Scale size is an typically missed design variable that has a substantial influence on the sound and really feel of the guitar. Right here’s a information to understanding scale size on acoustic guitars.

I would like your assist to grasp scale size. Why are there so many alternative variations, how is scale size measured, and the way does it have an effect on the tone of the guitar? What gauge strings are finest for various scale lengths? Why ought to this measurement matter to me, and the way ought to it think about when purchasing for a guitar? —Bob Lang, Starksboro, VT

Earlier in my profession, I labored with Veillette Guitars, an organization that focuses on uncommon scales and tunings, so this subject is one I notably take pleasure in. Within the easiest phrases, scale size refers back to the size of the lively/vibrating portion of the open string, between the nut and saddle. Amongst acoustic guitars, the commonest scales are clustered round 25.4–25.5 inches and 24.75 inches. Nevertheless, to find out the size of a guitar, you’ll be able to’t simply measure from nut to saddle, because the bridge saddle positions are moved or compensated away from the theoretical scale level to right intonation. Essentially the most correct solution to calculate scale is to measure the gap from the nut to the middle of the twelfth fret and double the outcome.

The essential rule of scale size is easy: For any given tuning and set of strings, longer scales have larger stress. As soon as once more, it’s vital to notice that this solely applies to the realm of string that’s vibrating between the nut and saddle. The string past these factors (referred to as the afterlength in violin-family devices) can have an effect on facets of how the string feels, as a higher afterlength presents extra stretch than a brief one, however doesn’t influence the stress of the string at its goal pitch.

When doing a setup, scale size is a vital consideration. Devices with shorter scales will be extra demanding for a variety of causes: The decrease stress means fret buzzes will be precipitated extra simply, and the intonation is commonly trickier to dial in precisely. A participant accustomed to low motion on a 25.5-inch fretboard could also be comfy with barely larger motion on a 24.625-inch instrument, whereas somebody who normally performs quick scales could need to select a lighter string gauge in the event that they purchase a longer-scale guitar.

It’s not unusual for gamers to marvel how a lot distinction a change of three/4 of an inch or much less actually makes. Let’s contemplate the general stress of a typical mild (.012–.053) string set. On a 25.5-inch scale fretboard, the mixed stress at commonplace tuning is 160.5 lbs., whereas at 24.75 inches the stress is 151.24. Subsequently, a three-percent change in scale size may end up in a six-percent change in stress. By comparability, a set of .011–.052 strings provides as much as 148.6 kilos. The result’s that the stress of .012s on the shorter scale will probably be very akin to the .011s on the longer scale.

Alongside string stress, you should additionally contemplate string flexibility. Thicker strings are much less versatile, as are shorter lengths of string. As a string loses its flexibility, it begins to exhibit much less correct intonation, which is as soon as once more why the thick low strings require higher compensation than the skinny excessive strings. Excessively stiff strings additionally are inclined to sound much less musical, with odd harmonics and overtones that don’t relate to the notes being performed.

Low bass notes, subsequently, are higher reproduced with lengthy strings than with quick ones, because the size permits a thinner, extra versatile string for use. Treble strings, alternatively, can sound skinny, harsh, and unsightly if the stress is just too excessive, and lots of gamers favor the nice and cozy, thick tone of the trebles on shorter scales. Subsequently, the builder and participant should discover the comfortable medium between clear, well-behaved bass strings and nice, musical trebles by selecting the perfect mixture of scale and string gauges. The best instance of that is the grand piano, which makes use of a for much longer scale size for the low bass strings than the treble strings. Think about how completely different the strings would have to be to be able to make that vary work with a single scale size!

Though the guitar has significantly much less vary than the piano, there are nonetheless circumstances the place a shorter scale is just not ideally suited to the participant’s wants—these may embody prolonged tunings with low D or C notes, or guitars with greater than six strings. In an try to enhance bass-string response with out compromising the standard of the excessive notes, some trendy makers provide multiscale or fan-fretted devices, which have longer bass string scales and shorter trebles. Such devices have frets that aren’t parallel, which could be a bit intimidating at first look, however this design is gaining recognition with gamers who respect the extra even stress and response it might probably provide with extended-range tunings. California luthier Ralph Novak is broadly credited with proving and popularizing this modern strategy within the customized guitar world, and bigger producers at the moment are following go well with with manufacturing multiscale devices.

Taking note of scale size when purchasing for a guitar will be very useful. Some guitars will simply really feel proper, and the size is commonly an enormous a part of that. The fret-to-fret variation between completely different scales is pretty small—for instance, between the 2 scales mentioned above, the distinction in distance between the primary and second frets is just 40 thousandths of an inch. However even these small variations will be felt and appreciated by most gamers. For a guitarist who has all the time performed Gibsons, for instance, the longer scale of a Martin dreadnought or OM could nicely take some adjustment. Holding this in thoughts when evaluating and evaluating guitars permits the participant to make extra correct judgments about which facets of the guitar are impacting the enjoying expertise—motion will be lowered, however scale size is mounted, and if a guitar feels uncomfortable, it’s helpful and vital to grasp why.

Guitar designers typically regulate scale size to optimize an instrument for a selected function—for instance, jazz archtops with pickups typically have shorter scales, which yield thicker, hotter sounding trebles and heat basses with a clean assault. Against this, a builder aiming for the bluegrass flatpicker market will probably use an extended scale to get the added punch and quantity that the upper string stress can produce. When constructing a long-scale guitar, the builder should additionally anticipate the upper stress and brace accordingly, or the instrument could not survive in the long run. That is one purpose many fingerstyle gamers have gravitated in the direction of 00- and 000-style guitars, as their shorter scale (24.9 inches) permits lighter bracing, which yields a extra delicate and dynamic instrument.

On the excessive finish of the size spectrum are baritone guitars (see “Taking up the Tweener” within the March/April 2020 problem), which normally vary from 27–30 inches in scale and are designed to be tuned down so far as a fifth beneath an ordinary guitar. The heavier string gauges, mixed with the lengthy scale, could make the low notes on these guitars fairly spectacular—and assist as an example the mixed impact of gauge and scale on the standard and character of the guitar’s tone. Capoing a baritone again as much as E will lead to the identical tuning as an ordinary guitar, however with a really completely different timbre and tone.

Scale size is without doubt one of the elementary constructing blocks of a guitar’s recipe, with a wide-ranging influence on the texture, tone, and efficiency. Understanding the way it interacts along with your setup, string alternative, and enjoying fashion will make it a lot simpler to correctly regulate your guitar, and will assist information you in the direction of an instrument that feels excellent.

This text initially appeared within the Might/June 2020 problem of Acoustic Guitar journal.