Multiscale (Fanned-Fret) Fretboards: What They’re For, and What They’re Not

Multiscale Fretboards: What They Are For and What They Are Not

Multiscale fretboards are becoming increasingly common, particularly in modern metal, progressive music, extended-range guitars, and basses. Although they are sometimes presented as a relatively recent innovation, the basic concept is centuries old.

One early Western example is the orpharion, a wire-strung instrument built during the Renaissance. Surviving examples date to the latter half of the sixteenth century. The instrument used different string lengths across the fingerboard, along with very low frets and a scalloped fingerboard. These design choices were related to the behavior of its relatively low-tension metal strings and the difficulty of keeping them playing cleanly and accurately in tune.

The modern application of multiscale design is based on a similar mechanical problem. It allows the builder to alter the scale length of individual strings according to their diameter, tuning, and desired tension.

For a given string, increasing scale length increases tension at the same pitch. Decreasing scale length reduces it. This becomes particularly useful when an instrument covers a wide pitch range.

A conventional guitar uses one scale length for every string. This is normally a reasonable compromise. As tunings become lower, string counts increase, or the difference between the lowest and highest strings becomes greater, that compromise becomes more obvious.

A scale length that works well for the treble strings may leave the bass strings excessively loose. Increasing the scale length enough to correct the bass side can then make the treble strings unnecessarily stiff. String gauge can compensate for some of this, but there are practical limits to how far that solution should be taken.

A multiscale fretboard allows those two requirements to be treated separately.

A guitar described as having a 27"-25" multiscale, for example, normally has a 27" scale on the bass side and a 25" scale on the treble side. The strings between them receive intermediate scale lengths. The resulting fret positions form the familiar fan.

This is the principal reason I believe multiscale exists as a useful design tool: it allows the scale length to be matched more appropriately to the string.

It is also important to be precise when discussing intonation. Multiscale does not automatically make an instrument play in tune. Accurate fret placement, nut work, saddle compensation, string construction, action, relief, and player technique still matter.

What multiscale can do is improve the operating conditions of a string that would otherwise be poorly suited to its scale length. A low string that requires excessive diameter to reach usable tension can become increasingly stiff and behave less ideally. Giving that string additional scale length allows the builder to achieve the desired tension with a more appropriate string diameter. This can improve its response and make compensation more manageable.

The subject becomes less clear when ergonomics enters the discussion.

Multiscale fretboards are frequently advertised as being inherently ergonomic. I do not think that is a useful generalization.

Some players find certain multiscale layouts comfortable because the fret angles happen to correspond well with the position of the hand and wrist in particular areas of the neck. Other players experience exactly the opposite.

A sufficiently aggressive fan near the nut can make first-position playing noticeably less familiar, particularly for someone who has spent years playing conventional instruments. Large stretches and some chord shapes can become more awkward rather than less.

This does not mean that multiscale cannot have ergonomic advantages. It means that ergonomics are dependent on the particular layout and the player. They are not an inherent property of a multiscale fretboard.

There is another part of the design that deserves more attention than it usually receives: the perpendicular fret.

On most multiscale fretboards there is a location where one fret sits perpendicular to the centerline of the instrument, much like the frets on a conventional guitar. This is commonly called the neutral or perpendicular fret.

The position of that fret is not dictated solely by the two scale lengths.

Imagine the bass and treble scale lines lying next to one another. One can be moved longitudinally relative to the other while their individual scale lengths remain unchanged. Moving them changes the orientation of the fret fan and therefore changes where the perpendicular fret occurs.

Two guitars can consequently have identical bass and treble scale lengths while having noticeably different fret angles and playing characteristics.

The perpendicular fret can theoretically be placed almost anywhere, including outside the physical limits of the fretboard, although I see little practical reason to design an instrument that way.

Its location has a substantial effect on how the neck feels.

Moving the perpendicular fret toward the bridge tends to reduce the fan in that area while increasing the angle toward the nut. Moving it toward the nut does the opposite. This is why simply knowing that an instrument is 27"-25.5", for example, does not tell you everything necessary to understand how it will feel.

For that reason, I think trying a multiscale instrument before buying one is particularly valuable.

There is no universal multiscale specification. Builders choose different scale ranges, different perpendicular fret positions, different string gauges, and different intended tunings. Some of those decisions are driven by string mechanics. Others are aesthetic choices, attempts to create a particular playing feel, or simply decisions inherited from an existing design.

The useful question is not whether a guitar is multiscale.

The useful question is why it is multiscale.

A builder should be able to explain what problem the chosen scale lengths are solving. What tuning was the instrument designed around? What string gauges are expected? Why does the bass side need its particular length? Why does the treble side need its length? Why was the perpendicular fret placed where it was?

If those decisions cannot be explained in relation to the strings and the intended tuning, I would be cautious about assuming that the presence of a multiscale fretboard represents an improvement.

Like most things in guitar construction, more extreme specifications are not automatically better specifications.

The purpose of multiscale is not to create the largest possible difference between the bass and treble scales. It is to use different scale lengths where different scale lengths are useful.

The Bezard Multiscale Philosophy

For my own guitars, the philosophy is simple.

With a readily available string set, I first ask whether the bass side is too loose or the treble side is too tight.

From there, I determine whether the practical solution is to lengthen the bass scale, shorten the treble scale, or do some combination of the two. I then try to determine how much change is actually necessary and avoid going beyond it.

I do not see a reason to use a more aggressive multiscale simply because the design allows it. Once the desired string behavior has been achieved, additional fan becomes unnecessary.

After establishing the scale lengths, I generally place the perpendicular fret relatively close to the nut. This keeps the fret angles farther up the neck comparatively familiar while still allowing the scale lengths to do what they need to do.

For me, multiscale is not an aesthetic feature and it is not a specification that needs to be maximized. It is a way of assigning an appropriate scale length to each string according to its gauge, tuning, and required tension.

Once that problem has been solved, the design has done its job.