I started this in another thread, but figured it would end up long enough that it could get its own. This will be long...
I also preface this by saying that, as a fingerstyle guy, my preference is small, light, flexible tops. If you strum or play hard, your preference will be exactly the opposite.
Part I - Body Woods:
Sitka Spruce - standard modern wood. Good balance between stiffness and weight to provide both good response and volume. This is a "middle-of-the-road" sound, between compressed/responsive and loud/powerful.
Engleman Spruce - Lighter in color and weight than Sitka. Some volume and top-end is sacrificed to get a richer sound at lower dynamic levels. A good choice for fingerstyle, but tends to lose clarity when played hard.
Adirondack Spruce - standard in the 30s, but scarce since WWII. Stiffer than Sitka and is capable of much more volume, but feels less responsive and likes to be driven hard. Mostly used on bluegrass guitars.
Cedar - Lots of volume and high-end is sacrificed in order to get a rich, warm, pleasant sound when fingerpicking. But, even a strong fingerpicker can push this wood past its optimal level. Tends to lose clarity quickly when played louder. Often used on lower-end guitars to compensate for the thinness caused by poorer quality backs and sides. Used on classicals because it is most similar to traditional white European spruce, which is now scarce.
Mahogany - midrangey and helps a lot with projection. Tends to make a focused, warm, pleasant sound.
Rosewood - allows more volume than mahogany and has a wider frequency response. Tends to sound fuller and richer, but doesn't project as well.
Maple - focuses the tone more on the fundamental. So you sacrifice some richness, but gain more projection and clarity. Brighter and more direct sounding.
Finally, companies cannot be as discriminating with rarer woods (Engleman, Adirondack, and Rosewood especially). They may even be worse quality, and produce a worse sound, than the cheaper Sitka or mahogany. A good rule is to use your eyes. Woods with consistent color, grain, and reflectivity usually are better quality and sound better. Nothing is guaranteed, though. A good piece of wood can be made crummy if mishandled and a crummy piece of wood can be made great. If the company makes a big deal out of using a premium wood, remember that they probably just took what they could get!
The darker grain lines are stiffer than the light ones (slow winter growth vs fast summer growth). A guitar with narrow grain will be stiffer than one with wide grain, all things equal. Stiffer tops sound brighter and have less compression, while more flexible ones sound fuller and respond better to a light touch.
In spruce there is also something called "shimmer" or "bearclaw." It's a variance in the reflectivity of the grain, but not usually the color as is the case with low quality wood. Shimmer or bearclaw is a sign of a stiffer piece of wood.
Everything about Acoustics
Moderated By: mods
Part II: Body Shapes:
In general, the squarer and larger a guitar is, the more volume and bass it can produce. But, a bigger top weighs more and requires more energy to vibrate. So for fingerstyle a smaller top is usually better. In all-things-being-equal land:
Dreadnaughts are the loudest and bassiest. A well-made Adirondack and Rosewood dread can put out over 90db (as loud as a diesel truck). They are the standard for bluegrass because they can get close to the 110db (as loud as a chainsaw) of a well-made banjo.
Jumbos are bigger than dreads, but the extra bend at the waist makes the top functionally smaller. The sound is not as loud, but has better projection in the treble and upper midrange. It a large band situation, you would PROBABLY be able to hear a jumbo better than a dreadnaught. The top is the heaviest of the standard shapes and requires the most energy to move.
A Grand Auditorium is almost the same size as a dread, but an extra little bend at the waist cuts some of the bass.
Grand Concert is smaller and a little more pinched at the waist than a Auditorium. Less bass, and more compression results in less treble response. This is the size most fingerstyle players gravitate towards.
Parlors can come in all shapes and scale lengths, but the same basic rules apply. More shapely shapes mean less bass, and visa-versa. With the smallest, lightest tops of the standard shapes, a parlor SHOULD feel the most responsive to dynamics, but will quickly stop getting louder if played harder.
A longer scale length affects the tone the same way it would on an electric, but also puts more tension on the top. A top under greater tension will have a higher natural resonance and be brighter. Think about it like a drum head. Martin's standard is 24.9", Gibson's 24.75", and others 25.5".
Finally, an acoustic guitar is technically not an "amplified" instrument. The inertia of the moving string is transferred to the top. A bigger top needs more energy to move (either through heavier strings or more plucking force), but can also move more air.
In general, the squarer and larger a guitar is, the more volume and bass it can produce. But, a bigger top weighs more and requires more energy to vibrate. So for fingerstyle a smaller top is usually better. In all-things-being-equal land:
Dreadnaughts are the loudest and bassiest. A well-made Adirondack and Rosewood dread can put out over 90db (as loud as a diesel truck). They are the standard for bluegrass because they can get close to the 110db (as loud as a chainsaw) of a well-made banjo.
