The structure of a Acoustic guitar

• Fretboard
  • Material: Commonly rosewood, maple, or mahogany (rosewood offers warm tones, while maple produces bright sounds).
  • Frets: Metal strips inlaid on the fretboard, dividing pitch regions (folk guitars typically have 20–22 frets).
  • Position Markers: Dots/squares on the side of the fretboard to help locate positions quickly (e.g., 3rd, 5th, 7th frets).
• Truss Rod
  • Position: A metal rod inside the neck, used to adjust the neck’s curvature (alleviating bending caused by string tension).
  • Adjustment: Via a hex key hole at the headstock or neck heel, ensuring the fretboard remains flat.
• Action
  • Definition: The distance between the strings and fretboard (typically 2.5–3mm at the 12th fret).
  • Impact: Excessive action makes fretting difficult, while too low action causes buzzing (strings vibrating against frets).

3. Body

(1) Soundboard/Top

• Material:
  • Spruce: Common in folk guitars, offering bright tones and balanced resonance—ideal for strumming and fingerpicking.
  • Cedar: Warm and soft tones, often used in high-end fingerstyle guitars.
• Bracing
  • Position: Wooden support structures inside the soundboard (e.g., X-bracing, fan bracing).
  • Function: Enhances soundboard strength and optimizes sound wave reflection. X-bracing is a classic design in folk guitars, balancing tone and durability.
• Sound Hole
  • A circular opening at the center of the soundboard, allowing sound from the resonance chamber to project outward. Some guitars feature decorative inlays (e.g., mother-of-pearl) around the sound hole.

(2) Sides & Back

• Material:
  • Mahogany: Full-bodied tones with prominent mids, suitable for folk styles.
  • Rosewood: Deep lows and smooth highs, often used in premium guitars.
  • Maple: Bright, crisp tones with strong resonance (common in electro-acoustic models).
• Structure:
  • Sides and back form a closed resonance chamber, working with the soundboard to create "cabinet resonance" (similar to a speaker amplifying sound).

(3) Bridge

• Position: Below the soundboard, fixing strings and transmitting vibrations to the soundboard.
• Components:
  • Bridge Pins: Inserted into bridge holes to secure string tails.
  • Saddle: A raised part on the bridge, similar to the nut at the headstock, affecting intonation and tone (often made of bone or plastic).

(4) Other Details

• Pickguard
  • Attached to the lower soundboard to prevent pick scratches (folk guitar pickguards are usually plastic or celluloid, with diverse patterns).
• Strap Buttons
  • One at the bottom of the body and one at the neck heel, for attaching a strap (for standing performances).
• Electro-Acoustic Add-Ons
  • Electro-acoustic folk guitars feature a pickup and control panel (to adjust volume and tone), with a jack at the bottom for connecting to an amplifier.

4. Impact of Core Structures on Tone

5. Common Folk Guitar Body Types

• Dreadnought
  • Features: Wide body, powerful volume, and strong lows (e.g., Martin D-28), perfect for singing and rhythmic accompaniment.
• Concert/OM (Orchestra Model)
  • Features: Narrower body, balanced and delicate tone—ideal for fingerpicking and melodic playing (e.g., Taylor GS Mini).
• Jumbo
  • Features: Extra-large body with extreme resonance, suitable for stage performances or scenarios requiring grand tones.