Regulation on a piano is the equivalent of doing the timing and other adjustments on a car – such things as steering geometry (toe-in angles and correct wheel alignment) and clutch pedal take-up point are most important for your car. If your clutch judders, or the steering or brakes aren’t adjusted properly, your car may become hard or even dangerous to drive.
In the same way, there are correct tolerances for all pianos – such aspects as key-dip (the amount the keys go down) hammer strike (the distance between the hammer and the string) damper lift-off point, set-off (and in roller action grands let-off and repletion spring tension).
Where the regulation is not within the correct tolerances, hammers may bounce or ‘blubber’ (you press the note once but it repeats maybe three times very rapidly), or the note doesn’t work. The keys may feel overly heavy or stodgy, or the touch may be much too light, notes may ring on when they should stop cleanly, or the notes don’t ring on when they should. A good piano when properly regulated and tuned, will feel good to play, sound nice to hear, and respond to the player in a very pleasing and dynamic way.
However, a piano which is in need of regulation, even if well tuned, can be very unsatisfactory to play, and is not working anywhere near its’ full potential.
As with tuning, repairs and restoration, any estimate I give will include any necessary regulation which may be needed. Just to remind you, I give free estimates with a 25-mile radius of Petersfield, and only charge a call-out fee of between £30 and £50 for pianos further away than this. For those interested in going deeper into piano restoration, regulation and tuning, I highly recommend the excellent book ‘Piano Servicing, Tuning and Rebuilding’ by Arthur A Reblitz.