Acústica para guitarreros

• Vibraciones y ondas
• Ecuaciones de onda
• Vibración de cuerdas
• Vibración de placas. Patrones de Chladni
• Caja de resonancia
• Radiación
• Compensación
• Sintonía tapa-fondo
• Efecto del puente
• Influencia de los materiales
• Acústica de salas
• Amplificación electrónica de la guitarra acústica

1.2: Simple harmonic motion

• 1.2.1: Mathematical definition of simple harmonic motion
• 1.2.2: Geometrical model of simple harmonic motion
• 1.2.3: The period of simple harmonic motion
• 1.2.4: An example of simple harmonic motion
• 1.2.5: The energy embodied in simple harmonic motion

1.3: Introduction to the mechanics of beams

• 1.3.1: Stiffness of simple beams
• 1.3.2: The mass of a simple beam
• 1.3.3: Vibrating systems

1.4: Resonance and vibration sensitivity

• 1.4.1: Simple resonators
• 1.4.2: The Helmholtz resonator
• 1.4.3: Damped simple resonators
• 1.4.4: Driven, damped simple resonators – strings driving soundboards
• 1.4.5: The detailed behaviour of a simple driven resonator
• 1.4.6: The Q-Factor
• 1.4.7: Mechanical Impedance
• 1.4.8: Impedance (mis)matching
• 1.4.9: Impedance, admittance and the high performance guitar
• 1.4.10: Beats

1.5: Vibrations in strings and the forces they exert

• 1.5.1: Types of waves in strings – frame of reference
• 1.5.2: Transverse waves in strings
• 1.5.3: Wave partials and harmonicity
• 1.5.4: Waves in “ideal” strings
• 1.5.5: Forces on the terminations of an ideal string
• 1.5.6: Real strings
• 1.5.7: Plucking at places other than the centre
• 1.5.8: Forces exerted by a string on a soundboard
• 1.5.9: Strings with bending stiffness

1.6: Vibrations of bars and plates – strings driving soundboards

• 1.6.1: Vibrations of bars
• 1.6.2: Vibrations of plates with free edges
• 1.6.3: Vibrations of flat plates fixed around their edges
• 1.6.4: Guitar vibration modes excited by the string forces
• 1.6.5: Vibrations of curved plates (spherical shells)

1.7: Sound radiation from a guitar

• 1.7.1: How sound is radiated by a guitar
• 1.7.2: Monopole sound radiation and specific mobility
• 1.7.3: Monopole mobility and the frequency response curve
• 1.7.4: The anatomy of a plucked note
• 1.7.5: Sound radiation from the guitar cavity at middle frequencies
• 1.7.6: Sound radiation and directivity

2: Analytical Guitar Models and their Use

2.1: Coupled resonators and simple low frequency guitar models

2.2: Coupled resonators

• 2.2.1: Two mass coupled resonator

2.3: Two degree of freedom model of a guitar’s low frequency response

• 2.3.1: Low frequency response of a guitar with a stiff back
• 2.3.2: Two mass coupled resonator model for guitars
• 2.3.3: Using the Two degree of freedom model to determine fh
• 2.3.4: Direct determination of the Helmholtz frequency
• 2.3.5: Use of the Two degree of freedom model in the workshop
• 2.3.6: Using the Two degree of freedom model for guitars with live backs
• 2.3.7: Some unusual features of guitar shaped cavities
• 2.3.8: “Live back” guitar low frequency response
• 2.3.9: Coupled top plate and back plate guitar model
• 2.3.10: Target values for the main top and main air resonances
• 2.3.11: Investigative modelling – working in the frequency domain
• 2.3.12: Empirical adjustment of plate frequencies
  • 2.3.12.1: Top response to small perturbations in mass
  • 2.3.12.2: Guitar response to side mass

2.4: Simulation of a guitar’s frequency response

• 2.4.1: A Four degree of freedom model of low frequency guitar function
  • 2.4.1.1: Four degree of freedom model sensitivity analysis
  • 2.4.1.2: Four degree of freedom model and “live” backs
• 2.4.2: The behaviour of superimposed simple sound sources
• 2.4.3: Combining the Four degree of freedom model with superimposed simple sources

2.5: Coupling of strings to soundboards

Annexes

Annex I

• AI 1: Technical note on collecting spectrographic data
• AI 2: Using Chladni’s technique to visualise vibration modes

Annex II

• AII 1: Deflection of the soundboard under oscillating longitudinal string forces
• AII 2: Four Degree of Freedom model of low frequency guitar function
• AII 3: Fretboard Curvature

Annex III

• AIII 1: Frequency look-up table

Annex IV

• AIV 1: Bending waves on plates