Here I will describe the process of designing and building a 4-string bass guitar as it unfolds.
Project 2 Build
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Project 2 Design
The neck was purchased from Carvin. To make an accurate neck, I would need to spend quite a lot on tools. Supposedly, Carvin's machines make
their fretboards accurate to less than 0.001". However, I've heard of their necks having a high fret here and there. The most accurately shaped fingerboard with a high fret is still a poor-playing neck. Hopefully this neck doesn't have any problems. The fretboard is ebony with mother-of-pearl
block inlays. The headstock has a flamed maple veneer, and there is extra length on the neck
so that it can be used for a neck-through bass. Carvin reinforces their necks with two
graphite rods. My preference is for a thicker neck with no graphite rods; more wood. Neck-through basses tend to have more stable necks and greater sustain. They are also generally more resonant and more sensitive to the touch; require better technique to play cleanly. Neck-through basses are usually constructed so that access to the upper frets is unhampered by a bulky neck 'heel'; as is common with bolt-on basses. Bolt-on basses tend to sound punchier/warmer, and allow for neck replacement. A compromise between the two designs is a set neck. Set necks are essentially the bolt-on design fastened to the body with glue instead of bolts. The result is generally a mix of the properties of neck-through and bolt-on construction.
This picture shows the neck and some bookmatched 1" thick flamed maple that I plan on using for the
top. Since each piece of maple is 1" thick, and the total thickness of the bass will be about
2", I have to find someone with a saw large enough to cut one of these boards to make it half as
thick (this is called resawing). Therefore, the maple top will only be 1/2" thick, and the rest of the body will be either
mahogany, koa, or some other wood.
Making a bass is like making a sandwich, there are some things
in the sandwich that dominate its taste, but everything you put in it will affect its flavor. With
a bass, some things will dominate its tone, but everything that makes up the bass will affect it. The art that goes into making a bass is knowing how every element affects its tone, playability, and feel, and creating a desirable mix of these outcomes in an aesthetic way. Everything from body shape to the type of nut and frets, to the size and shape of the
headstock affects tone, playability, and feel. Take a wide, long, and thin board of wood and tap on it. Compare the 'tap tone' to the sound a thicker and more compact piece of the same species (preferably the same tree) makes. The first tone will be of a lower pitch, while the second will be higher. They will resonate differently due to their different properties; in this case the dominant property is shape, having largely controlled for the others. Ceteris paribus, you would expect a thick and compact guitar to produce less lower frequency response than a thin and large one. The extent to which shape will affect tone has to be balanced with aesthetic and ergonomic decisions. Depending on the design 'mandate', you can often find more than one way to achieve your chosen mix of outcomes.
Putting size and shape aside, everything from how and where the tree grew, to how the wood was processed, treated, and stored affects guitar tone, resonance, and sustain. An ash tree that grew in a swamp (Swamp Ash from the southern US) will sound very different from an ash tree that grew in a forest (Northern Ash). The fibers of Swamp Ash are less compactly structured (partly due to its growth climate) than Northern Ash fibers. The lighter Swamp Ash is known for providing exceptional dynamic response and strong bottom end, while the heavier Northern Ash can be flat and harsh sounding. A popular challenge among bass builders is to replicate the tone and feel of early Fender Precision and Jazz basses. Nearly all of them claim their efforts are unsuccessful and put forth a myriad of possible explanations. My favorite guesses are: the wood used half a century ago is different from what's available today (trees grew slower, weren't farmed), the nitrocellulose lacquer finish cracks over time and allows the wood to breathe.
A guitar's finish, hardware, electronic components, and strings can all have a dramatic effect on tone. I haven't talked about amplifiers, speakers, and signal processors, which can all make or break great tone. I've also neglected the most important link in the 'tone chain', the player. A player's individual way of touching the strings determines how the instrument will respond. Everything from the size of the hands and finger pads, to the length of the fingernails, to the pressure and angle with which the strings are struck and fretted and where along their length they are struck and fretted affects tone.
The ebony fingerboard combined with the maple neck
will give a very traditional tone. Maple produces a bright, sweet tone, while ebony is heard as transparent
high-end. The shape and size of the headstock will be determined after the rest of the bass is
designed. It will be used to help balance the bass in playing position. This balancing will depend on the mass
of the bridge, and where the straplocks are placed (which affects how and at what angles the bass hangs on the player). For a finish, I am considering a shellac/varnish
combination, and a tung oil/varnish or urethane combination. I would like a hint of 'growl' heard in Warwick basses. An oil finish
deadens high frequency response (an oily species of wood does the same), resulting in a compressed organic tone.
To get an idea of how wood and neck-type affect the tone of bass guitars, check out the Warrior Instruments page
titled "Listening Room":
These pictures show the fretboard and nut masked off in preparation for construction. The blue tape is safe-release tape; it won't leave a sticky residue or pull anything off
with it (like little splinters of wood). You can also see a pencil line laying out the position of a jazz pickup. I think I'm going to put
two jazz pickups in this bass, haven't decided what kind.
I thought about what I like about the G&L L2000 that I play, and what could
be improved upon.
I like how versatile the G&L L2000's electronics are. With
the front pickup soloed, it gives a very convincing p-bass sound. With both pickups in
series, it gives a very modern EMG-esque sound. And with the bridge position soloed it
sounds very much like a jazz bass. I also like how the instrument balances on the strap
and the position of the upper horn in relation to the frets (which determines how close first
position is when standing and playing).
I decided to go with Dimarzio Ultra Jazz pickups and the Aguilar OBP-3 preamp. These pickups are made
with both alnico and ceramic magnets, and should offer a great modern take on the classic. The Aguilar OBP-3 provides boost and cut in bass,
treble, and two mid-centered frequencies, and is well regarded for thickening the tone, fleshing it out, completing the picture, without making it muddy.
My main complaint about the G&L is its heavy weight. It also suffers from unbalanced
string-to-string response/sustain, some deadspots, and noisy electronics (unshielded cavity).
I plan on making my bass as thin as possible. It will be just as thick as needed for installation
of battery boxes, while leaving 3/16" extra thickness. This combined with the use of Honduras
mahogany should assist in weight management. The Dimarzio pickups are passive pickups, and are not
specifically made to be used with active electronics like some Bartolini, Seymour Duncan, and EMG pickups are. Therefore,
they should be noisier with the Aguilar preamp than a completely active system. I contacted Dimarzio and
Aguilar, and they both insisted that noise should not be a problem.