Using a sanding board to keep straight lines...
Using a scraper to refine neck shape
Match these two areas acoustically : the side tap of the neck wood at fingerboard joint, while the side tap all along the length of the fingerboard ,(and all over the side surfaces of the fingerboard) will be an even 242 HZ .When alternatively tapped, they will sound in harmony.
Tap these two places and compare...
Material is removed here to raise the neck side tap tone at the glue joint.
Material is removed here to lower neck side tap tone...
Set the neck section thickness first, before fine tuning...
..Ebony wood fingerboard, top surface at 227 1/2 HZ
...This is the sound specturm from a tap on one plate of a recent violin, and will serve as an example of what a tap tone is composed of and what we are to listen for:
...On the left is sound level in Db; on the bottom you see the frequencies generated by a tap in the center of the top plate of my Opus #22 violin. The first prominent sound peak is the 'fundamental tap tone' that we are to listening for. However, our wonderfully designed ears (brain, nerves, etc.) hear all these generated sound frequencies at once. The highest pitches (in this case 4,000 hertz, vibrations per second) is the easiest for your ears to hear, as our hearing is more sensitive to high frequency sound. The 'fundamental' tap tone is the tap tone frequency that we want to hear and compare.
...Given the DB scale for loudness, an increase of 10 DB is twice the sound loudness (unless I misunderstand).
Modified 3/2021
Page AA_25/_63
...Cross Section of the neck with the fingerboard down:
198 HZ
242 HZ
..Transition 198 to 242 HZ..
242 HZ
(227 1/2)HZ
