Helmut Wabnig
2011-03-01 08:18:23 UTC
Nylon Guitar Sustain, Loudness and Wolf Tones.
A guitar should have a loud and long lasting tone.
Those two attributes are contraproductive:
Loudness kills sustain.
When more energy is radiated as sound, it will last shorter-
Where those criteria collide, WOLF tones appear.
Loudness depends on the player and cannot be easily normalized,
but sustain can be objectively measured, because it is player
independent. For practical reasons I suggest measuring the
peak loudness of a played tone and measure the time it takes
to decay at 1/4 of the original amplitude. That corresponds
to a -20dB loudness reduction. The time is in the range
of seconds for a nylon guitar.
A complete sustain map, or chart, or diagram, reveals all
acoustically bad spots of an instrument. Especially hidden
or apparent Wolfs can be visualized. The procedure is
straightforward and simple, although somewhat technical,
because good computer skills are required when using
a computer as measurement device.
I consider the sustain map as the ultimate proof of a luthier's.
Combined with the intonation measurement that method
equals a thorough X-ray plus CT plus MRT of a guitar.
Master instrument makers should present their intonation diagram
and their sustain diagram to customers.
No incense magic smoke, no Voodoo, but open honesty.
Watch:
w.
A guitar should have a loud and long lasting tone.
Those two attributes are contraproductive:
Loudness kills sustain.
When more energy is radiated as sound, it will last shorter-
Where those criteria collide, WOLF tones appear.
Loudness depends on the player and cannot be easily normalized,
but sustain can be objectively measured, because it is player
independent. For practical reasons I suggest measuring the
peak loudness of a played tone and measure the time it takes
to decay at 1/4 of the original amplitude. That corresponds
to a -20dB loudness reduction. The time is in the range
of seconds for a nylon guitar.
A complete sustain map, or chart, or diagram, reveals all
acoustically bad spots of an instrument. Especially hidden
or apparent Wolfs can be visualized. The procedure is
straightforward and simple, although somewhat technical,
because good computer skills are required when using
a computer as measurement device.
I consider the sustain map as the ultimate proof of a luthier's.
Combined with the intonation measurement that method
equals a thorough X-ray plus CT plus MRT of a guitar.
Master instrument makers should present their intonation diagram
and their sustain diagram to customers.
No incense magic smoke, no Voodoo, but open honesty.
Watch:
w.