How guitar design affects sound

There’s a common theory that if you stretch guitar strings to pitch over a guitar pickup, what it’s all anchored to won’t make the slightest difference to the sound.

It’s hard to argue against that when you see things like Justin Johnson playing his shovel guitar:

…and Rev. Peyton with his axe guitar:

Many an internet argument has been slugged out over the validity of this concept. Guitar design does make a difference though, and hopefully I can demonstrate why and to what extent by comparing a few.

Scale Length and Pickup Placement
First things first, go and get your guitar. Yes, right now. I’ll wait.
Don’t worry about plugging it in.

Now, if you pick the strings close to the bridge, you’ll notice that there’s a fair bit of tension and the sound is fairly nasal and trebly. If you do the same thing closer to the neck you’ll notice much less tension and far less treble. It stands to reason then that a pickup in the bridge position is going to produce more top end than a pickup in the neck position.

That being the case, consider scale length for a moment (the length of the string from the nut to the 12th fret x 2). A guitar with a longer scale length is going to have more space between the neck and the bridge. The further the bridge pickup is from the neck, the more top end it’s going to offer up. Likewise, the further the neck pickup is from the bridge, the warmer or darker the tone will be.

Fender Strats and Telecasters are known for their bright tones. While there are a heap of factors responsible for this, the 25.5 inch scale length certainly plays a role. Gibson Les Pauls have a much warmer tone by comparison, and while again, there are many contributing factors at play, the much shorter 24.75 inch scale length is one of them.

Longer scale length means extra string tension, which will influence the way you play. The amount of downward pressure you have to apply to the strings with your fretting hand as a result will influence the tone, and how much vibrato you feel inclined to use. It could also influence how hard you hit the strings with your picking hand.

String Length
Beyond scale length, it’s worth pointing out that the required string length will differ from guitar to guitar. Scale length only matters up until the string passes over the saddle of the bridge, but the string is longer than this.

In some cases the strings will terminate at a tailpiece a long way from the bridge. Some will pass through the body of the guitar, and others stop short just behind the bridge.

Likewise, different headstock designs place the tuning pegs at different distances from the nut.

String length contributes to string tension, affects sustain, and influences how you interact with the guitar.

The Bridge
The full weight of a vibrating string is taken up by the saddle of the bridge. Because of this, the bridge transfers the strings’ vibration to the body of the guitar. Different bridge designs handle this differently, with some transferring vibration more efficiently than others. This will ultimately have an effect on note sustain, and the tonal characteristics of those notes as they gradually fade out.

Size and Weight
From there, the tone of the sustained note (and the length of its sustain) is influenced by the wood of the body that the bridge transfers this vibration to. Most folks can agree that, to a certain extent, the more wood (and more weight) your guitar has, the more sustain it will likely have.

Now for one of the most bitterly disputed concepts of guitar tone ever to be discussed on the internet:

Tone Wood
Different species of timber carry vibration in different ways, and this (reportedly, through subjective observation and not measurable science) contributes different tonal qualities. It’s perfectly OK if you don’t agree with this, there’s no need for death threats in the comments section.

It’s important to note that wood won’t add qualities to your sound. The influence of timber in your tone is reductive.

For example, a harder wood (like maple) will absorb lower frequencies more, allowing for a brighter sound. A softer wood (like mahogany) will absorb higher frequencies better, allowing a warmer sound to resonate.

When the two are combined (like a Les Paul with a mahogany slab and a carved maple top), the high and low frequencies are absorbed, resulting in a sound which favours mid frequencies.

The tonal impact of timber species is so subtle that a slight tweak of a tone knob would completely over ride its influence. So if that’s the case, is it worth worrying about wood?

Well, yes. Here’s why:

It all adds up
Many aspects of guitar sound make such a small contribution to your overall tone that some would argue that it’s trivial. The average person in the audience won’t notice the tonal difference if you swap guitars mid set to one with a different timber species or bridge design.

Every little bit adds up together though.

The audience will notice the headline act “just sounds better”. They don’t know it’s because the band has carefully chosen every piece of equipment to have complimentary tonal characteristics. They just assume it’s because the sound guy phones it in for the opening act.

The tonal characteristics of any one piece of equipment should be considered when deciding what to add to your rig as a whole to get the sound you’re after. There’s no point buying something and then tweaking the rest of your gear to fight against its tonal contribution.

The Moral of the Story
When choosing a guitar, consider the sound you’re after. What amp will you be plugging it into? What sort of sound will the guitar need to have to interact with the amp to produce the overall sound you want?

You should also choose a guitar that feels comfortable to play.

When shopping for a guitar and trying them out in the store, make sure that you plug into the sort of amp you have at home and play the stuff you intend on playing once you buy it. There’s no point in ripping out shred metal leads to impress the sales staff and other customers if you’ll be buying the guitar to play rhythm in a ska band. It has to feel and sound right playing your music on it.

Ultimately though, you’re probably just going to buy a guitar that looks really cool. If it makes your heart skip a beat and all day long you’re inspired to pick it up and play it, then it’s still the right choice. You may want to consider the tonal characteristics that it brings to the table though, and set the rest of your rig up to work well with it.