tension of the strings to their proper average tension levels, then the piano can be accurately tuned. Otherwise, if we tune the piano and pull the tension of the strings in one big jump, this would put a lot of strain on the piano's structure and the tuning would be unstable. The cost for a pitch raise is 70$ +taxes.
