I remember I first heard about neck-through's sounding better than bolt-on's somewhere back in the late 80's. I can imagine how this sorted out. It probably happened that someone compared the tone of one of the beautiful neck-through instruments of those times (Alembic, Ken Smith, Tobias, etc.) to a bolt-on Precision or Jazz bass and noted some obvious difference in tone.

Of course these differences were not all due to the construction of the neck joint itself, but also to many other characteristics those instruments featured, of which the common goal was just one: improving the strings vibration.
Bolt on vs neck through
A Frudua Slave Pentabass through-neck bass.

In fact, if you compare an old Ken Smith bass to a standard Jazz bass, you will note that the neck construction (laminated on the first, and one block of wood on the second) is not the only difference. You will also notice that the Ken Smith sports some very hard woods, a high mass bridge, reinforced neck and reinforcements over and under the headstock, a fatter neck to body joint, etc.

The sum of all those features results in stiffening the neck, raising the resonance pitch of the whole instrument over that of the strings, and consequently delivering the purest and most even string vibration with increased sustain and elimination of "dead spots".

This is where neck-through construction's fame comes from.

What prevented a wider diffusion of neck-through instruments was the high construction and manufacturing costs of this solution and the fact that NT is more used on basses than on guitars due to both the fact that this kind of approach is more valuable on instruments with a lower pitched resonance, and also to the fact that guitars are in some ways more difficult to build due to the presence of more hardware (tremolo cavities, etc).

Bolt-on necks are normally one piece of maple fixed to the body with 4 or more screws which are often bolted directly into the wood, and more rarely into countersunk threads.

These bolts often lay on a screw plate and sometimes also on dedicated bushings in the case that a contoured neck heel is present. The body is here separated from the neck and is normally built in a light or medium-light wood, like basswood, alder, and sometimes birch or poplar. The neck is most of the times made from a single piece of hard rock maple.

The typical bolt on neck joint (rear view of Tuscany '54 model).

Both neck-through and bolt-on methods offer certain advantages and we should consider them all.

One of the advantages of bolt-on is that you can always replace the neck if it breaks or becomes defective, and this provides more options to repair, adjust and modify.

Actually we feel more comfortable experimenting with bolt-on's because we know, in case we break them, we will not have to throw the whole instrument away.

Tone wise, compared to other solutions, bolt-on necks allow us to build the body from a single piece of wood, which sometimes may be a good way to achieve a full-bodied tone.

In fact, if the two parts are built with selected woods and carefully matched, then we will obtain from a bolt-on, a wonderful instrument sporting a superior volume and fine harmonic content, sometimes even better than that of any neck-through design: this unfortunately happens only randomly though.

Wood selection plays a very important role in electric guitar construction and tone.

Indeed, when neck and body wood for bolt-on's are matched casually, the neck-thorough solution will give much better results. Through necks also permits a contoured neck heel which allows better access to the highest positions on the fretboard. This does not have to be too contoured though, otherwise it will weaken the neck joint and have a bad influence on the instruments stiffness, sustain and tone.

Some manufacturers have recently tried to include, for bolt-on's, this easier access to the last frets by "contouring" the neck heel with interesting results (see photo below).

Contoured neck heel on Frudua GFT-SHB and Frudua GFJ bass.


Most probably, the most amazing sounding instrument out there is a bolt-on guitar or bass, but still, the neck-through option offers an average high quality that is very appealing to some of us. All strongly depends on how woods have been cut and matched, especially for bolt-on's, and this teaches us the importance of selecting wood.

Neck-through solutions will deliver a longer sustain, a more defined attack and a higher note definition, especially on the fundamental harmonics, which is good for the low B for example. In brief, a less personal but more HI-FI tone, with a more even and standard quality.

Bolt-on solutions deliver a "wilder" tone, where harmonics and volume are accentuated and therefore associated to a more "vintage" feel.

This is also psychological. The reduced resonance of the fundamental harmonic, compared to neck-through constructions, forces the brain to "reconstruct" the fundamental, extracting it from the partials harmonics (*).

For all the above reasons the neck-through basses sound is average-good, while among the bolt-on's we will find some ordinary instruments, as well as some exceptional ones.

Glueing a through-neck.

(*)This is exactly what happens with the low B of multi-string basses where their fundamental resonates at 30Hz and they're often played through enclosures and amps that are rarely capable of reproducing frequencies below 70Hz.

The brain artificially recreates the low B fundamental starting from the upper partials, and so we still have the illusion of hearing it.

The same happens with the telephone, which can't reproduce the fundamental of the human voice, but we still have the impression of hearing the familiar and normal vocal quality of the person we are talking to, due to the fact that the brain reproduces missing frequencies from the harmonics it has available.

© 2018 Galeazzo Frudua. All rights reserved

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