650mm vs 640mm short scale classical guitar
what's the difference and which should I get?
The difference between 650mm and 640mm classical guitar is the length of the string from the nut to the saddle, also known as the scale length. The scale length affects the tension, tone, and playability of the guitar. A shorter scale length means lower tension, warmer tone, and easier stretches.
A longer scale length means higher tension, brighter tone, and harder stretches. The difference of 10mm may not seem much, but some players can feel and hear the difference. The choice of scale length depends on your personal preference, hand size, playing style, and repertoire.
Don’t necessarily confuse scale length with a smaller body guitar. Just because the scale length is smaller doesn’t mean the luthier built a significantly smaller instrument (although sometimes they do).
Recently there were many guitars with a scale length of 660 or 665 mm – now they are rare and today’s standard is 650 mm.
On the one hand, this is very good because it provides variety and creates a connection between guitar and body type. People should feel comfortable playing the instrument and not be forced into situations where they struggle with the size of the instrument. On the other hand, many classical instruments, especially orchestral ones, only exist in one standard scale (like violin, cello, piano(!) and there is no question whether there should be different Steinway “scales” for musicians of different body sizes. When it comes to classical guitars, this is the famous photo of Segovia’s wife in a huge spread sheet, taken with her tiny hands… So it’s laziness, or maybe modern guitars just can have a shorter scale without any sonic flaws?
Advantages of short scale guitars
Disadvantages of short scale guitars
…I commonly encounter the belief that scale-lengths of 645 mm or 640 mm are sufficient to accommodate players struggling with 650. There are surely players for whom these lengths are optimum, but I think the value of even shorter lengths is underrated. Take a guitar of 650 scale and capo at the 1st fret. You now have a scale length of 613.5. If your hands are small and you are having a struggle with 650, try this. In addition, if you can have a local luthier make a new nut for your guitar with closer string spacing, you might find an even better fit. (The normal string spacing at the nut is about 43-44 mm, E to E, center to center. A person with very small hands might benefit with spacing as close as, say, 37 mm. It is usually best to keep string spacing at the saddle unchanged, since no matter how small the hands, free-stroke playing requires about the same amount of space between the strings.)
I have great faith in shorter scale lengths and feel they have been unjustly “belittled” for having reduced power and volume. For people with smaller hands the increased playability could far outweigh any perceived loss of power. This loss can occur, in theory, because of reduced string tension or reduced box dimensions. Yet by using higher tension strings the first objection is overcome, and as for the effects of reduced box size, bigger is not always louder. Every design will have an optimum box size and shape to maximize volume, but a smaller box may actually increase projection or quality of sound. Some of the smaller Torres and Hauser I guitars faired quite well in the concert hall. These sizes are easy to adapt to shorter scale lengths. I reduce the size of the plantilla by only about 3-5 mm around the perimeter for both my 630 and 613.5 scale guitars. The sound can be very lovely and without one of my 650s for direct comparison, diminished volume is not obvious…
I have a real affection for shorter scale guitars. Somewhere along the line some people have arrived at the assumption that a longer string will produce more power, and conversely that a shorter string will produce a smaller sound. Not necessarily true! In the 60s, 70s and 80s a lot of Spanish guitars had a 660mm string length and a lot of Ramirez’s had 665mm string length, presumably with the intention of making the guitar louder and more powerful. There are many beautiful sounding instrument with that kind of string length, but they are hard to play. Now the standard is 650mm. I think guitarists got tired of fighting with hard action instruments and wanted a more cooperative neck. A shorter string reduces the left hand reaches, and reduces the overall tension of the instrument, because the with the shorter length the string doesn’t have to be pulled as tight to reach pitch. Maybe this is counter intuitive , but this lower tension can actually allow the top of the guitar to move more freely, and actually produce more sound.
In a 640mm instrument we take this just a little bit farther. The difference is slight, maybe imperceptible, but this difference can tip the scales of comfort for many people. There may be a general perception that a 640 is a “little” guitar, or under powered and weak, but this just isn’t necessarily so. Before trying it I was skeptical, but over the years some of the best guitars I’ve made have been 640 scale. There tends to be an added warmth, malleability of tone, and cooperative feeling in both right hand tone production and left hand facility. And there is no sacrifice of volume. I’ve never had anyone, including outstanding players, comment about any inadequacies in a 640 scale. They just don’t notice. In fact I’ve seen them in “blind tests” chosen above 650 scales many times.
I’ve found that scale length does not really alter the sound much, at least not with my own guitars, in the context of say 640, 650, or 660 scale lengths. If you go much shorter, for example to a 610, 620, or 630, you’re going to get some changes, but usually the size of the guitar body has been scaled down as well, so we’re now introducing other factors that affect the sound beyond just scale length.
A longer scale length means a longer, heavier string. More tension will be required to bring this heavier string up to the same pitch as a lighter string. The stiffer tension will be felt by the player. I think this tactile change is a bigger difference than any tonal one. Conversely, a shorter scale will require less tension to reach the same pitch, and the string will feel more slack to the fingers.
As a general rule, a 640 scale guitar strung with hard tension D’addarios will feel similar to a 650 scale strung with medium tensions.
But as far as sound goes, the overall character of the woods, bracing, and other design elements, are far more important to creating the desired tone. Don’t let anyone tell you that a 640 scale will have dramatically less power or bass response than a 650 or a 660 scale length.
There are many classical guitar players who prefer or use a 640mm scale guitar, either for comfort, tone, or technique. Some of them are:
David Russell: He plays a 640mm scale guitar made by Matthias Dammann, a German luthier who pioneered the double-top construction1. Russell is a Grammy award-winning classical guitarist who has recorded over 20 albums and performed in prestigious venues around the world2.
Sharon Isbin: She plays a 640mm scale guitar made by Thomas Humphrey, an American luthier who invented the Millennium bracing system and the elevated fingerboard. Isbin is a multiple Grammy award-winning classical guitarist who has collaborated with artists from various genres and founded the guitar department at the Juilliard School.
Ana Vidovic: She plays a 640mm scale guitar made by Jim Redgate, an Australian luthier who specializes in lattice-braced and double-top guitars3. Vidovic is one of the most accomplished and popular classical guitarists of her generation, with a repertoire that spans from Bach to Piazzolla.
These are just some examples of famous classical guitarists who play 640mm scale guitars. There are many others who also enjoy the benefits of a shorter scale length, such as Pepe Romero, Xuefei Yang, Berta Rojas, and more.