Tonewoods for a Guitar’s Soundboard

Tonewoods for a Guitar’s Soundboard

At Intune Instruments we pay careful attention to the selection of tonewoods used on our custom-made sting steel and classical instruments.

One of the commonly asked questions by customers are regarding the choice of tonewoods used and their tonal properties it will have on their guitar. Whilst tonewoods do play an important factor, the luthier’s skills in making a good responsive instrument plays a vital role in bringing out the best tonal and dynamic characters of tonewoods when paired together to build a guitar.

The tonal qualities of the wood are also influenced based on the type of wood species, age of the wood, type of cut whether quarter or flat sawn, drying conditions and the amount of time the guitar is played. The more the guitar is played the more the guitar tone will improve over time. For example, most Spruce top guitars will need time to break-in in order to enhance their best tonal properties. Even guitars built identical to each other by the same luthier with selections of woods from the same trees will have what I call its own personality that will develop over time when played. It takes some hearing skills to notice this but a trained musician will notice this easily. This is what makes it so interesting and brings out the uniqueness with each guitar.

Don’t expect that a guitar not played and stored for years will suddenly begin to sound good after a couple of years. When the guitar is played the vibrations and frequencies cause by strings tension fluctuations cause the sapwood and cell molecular structure to align when played and the guitar finds its sense of equilibrium. This causes a rich tone to develop when a choice of fine tonewoods are used.

Common Guitar Top Woods/ Soundboard materials

 Sitka Spruce (Picea sitchensis)

This a popular choice of tonewood and suited for many playing styles. It pairs very well with all rosewoods and found mainly on steel-stringed instruments. It has a high stiffness-to-weight ratio and makes excellent tops.  It also produces a broad dynamic range and if you’re a player that likes to dig in with an aggressive attack on the strings, this tonewood could handle this with less distortion on the top and bottom end registers. Sitka Spruce’s colouring ranges from creamy white to pale pink and sometime may also feature ‘bearclaw’ figuring that is nowadays getting more popular and preferred by luthiers. Even though a softwood it is more durable than Cedar. Given high stiffness it may need a while to open up. Over time during the aging process the wood darken to a shade of yellowish this adds to the character of the guitar.

The wood is North America and the trees grow tall ranging between 130-160 feet before being harvested, the truck diameter range between 3.5-6 ft, has a hardness of 2,270 N on the Janka scale, Elastic Modulus of 11.03 GPa and a Specific Gravity of 0.36 to 0.42 at 12% moisture content.

Engelmann Spruce (Picea engelmannii)

It also known as Columbia, white spruce, mountain spruce or silver spruce. Mainly found in Western North America in the southern part of Central British Columbia. Engelmann is lighter in weight as compared with Sitka spruce and is preferred mainly by Classical players but also use on Steel Sting guitars.

It tends to have a mature tone of aged instrument and will need less time to open up. The overtones produced are more pronounced and are richer in harmonic content compared to Sitka, but lack has weaker fundamentals. It has warmer tone and a bit more midrange that Sitka and takes a shorter time frame to break in. It also works well for finger style players as it produces complexity in tone colour. Ideal for slight stumming, however it may not handle an aggressive attack to the stings as it tends to have lesser headroom than Sitka. It also pairs well with all rosewoods and goes well with Mahogany, Cocobolo and Ziricote.

It color ranges from white to pale yellow and can be a bit more expensive than Sitka. Typically, the trees can grow up to 130 ft tall, but nowadays it hard to find trees at this size and it getting more limited. It has 1,740 N on the Janka scale, elastic modulus of 31.5 MPa and a specific gravity of 0.33 -0.39 at 12% moisture content.

European spruce (Picea abies and Picea excelsa)

This is found across different parts of Europe mainly in Italy, Switzerland, German, France and in some Eastern European countries. This has remarkable tonal properties and referred to be the best available among the spruce varieties. As it found at higher altitudes it is also noted to be a slow-growing wood. It offers a reasonably good amount of headroom and quicker in response compared to Sitka. The colouring ranges from cream white to a hint of yellowish hint and can be exhibit uniformity in colouring

Picea abies has a 1,680 N hardness on the Janka scale, elastic modulus of 9.70

GPa and a specific gravity of 0.32 – 0.41 at 12% moisture content.

Amongst to most demanded of all European spruce varieties by players looking for the best is the Alpine or sometimes referred to as Moon Spruce. The best trees are found at elevations of over 1000 meters. This is rare to find and can be an expensive choice. The trees are harvested during a particular time during the lunar cycle to where the sapwood is at it lowest point to minimise the wood resins. It’s believed that when the wood is harvested during that time is most stable and durable that allows the top wood to be thinner thereby helping the lighten the weight of the guitar top leading to more resonance in sound. As the sapwood is at its lowest the wood is more stable and to humidity changes.

Sometimes instruments made of moon spruce may sound a tad bit on the brighter side, but that said, it still a magnificent choice of top wood.

Adirondack Spruce (Picea rubens)

The Red Spruce (Picea rubens) is a medium-sized evergreen conifer that grows in cool, boreal forests of the northeast, including the Adirondack Mountains. Adirondack Spruce was the main type of wood that pretty much defined the guitars of that era. With so many trees having been cut down to make guitars and other products, only recently has Adirondack Spruce made a comeback as a new generation of trees have matured. Adirondack Spruce tend to be wide-grained unlike types of Spruce.  They are know to have a good a tonal quality. Soundboards from this specie are able to offer a higher ceiling for volume and can be played loudly without losing clarity. This type of Spruce is getting more popular amongst custom builders of guitars.

Cedar (Thuja plicata)

Western Red Cedar (Thuja plicata) is the most popular choice of tonewoods for classical guitars and also used on selected steel-stringed guitars for players looking for a warmer and sweeter sound.  It’s known for its openness, fullness, mature or aged sound, and has rich harmonics, overtones and a crispness. The tone of Cedar generally is quite open on new guitars but also tends to open up at a faster pace than Spruce, that said, Spruce will continue to open and mature over a span of many years of playing rather than Cedar that will stop at some point.

It’s colouration is darker than Spruce in various shades of light to moderately dark brown, it’s also softer than Spruce and not as durable. Luthiers building steel stringed guitars pay careful attention to the thickness and bracing of the tops so that the guitar can withstand the tension on a steel string instruments., this is not much of problem for classical guitars. It also has weaker fundamentals and a lesser degree of note separation than Spruce.

Whilst Western Red is more commonly used and readily available, there are also other varieties such as Alaskan Yellow Cedar, Port Orford Cedar, Spanish Cedar (used mostly on classical guitar necks)

It’s believed that Cedar started becoming popular as a choice of tonewood around to mid-1960

Western Red Cedar is found in Canada and the Pacific Northwestern United States. The trees grow tall between 165 to 200 ft, it has a hardness of 51.7 MPa and specific gravity of 0.31 – 0.37 at 12% moisture content.

Contact Leroy at Intune Instruments Guitar Repairs and Restoration, Dubai, UAE for Guitar Repairs on +971 50 3950482 or email us at info@intuneinstruments.com