Guitar Bridge Admittance

Consider the limiting case of a lossless bridge
(zero damping, mass-spring model only):

• Bridge = pure reactance (no sound gets out)
• String-body coupling is energy conserving
• All poles on $j\omega$ axis (infinite-Q resonances)
• All zeros on $j\omega$ axis (infinitely deep notches, or anti-resonances at various frequencies)
• Resonances and anti-resonances alternate
• Impedance looks like a spring at DC ($\omega=0$)
  (``stiffness controlled'')
• Impedance looks like a mass at $\omega=\infty$
  (``mass controlled'')
• As frequency increases, driving-point impedance alternates between looking like a mass and looking like a spring, changing as each resonance or anti-resonance is passed.
• Looks like a spring at frequencies above an anti-resonance and below a resonance
• Looks like a mass at frequencies above a resonance and below an anti-resonance