Woods for the flamenco guitar back and sides
While the top gives the flamenco guitar its responsiveness and sustain, the back and sides act as a resonator effecting the harmonic mix and overall tone of a flamenco guitar significantly. Two types of rosewood are commonly used in flamenco negra guitars: Brazilian rosewood and Indian rosewood. Both rosewoods have an extremely high velocity of sound and a broad range of overtones. Rosewoods are denser giving the guitar more sustain, more depth of tone, sounding slightly mellower and richer. They have strongly pronounced low overtones giving the flamenco guitar an overall darkness of tone. The design of the flamenco guitar enables strong mids and highs to strengthen the overtones generated by the top, contributing to a very enchanting fatness of tone on the upper registers. Brazilian Rosewood has highly figured, often multi colored, beautiful grains, but is more difficult to work with Brazilian rosewood than with Indian rosewood. Indian rosewood has more straight grains. Brazilian rosewood has become increasingly expensive and rare. Brazilian rosewood is protected since 1992. Its cut is severely sanctioned and export is restricted to tree cuts from before 1992. For this reason, a flamenco negra guitar made of Brazilian rosewood is commonly bought with a conformity certificate in order to protect South American forests. The availability of Indian rosewood is no problem since it is cultivated on plantations. Indian rosewood has the tendency to absorb humidity only slightly and therefore is more stable than Brazilian rosewood. Indian rosewood has a warm, rich, responsive tone with clear bass projection without overpowering the midrange or trebles tones. Since Brazilian rosewood is difficult to obtain, other alternative woods, similar to those of Brazilian rosewood, are used for the back and sides of flamenco guitar, such as Madagascar rosewood, Honduran rosewood, Cocobolo, kingwood, Caviuna, Palo Escrito or Pau Ferro. Pau Ferro has a fast, clean response that represents the entire spectrum of the tonal register. Palo escrito has a lower density, compared to Brazilian or Indian palosanto, and reflects a nice percussive negra sound with a very low sustain that we flamenco guitarists love. Madagascar is evenly responsive across the entire tonal register projecting a crisp sound with average sustain similar to old-growth Brazilian Rosewood. While Brazilian Rosewood will make a great sounding flamenco guitar, however with quite significant sustain, there are alternative woods available that will make an equally nice looking ans sounding flamenco guitar but for considerably less money. Indian Rosewood will ensure an absolutely amazing guitar and Madagascar Rosewood, Cocobolo, Palo Escrito or Pauferro are all suitable alternatives. All these woods will produce many of the same looks and sounds like that of Brazilian rosewood.
When comparing tonewood, there are 3 important parameters to consider: hardness, density, and elasticity. Hardness and density influence sustain, the harder and more dense, the longer the sustain will last, the longer a "rings forever" kind of sound. Elasticity influences the power and punch to the voice of a guitar, it influences the elastic motion of the back and sides in response to the motion of the soundboard top, the higher the elasticity, the more power and punch.
- Hardness: Indian rosewood and Palo Escrito have a low hardness, Brazilian and Honduran rosewood have an average hardness, Cocobolo and Blackwood have the highest hardness
- Density: Indian rosewood and Palo Escrito are less dense, Brazilian and Honduran rosewood have an average density, Cocobolo and Blackwood are very dense
- Elasticity: Blackwood and Cocobolo are inelastic (rigid), Brazilian, Honduran and Indian rosewood are moderately elastic, Palo Escrito is very elastic
Three types of cypress are commonly used for the sides and back of flamenco blanca guitars: Cypress royal, cypress coral and cypress violetta. Cypress is light and because of its stability, cypress can be worked very thin, projecting a percussive, bright and clear, crispy sound with plenty of flamenco "bite" in the trebles. Since cypress was abundant and cheap in Spain, at the end of the 19th century, most the flamenco guitars of the legendary Spanish guitar maker Antonio Torres (1817–1892), were cheap cypress flamenco guitars that Gypsies could to afford to play flamenco. Nowadays, premium grade cypress is very hard to find and becoming increasingly more expensive. Cypress coral is harder than cypress royal, producing a very bright tone. Juan Montero Aguilera and Pedro de Miguel have cypress coral to make very fine flamenco guitars. The very rare cypress Violetta is also harder than cypress royal, but is produces a much more wooden, somehow more sweet tone. Juan Miguel Gonzalez is one the very few flamenco guitar makers being able to use this very rare, enchanting cypress Violetta on his flamenco guitars.
Maple is a more acoustically transparent wood compared to the rosewoods. Since maple has a low velocity of sound it only slightly affects the tonal characteristics of the flamenco guitar top. Sides and back of maple, tend to alleviate some of the overtones emanating from the guitar top. Like cypress, maple sides and backs can be made very thin, yet produces a somewhat fuller sound than cypress without being as mellow as rosewood.
Some flamenco guitar makers like Andres Dominguez combine cypress royal with rosewood making a outstanding flamenco guitars with a very specific flamenco sound, percussive and more depth of tone, but still very bright. Andres Dominguez his Quique Parides model is one of his flamenco guitars with back and sides made from cypress royal and rosewood.