Test conditions

Tests were conducted over a period of days, starting with preliminary tests to confirm the operation of the equipment and to get some idea of the string behaviour. Initial data and photos are located at the end of this document. The following test conditions were established and then adhered to:

1. Vibration sensors adjusted to just touch strings at 0 scale mark with LED indicators, such that striking the other string would cause LED activity.
This is done routinely.
2. Strings and contacts sprayed lightly with contact cleaning spray at routine intervals.
3. Vibration sensor frame clamped to string test rig and positioned at mid point of string (65mm)
4. Hammer positioned to strike string at marked point
5. Other string damped to prevent any vibration
6. Key striker clamped to bench to prevent upwards movement
7. Positions of test rig, hammer and striker marked on bench to allow same
position to be resumed

Test data
• Test 1 – To determine the maximum vertical vibration distance of both strings at various MIDI velocities.

Analysis

• Maximum vertical deflection of the Stuart string = 2.2 mm
• Maximum vertical deflection of the Steinway string = 1.8 mm
• The Stuart string shows a higher vertical deflection than the Steinway string at all tested velocities
• At velocity 81, the Stuart string exhibits a 22% higher vertical deflection than the Steinway string.

Conclusion

• Compared to the Steinway string, the Stuart string exhibits a higher deflection in the vertical direction when struck by a hammer also travelling in the vertical direction