Jumbos are bigger than dreads, but the extra bend at the waist makes the top functionally smaller. The sound is not as loud, but has better projection in the treble and upper midrange. It a large band situation, you would PROBABLY be able to hear a jumbo better than a dreadnaught. The top is the heaviest of the standard shapes and requires the most energy to move.
A Grand Auditorium is almost the same size as a dread, but an extra little bend at the waist cuts some of the bass.
Grand Concert is smaller and a little more pinched at the waist than a Auditorium. Less bass, and more compression results in less treble response. This is the size most fingerstyle players gravitate towards.
Parlors can come in all shapes and scale lengths, but the same basic rules apply. More shapely shapes mean less bass, and visa-versa. With the smallest, lightest tops of the standard shapes, a parlor SHOULD feel the most responsive to dynamics, but will quickly stop getting louder if played harder.
A longer scale length affects the tone the same way it would on an electric, but also puts more tension on the top. A top under greater tension will have a higher natural resonance and be brighter. Think about it like a drum head. Martin's standard is 24.9", Gibson's 24.75", and others 25.5".
Finally, an acoustic guitar is technically not an "amplified" instrument. The inertia of the moving string is transferred to the top. A bigger top needs more energy to move (either through heavier strings or more plucking force), but can also move more air.
Part III - Bracing:
The standard brace sizes are 1/4" and 5/16". The smaller braces are more flexible; they allow the top to move more with less force, but that means the top reaches its maximum volume sooner. Smaller bracing is usually better for fingerstyle, and bigger for picking.
Pretty much all you'll find in everything but the highest-end vintage recreations in X-bracing. You can see the "X" through the soundhole. It's the stiffest of the standard bracings, which allows the top to be thinner and lighter. In practice, it gives a great balance of volume and response - the exact reason it's the standard.
"Forward-shifted" X-bracing was the original design used by Martin before 1938. It had one less brace than the current standard, and allowed more flexibility behind the bridge. It was louder and deeper sounding than the current X, but they discontinued it because the strings of the time (14 or 15 gauge in today's terms) warped the tops. It's now used on purpose-made bluegrass dreadnaughts with the caveat "for light or medium strings ONLY!"
Most X-bracing these days is scalloped. Scalloping increases the flexibility of the brace slightly, but mostly is done to lower weight. A guitar with scalloped braces will be louder, deeper, AND more responsive than unscalloped. A better tone in nearly every respect. Some players still choose unscalloped if they prefer a more focused, tight tone and are willing to give up a little volume, or they want a period-correct 1930s-50s guitar.
Ladder bracing was the standard before X-bracing, and dates back to before steel strings (though it was used by some companies through the 60s). Being that it was designed for gut strings, it isn't the best for steel. The sound is a little dark, midrangey, woody, and compressed. Players who choose it usually do so because they want a period-correct guitar for blues or roots music. The sound is less rich than X-bracing, but it does have an appealing "old-timey" quality.
Fan-bracing is used on classical guitars and is designed for the greatest flexibility on instruments that will not have much string tension.
Back braces have less of an effect, and can even be optional. Some Taylor guitars with laminate backs forgo bracing altogether, in favor of a slight arch for strength. Other larger guitars use big, thick braces to keep the wide wood pieces from splitting. I have a guitar from the Depression where the back is braced with glue-soaked cloth! More bracing tightens the tone and increases projection, while less bracing deepens the tone.
The standard brace sizes are 1/4" and 5/16". The smaller braces are more flexible; they allow the top to move more with less force, but that means the top reaches its maximum volume sooner. Smaller bracing is usually better for fingerstyle, and bigger for picking.
Pretty much all you'll find in everything but the highest-end vintage recreations in X-bracing. You can see the "X" through the soundhole. It's the stiffest of the standard bracings, which allows the top to be thinner and lighter. In practice, it gives a great balance of volume and response - the exact reason it's the standard.
"Forward-shifted" X-bracing was the original design used by Martin before 1938. It had one less brace than the current standard, and allowed more flexibility behind the bridge. It was louder and deeper sounding than the current X, but they discontinued it because the strings of the time (14 or 15 gauge in today's terms) warped the tops. It's now used on purpose-made bluegrass dreadnaughts with the caveat "for light or medium strings ONLY!"
Most X-bracing these days is scalloped. Scalloping increases the flexibility of the brace slightly, but mostly is done to lower weight. A guitar with scalloped braces will be louder, deeper, AND more responsive than unscalloped. A better tone in nearly every respect. Some players still choose unscalloped if they prefer a more focused, tight tone and are willing to give up a little volume, or they want a period-correct 1930s-50s guitar.
