A register hole kills one resonance while sparing another.

Evidence

The register hole marked in Figure 4.19 is a small hole on the back of the instrument which is controlled by the thumb of the left hand which either covers it completely, half covers it by press­ ing the thumb nail end-on against it, or uncovers it completely. To suppress the first mode in this way without affecting the second, this hole should be drilled in a position where the undesired mode has a pressure maximum. When all the tone holes are covered, this would be exactly halfway down the resonator—a point where the first mode has a pressure maximum and is therefore reduced, but the second mode has a pressure node and is there­ fore unaffected (see Figure 4.18). — David Howard, Jamie Angus, coustics and Psychoacoustics, 1221

Categorization

Category: Definitional Content

• DEFINE: Explains the physics of register-hole venting using pressure antinodes and nodes — foundational for overblowing.

Related

• A register hole suppresses unwanted modes by sitting at their pressure antinode (similarity 0.89)
• Register holes exploit mode geometry to suppress one mode while sparing others. (similarity 0.89)
• Register holes force a jump to a higher mode by removing harmonic support. (similarity 0.88)
• Register holes suppress unwanted modes by exploiting pressure nodes and maxima (similarity 0.87)
• Striking a membrane at a nodal line silences that mode entirely (similarity 0.82)
• Register holes force overblowing by stripping the fundamental of its harmonic support (similarity 0.82)
• A register hole suppresses odd harmonics while leaving even ones intact (similarity 0.81)

Broader Connections

• Tone-hole fingering requires modes to keep constant frequency ratios as holes open #qualifies (0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1211