Neck wood and it’s effect on tone

Firstly, I have to do a quick rant on questions of tonality.

I have no doubt that, being interested in guitars, you have read any number of forums and articles about the effect of wood on tonality.  A lot of it is good, a lot not.  Just like any other subject.  The worrying thing I find is that it is a lot of opinion dressed up as fact.  A dangerous thing.

Being from a scientific background, I am used to talking about theories.  I therefore, when questioned, will give my opinion based on the theories that both make the most sense to me scientifically, and that can be backed up with empirical evidence.

So, everything you read from me about tone is my opinion.  You are welcome to add your own opinion, and if you can give me sources, all the better.  I am by no means precious about my theories, and am always open to new ideas.

So, back to necks.  Yes, I usually make my necks from mahogany.  Why?  Because everyone else does.  That’s kind of flippant.  What that means is that guitarists are, as a rule, quite traditional, and they don’t want different species necks because they’ve always been mahogany so it must be right, right?

Electric guitars have long been made from a variety of materials.  The best example is Fender.  He decided that, from an engineering perspective, maple would be better than mahogany, because it is harder and stiffer, so it will be more hardwearing and less susceptible to deform under the tension of the strings.

This seems to have led people to believe that the maple neck makes the guitar more trebly.  Well, a strat is certainly more trebly than a Les Paul, but that is probably more to do with single coil pickups on a strat, and a massive slab of mahogany on a Les Paul body.

Let’s look at the science.  A maple neck will be heavier.  Momentum = Mass x Velocity.  In guitar terms, Momentum is sustain and velocity is how hard you pluck the string, so a more massive guitar will have more sustain.

So in conclusion, a heavier guitar (eg. an acoustic with a maple neck rather than a mahogany neck) will have more sustain.  Great.

However, sustain comes at a price.  There is only a certain amount of energy to go around, so if there’s more sustain, so more energy at the tail end of the note, then that energy has to come from somewhere, and it comes from the start of the note.  So, more sustain must equal less attack.

So, which is better?  Neither.  A guitar with lots of sustain will suit a classical guitarist, but a flamenco guitarist wants all attack and no sustain.  Hence flamenco guitars are made from spanish cedar, nice and light, and a classical guitar is made from rosewood, a much heavier wood.

Then we come on to stiffness.  The stiffer the neck, the less likely it will move at all.  So less energy is lost flopping around the neck, and more energy from the string goes into the top.  A completely stiff neck will, in that case have no effect on the tone.  However, having no effect on tone actually IS an effect on the tone.  Because we are used to mahogany necked guitars, which soak up energy from the strings, a maple neck will sound different because it has less effect.  Does that make sense?

So, this is all very complicated and confusing and hasn’t led to any conclusions at all.  Let’s start using some examples.

I once made a guitar with an ebony bridge, fingerboard, back and sides and a maple neck with a sitka top.  That should be a bright guitar, but because I made the back really thin, used an pretty floppy piece of thin spruce, and braced it quite loosely, it ended up having a really nice balance between bass and treble.

So, I guess what I’m saying is, Let’s make the neck out of whatever you want.  I try and add a bit of mass to things like neck block and tailblocks anyway, since I go pretty thin on the top and back.  I need to make up that mass somewhere, or it would be all attack and no sustain, and it’s better to make it up in non-moving parts.

The stiffer the neck wood, the more longevity in the neck.  Lots of people are adding carbon fibre rods to their mahogany necks these days, so you can’t rely on species to give you an idea of neck sound, unless you know what is going on inside.

And yes, you will reduce the mass by making a very thin neck, but all my necks are thin.  As you rightly point out, why should only electric guitarists have comfortable necks?

Regarding headstock shapes.  It’s the same thing, a big headstock will be more massive, so will increase sustain, but flopping that big headstock around uses up energy that would be better used driving the top.

So, in conclusion, make the neck out of whatever you want.  It’ll be fine.  The stiffer the better, I reckon.  That Oregon tonewoods place has got some amazing myrtle neck blanks that I would love to see on a neck.  We could probably get some claro walnut to match the back and sides, or we could laminate different species together to get that stripey look that is popular with electric bassists.

I’ve recently been thinking about a zebrano neck.  That might look cool.  It’s stiff as hell.  Rosewood, ebony, ovangkol, wenge, Limba.  These woods have all been used in electric guitars and have been fantastic.