Ladder bracing was the standard before X-bracing, and dates back to before steel strings (though it was used by some companies through the 60s). Being that it was designed for gut strings, it isn't the best for steel. The sound is a little dark, midrangey, woody, and compressed. Players who choose it usually do so because they want a period-correct guitar for blues or roots music. The sound is less rich than X-bracing, but it does have an appealing "old-timey" quality.
Fan-bracing is used on classical guitars and is designed for the greatest flexibility on instruments that will not have much string tension.
Back braces have less of an effect, and can even be optional. Some Taylor guitars with laminate backs forgo bracing altogether, in favor of a slight arch for strength. Other larger guitars use big, thick braces to keep the wide wood pieces from splitting. I have a guitar from the Depression where the back is braced with glue-soaked cloth! More bracing tightens the tone and increases projection, while less bracing deepens the tone.
Part IV - Ebony vs. Rosewood:
Ebony was used by Martin originally. The purpose was not so much sound as strength; an ebony bridge would not split under string tension and and ebony fretboard made the neck stiffer and straighter (very important in the days before adjustable truss rods). If you've ever lifted a piece on ebony, though, you know it's also very heavy. Heavy enough to dampen the sound. Imagine putting a metal bridge on an acoustic - the sound would become quieter, brighter, and have more sustain. The same shift happens, to a smaller extent, when comparing rosewood to ebony. Ebony is heavier and makes for a brighter sound with more sustain, but its heaviness also dampens some vibrations. This, combined with its cost, is why most makers are transitioning to the lighter rosewood.
A good quality piece of ebony looks almost like plastic - very dark and smooth.
Ebony was used by Martin originally. The purpose was not so much sound as strength; an ebony bridge would not split under string tension and and ebony fretboard made the neck stiffer and straighter (very important in the days before adjustable truss rods). If you've ever lifted a piece on ebony, though, you know it's also very heavy. Heavy enough to dampen the sound. Imagine putting a metal bridge on an acoustic - the sound would become quieter, brighter, and have more sustain. The same shift happens, to a smaller extent, when comparing rosewood to ebony. Ebony is heavier and makes for a brighter sound with more sustain, but its heaviness also dampens some vibrations. This, combined with its cost, is why most makers are transitioning to the lighter rosewood.
A good quality piece of ebony looks almost like plastic - very dark and smooth.
Part V - Laminate vs. Solid:
Is solid wood better than laminate? Well, it's more expensive.
Laminate materials are stiffer at a given thickness than solid woods. In theory, this would allow a guitar to be braced more lightly and achieve similar resonance to solid woods. However, this doesn't usually happen. I can think of no reason that a laminate guitar couldn't sound as good as a solid one - perhaps even better, given laminate's stiffness to weight ratio. What usually happens, though, is that laminates are placed on lower quality guitars which sound poor for a whole litany of reasons.
In the end, it's become a matter of marketing. Making a good quality guitar is expensive, regardless of materials. Players are not likely to invest the money in a guitar made of what's perceived to be second-class stuff. When looking at the labor cost of building a guitar, the slight additional cost of solid woods (compared to the marketing value) makes using laminates irrelevant.
Where laminates become useful is in large-run, mechanized factory settings where maximum consistency is required. That's why they're found on cheap guitars.
As a matter of trivia, John Lennon used his J-160E for most of his acoustic recordings from 1963 on. That guitar used a laminate top.
Is solid wood better than laminate? Well, it's more expensive.
Laminate materials are stiffer at a given thickness than solid woods. In theory, this would allow a guitar to be braced more lightly and achieve similar resonance to solid woods. However, this doesn't usually happen. I can think of no reason that a laminate guitar couldn't sound as good as a solid one - perhaps even better, given laminate's stiffness to weight ratio. What usually happens, though, is that laminates are placed on lower quality guitars which sound poor for a whole litany of reasons.
In the end, it's become a matter of marketing. Making a good quality guitar is expensive, regardless of materials. Players are not likely to invest the money in a guitar made of what's perceived to be second-class stuff. When looking at the labor cost of building a guitar, the slight additional cost of solid woods (compared to the marketing value) makes using laminates irrelevant.
Where laminates become useful is in large-run, mechanized factory settings where maximum consistency is required. That's why they're found on cheap guitars.
As a matter of trivia, John Lennon used his J-160E for most of his acoustic recordings from 1963 on. That guitar used a laminate top.
Part VI - Finishes:
When it comes to urethane vs. lacquer, I can't cover it any better than luthier Dana Bourgeous' excellent page:
http://www.pantheonguitars.com/Dana%20B ... _frets.pdf
In summery, he prefers urethane to lacquer, but for extremely good reasons. I've played a few of his guitars, and they were about as perfect as one could imagine.
