Tech Talk Scale Length 101 How it Affects Your Tone

Tech Talk Scale Length 101 How it Affects Your Tone

One of the things that guitar players love to talk about more than anything else is tone. Get a guitarist started on the subject of tone and watch out! These guys (and girls) can talk for hours about pedals, amps, hand wound pickups, and any manner of other topics relating to their ideal tone. One subject that I don’t hear discussed a lot, however, is scale length. Many players have only a rudimentary knowledge of the concept of scale length and how it effects the playability and tone of their instrument. There have been several different types of scale lengths used in various guitars through the years. For purposes of this article, we’re going to look at the three most popular scale lengths: the 25.5-inch ‘Fender’ scale, the 24.75-inch ‘Gibson’ scale, and the 25-inch ‘PRS’ scale.

Scale length is calculated by measuring the distance from the nut to the center of the twelfth fret, and then doubling that measurement. If your guitar has a zero fret, the distance should be from the center of the zero fret to the center of the twelfth fret. All guitars have a little extra compensation length added to the string. For example, if your Les Paul is a 24.75-inch scale, the actual length will be closer to 24-7/8”. The main reason this is done is to compensate for the slight stretching effect of pushing a string down onto the fretboard. Thick strings are more susceptible to this than thinner strings, which is why most bridges are set at an angle. This compensation, combined with the angled bridge, is the reason that you can’t simply measure from the nut to the bridge to calculate your scale length. Now that you have a basic understanding of how scale length is calculated, let’s talk about how it affects the playability of your guitar of choice. Basically, a longer scale length will create a ‘tighter’ feel, and a shorter scale length will create a ‘looser’ or ‘slinkier’ feel. The string gauge you choose will definitely have an effect on the feel of the instrument as well, but knowing how the scale length affects the playability of your guitar will help you determine which strings to choose. Many players will use different gauge strings on different scale length guitars. For example, TMG editor Derek Williams uses .010 gauge strings on his Gibson-style guitars, and .009 gauge strings on his Fender-style guitars. For some players, mixing and matching string gauges among different scale length guitars like this can help keep the feel of their instruments consistent. It all boils down to what feels good to you and helps you play your best.

Someone once told me that if you show up to a gig with a Les Paul and a Strat, you should be able to cover most of your tonal variations with those two instruments. Obviously there are many reasons that those two guitars have different sounds. A Les Paul, for example, is generally made of mahogany and maple, has a set-in neck joint, and humbucking pickups. A Stratocaster is usually made of alder or ash, has a bolt-on neck, and uses single coil pickups. Some of these choices were made for aesthetic reasons, some for playability, and some for ease of manufacturing and repair. Most of these choices, though, were made with an ear for tone. Let’s take a look at how the scale length of these two instruments affects their tone, and you’ll begin to see how the other choices of the innovators of these two particular guitars underscores those differences in tone. Most musicians are familiar with the term “A-440”. For the uninformed, A-440 refers to the A above middle C on a piano keyboard. The 440 refers to the frequency of this particular note, which vibrates 440 times per second, more commonly referred to as 440 Hz. If you’re familiar with the concept of frequencies, you’ll know that each octave up or down from that pitch produces a doubling or halving of that frequency. For example, the next octave up produces an A at 880 Hz, and an octave down produces an A at 220 Hz.

One of the things that makes the guitar such a unique instrument is it’s ability to produce complex overtones. Almost everything in life has a native resonant frequency, and the various woods of a guitar are no exception. This is most noticeable on acoustic guitars. When you strum a chord, you’ll hear the complex tones created by the interaction of strings at various frequencies with the wood of the instrument. So how does this relate to scale length? Good question. Remember our discussion of frequency from the last paragraph? The longer a string is, the more harmonic content it can generate. If you grab a guitar and play an open string, you should be able to hear the harmonics subtly change as the string rings out. If you play the twelfth fret harmonic on the same string, you’ll hear the same effect, but obviously at different frequencies. On a Fender-scale guitar, the string is longer, which gives it more of a chance to produce harmonics. This results in a tone that is brighter and has more sparkle. The choice of hard woods, like alder and ash, are designed to accentuate this. As the scale length gets shorter, so does the distance between the nut and the bridge. A shorter string pushes the harmonic content into a shorter space, much like putting a subtle compressor on your guitar would do. This results in a tone that has more punch and power, which is why many rock players prefer the tone of the shorter Les Paul scale. Also, because of the fewer harmonic overtones created in a shorter scale length, the tone sounds warmer. Softer woods such as the mahogany used in many Les Pauls accentuates the warmth of the shorter scale length. To keep the sound from being TOO dark, many Les Pauls have a maple cap, which helps to bring some brightness back into the sound.

A few years ago, I had the great honor of spending a bit of time with Paul Reed Smith. Regardless of how you feel about PRS guitars, Paul is a great innovator who has achieved something very special in the musical instrument marketplace. In an industry dominated by Fender and Gibson, the PRS brand became a major player in the industry, something no other manufacturer has really done. Much of this is due to the fact that PRS guitars feel and sound different than either Fender or Gibson guitars, thereby filling a niche in the marketplace that had previously gone unserved. Paul was kind enough to share his philosophy on guitar design with me when I met him. PRS guitars are designed to be balanced. If you remember, Fender guitars have a brightness to them, and Gibsons have a warmer tone with more punch. Paul’s philosophy is to make the guitar and pickups completely balance with each other, with no emphasis in either direction. He feels that this creates a more versatile instrument. The popularity of PRS guitars in a wide variety of genres seems to underscore the effectiveness of this philosophy.

One of the major ways that PRS achieves the balanced tone of their guitars is by a subtle shifting of scale length. Almost all PRS guitars are built using a 25-inch scale length, roughly halfway between the scales of Gibson and Fender guitars. This scale length captures some of the punch and power of the shorter 24.75-inch scale, while retaining some of the bell-like overtones of the longer 25.5-inch Fender scale. This is the same scale length used on many Dobro resonator guitars, as well as Danelectro instruments. I hear comments from some players that PRS’s ‘just don’t feel right’, which is probably due to the initial unfamiliarity with this middle scale length. For those who love the PRS quality but have trouble adjusting to the feel of the scale length, PRS has introduced models like the 305 with a 25.5-inch scale, and the SC 245, which has a shorter 24.5-inch scale. Which guitar you pick and which scale length you prefer ultimately comes down to the type of music you play, the sound you want to achieve, and what feels the best to you. Whatever you choose, there are a ton of great options available to help you find your ultimate tone. Happy hunting.