Piano Quality Control & Assurance 5

Question 1

A regulation inspector uses a 'blow distance' measurement during QC. What is blow distance?

Accepted Answer

The distance from hammer head to string when the key is at rest

Answer

Blow distance (or 'let-off distance') is the gap between the resting hammer and the strings, affecting hammer travel and tone.

Question 2

Which QC step most directly addresses unevenness in tone volume (one note louder than its neighbors at equal key force)?

Accepted Answer

Voicing individual hammers to equalize tonal output

Answer

Voicing by needling or lacquering hammers adjusts their density, which controls how much energy each hammer transfers to the string.

Question 3

An inspector checks 'string bearing' on the treble bridge using a straightedge. What defect is being screened for?

Accepted Answer

Strings lifting off the bridge — indicating insufficient down-bearing that would reduce tone transfer

Answer

If strings lift off the bridge, there is no down-bearing and the soundboard receives little or no vibrational energy from those strings.

Question 4

What does 'pinblock integrity' testing assess in a piano QC process?

Accepted Answer

The ability of the laminated pinblock to hold tuning pins firmly without slipping

Answer

The pinblock must grip tuning pins tightly enough to hold pitch; failed lamination or splits cause pins to slip and the piano to go out of tune rapidly.

Question 5

During a final QC listening test, a technician identifies a 'thump' on certain bass notes that does not come from the string. What should be investigated first?

Accepted Answer

Loose internal components such as screws, felts, or the plate bolts resonating sympathetically

Answer

Low-frequency bass notes vibrate at frequencies that cause loose hardware or components inside the case to resonate and produce extraneous thumps.

Piano Practice Test

Piano Practice Test

Piano Quality Control & Assurance 5