Some factories spray finishes very thick in order to easily get a high gloss and lessen the chance of damage during shipping - this is murder for an acoustic guitar. Other factories are able to get just as high a gloss with a very thin finish. And a satin finish can be just as thick as a gloss! The sheen is not a good indication of how thick the finish is, but you can feel when it's too thick.
Some of the highest-end guitars use a traditional hand-rubbed finish. It's a time-consuming process, but allows a very thin finish that has a nice, though subdued, shine. Mostly, though, "hand-rubbing" is something for which an inflated premium can be charged on very expensive guitars.
Sunburst is also something to look at closely, especially on vintage guitars from the 30s, 40s, and 50s. The reason it came into use on acoustics was because the dark outer finish could be used to hide flaws on lower-quality pieces of wood (remember - the best spruce was being sent to Britain to make planes). Think about that when you see an original J-45 with a super-dark burst!
When it comes to urethane vs. lacquer, I can't cover it any better than luthier Dana Bourgeous' excellent page:
http://www.pantheonguitars.com/Dana%20B ... _frets.pdf
In summery, he prefers urethane to lacquer, but for extremely good reasons. I've played a few of his guitars, and they were about as perfect as one could imagine.
Some factories spray finishes very thick in order to easily get a high gloss and lessen the chance of damage during shipping - this is murder for an acoustic guitar. Other factories are able to get just as high a gloss with a very thin finish. And a satin finish can be just as thick as a gloss! The sheen is not a good indication of how thick the finish is, but you can feel when it's too thick.
Some of the highest-end guitars use a traditional hand-rubbed finish. It's a time-consuming process, but allows a very thin finish that has a nice, though subdued, shine. Mostly, though, "hand-rubbing" is something for which an inflated premium can be charged on very expensive guitars.
Sunburst is also something to look at closely, especially on vintage guitars from the 30s, 40s, and 50s. The reason it came into use on acoustics was because the dark outer finish could be used to hide flaws on lower-quality pieces of wood (remember - the best spruce was being sent to Britain to make planes). Think about that when you see an original J-45 with a super-dark burst!
Part VII - Old vs. New:
We are living through the great golden age of acoustic guitars. The guitars made today, in general, are better than anything made at any time in the past, with a few caveats:
New guitars typically use synthetic glues rather than traditional Hide glue. The difference in sound is inconsequential, but all modern glues used in guitar making are more likely to creep or release under heat stress than Hide glue. Additionally, guitars made with hide glue are far easier to repair. Most companies don't use hide glue anymore because it's hard to work with and dries slowly compared to light or chemically cured glues.
Guitars made before WWII often used Adirondack spruce, but, like anything, whether or not that sounds better to you is a matter of opinion. Bluegrass players love it for the volume, but a fingerstylist would probably find it too stiff.
A lot of modern guitars are just made to be products - produced as quick, cheap, and salable as possible. Obviously, these can't be compared to a well-made old guitar. Apples-to-apples, modern guitars are better. For example, I've never played a vintage J-45 that sounded better than a new one and, adjusted for inflation, their costs are similar. Considering the adjustable-bridge and ceramic-saddled J-45s from the 50s and 60s, there's no question the new ones are better.
Martin is the exception. Their best and most expensive new guitars are fine, but most of their line is quickly turned-out, cheaply-made product. Their wood selection is especially inconsistent, and many models sport ponderously obvious design flaws. Buyer beware.
A 70-year-old guitar has been getting broken in for 70 years - no way around that!
We are living through the great golden age of acoustic guitars. The guitars made today, in general, are better than anything made at any time in the past, with a few caveats:
New guitars typically use synthetic glues rather than traditional Hide glue. The difference in sound is inconsequential, but all modern glues used in guitar making are more likely to creep or release under heat stress than Hide glue. Additionally, guitars made with hide glue are far easier to repair. Most companies don't use hide glue anymore because it's hard to work with and dries slowly compared to light or chemically cured glues.
Guitars made before WWII often used Adirondack spruce, but, like anything, whether or not that sounds better to you is a matter of opinion. Bluegrass players love it for the volume, but a fingerstylist would probably find it too stiff.
A lot of modern guitars are just made to be products - produced as quick, cheap, and salable as possible. Obviously, these can't be compared to a well-made old guitar. Apples-to-apples, modern guitars are better. For example, I've never played a vintage J-45 that sounded better than a new one and, adjusted for inflation, their costs are similar. Considering the adjustable-bridge and ceramic-saddled J-45s from the 50s and 60s, there's no question the new ones are better.
Martin is the exception. Their best and most expensive new guitars are fine, but most of their line is quickly turned-out, cheaply-made product. Their wood selection is especially inconsistent, and many models sport ponderously obvious design flaws. Buyer beware.
A 70-year-old guitar has been getting broken in for 70 years - no way around that!
