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Hello all togeather!
Do you have any target for neck weight? Does it matter for tonal quality?
Thanks to anyone here in the forum for sharing your knowledge with us! I have learnt so much from you during the last year!

I don't usually worry about neck weight until it starts to change the balance of the guitar. If the body is ultra light, you dont want a heavy neck, itll keep tipping in the players lap.

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Technically yes, but it’s pretty far down on the list of things that matter. The only time I concern myself about it is as Marcus suggested, when I have a very very light weight body…

Yes but why and how it matters is subjective and not something a builder should worry about unless.... unless they are going to create an undesirable tendency in the instrument such as neck diving... You do not want to take your hands off the instrument in your lap and have it dive toward the neck.

Tonally many players will claim it matters but it's subjective. They cite putting a capo on the end of the head stock and hearing a tonal difference. I just think they have better pot than I do....

As for if anyone here will know definitively and be able to prove it with empirical data if the neck weight has this or that impact on tone.... nope.

This is also related to the ole debate of dovetail joint vs. bolt-on neck. Since we are considering how the neck is "coupled" to the body this was a hill that many were willing to die on some decades back with the advent of Taylor Guitars. What was the result? Lots of folks died on that hill and we have their guitars now and no one was ever able to prove one way or the other. It's subjective again and so it much of this stuff.

And it really really matters for ukes. They are played by pressing the body of the instrument against the players body with the forearm. If the player is a good one and moving up and down the neck the instrument shouldn’t have the be held tightly to prevent tipping.

The is a factor of the neck wood but also the tuners. I had some feedback from players about putting guitar tuners on ukes. I now use only lightweight tuners.


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Hesh wrote:
"As for if anyone here will know definitively and be able to prove it with empirical data if the neck weight has this or that impact on tone.... nope."

Neck weight per se, no, but...

The lowest pitched structural resonance of the guitar is the 'first corpus' mode, where the entire instrument vibrates like a xylophone bar in it's fundamental mode. There are two stationary 'node' lines, one near the nut or first fret, and the other across the body around the bridge area. If the guitar supported by pinching it at the first fret and allowed to hang freely you can tap on the back of the headstock with the ball of your finger and hear this mode. On most steel string guitars it comes in at around C~65 Hz, but on some Classicals it can be much higher in pitch. If the guitar is supported on a bench top at those nodes and tapped the head and tail will be moving 'up' as the neck block is moving 'down'. The neck bends a lot in this mode, so it's often referred to as the 'neck mode', even though it involves the whole guitar, and I'll use that term here.

If this 'neck' mode pitch is high enough to be close to the 'main air' resonance the two can couple. As the neck block moves 'down' and the ends of the head and tail move 'up' it puts pressure along the length of the top. Since most tops are more oe less domed, either by design or just string tension, this lengthwise pressure causes the top to 'puff up', and suck a little air in at the hole. As the movement reverses the air is pumped out (if the top is 'dished' I guess it would just work backward). This is what the guitar does naturally at the 'main air' pitch, so the bending of the 'neck mode' works with it to pump air in and out of the hole if the two are aligned closely. Air pressure changes in the box can also drive the 'neck' mode when the pitches agree.

When this happens the 'neck mode' can actually steal energy from the 'air' resonance and store it, like a flywheel. This can be observed in an 'impulse spectrum' of the guitar as a 'notch' in the output. The 'neck' mode can also work to pump air in and out of the hole. When the two resonances are closely aligned the 'main air' output peak will be split into two peaks, lower in height than the usual single peak of an isolated 'air' resonance, but covering a wider frequency range.

A close alignment of the 'main air' resonance with a played note (often near G on the low E string) is the cause of the most common guitar 'wolf' note, as the top and air extract energy from the string to produce a note that is twice as powerful for half as long. We don't usually notice the added power, but the lack of sustain is an issue.

When the 'neck' and 'air' modes align closely the reduced peak height means that the guitar is not able to 'suck' the energy out of the string as fast: instead of one very strong, short note you get two or three that are firm, with normal sustain. When the couple is particularly strong the low end sound can be 'darker' or 'warmer'. The 'feel' of the guitar is also affected: it's more 'live' in that range.

Neck weight per se is less of a factor in this than it's stiffness. Headstock and tuner weight is a major factor. Classicals generally have 12-fret necks, and are usually wider and deeper than steel string necks, so the Classical neck is stiffer. A Flamenco guitar, with light peg tuners, is more likely to have the higher 'neck' mode pitch. High-end Classical makers often seem to end up with well-matched 'neck' modes. It can be most easily controlled by carving the neck with pronounced taper: 3-4 mm deeper at the body end than at the first fret. Some fairly recent experiments with bolt-ons suggest that too much hardware in the heel and end block can drop the 'neck' pitch. At such low pitches the frequency match has to be quite close for this to work, and a couple of Hz makes a difference.

So, again, neck weight per se is less of an issue than how and where that weight is, and tuner weight is a bigger factor. But it can matter.

On banjos (OK, I know they're banjos), I always think of matching the weight/density/stiffness of the neck to the rim (body) as impedance matching. Getting the "impedance" of the neck to match that of the rim. My approach has always been completely empirical--I admire you guys who do all of this scientifically, but this is just a banjo, and I trust my ears. I adjust this "impedance match" by starting out with a pretty beefy heel and then reducing its mass until the sound gets to where I want it to be. A lot easier to do on a banjo than it would be on a guitar. But it makes a big difference in sound in the final product. There's a definite sweet spot where everything seems to come together. I guess it's akin to tap tuning a plate.

I'm very fond of rosewood or other heavier resinous woods for necks, even on guitars. I think that the neck wood has a big impact on the overall tone of the finished instrument, and I would bet that is at least in part due to factors that Alan mentioned. But no matter the wood or whatever the underlying physics of the various modes are, there is a sweet spot between the mass/stiffness/weight of the neck and the particular body I'm working with.

Dave