DRAWING: Click to enlarge.
Balanced & Stable
Main purpose of any neck profile is to provide support for your thumb. When you play, you balance your thumb against the back of the neck, giving leverage to your fingers as they fret the strings.
Trapezoidal Neck Profile™ (US D630,676) is divided into distinct plane surfaces, which provide broad support areas for your thumb. In contrast to a conventional rounded profile, your thumb is highly stable, and leverage improved.
You can prove this to yourself using ordinary objects around you.
Notice how pushing your thumb against a curved surface feels inherently unstable. Muscles of your thumb, forearm, and upper arm are engaged. Your hand constantly adjusts, attempting to maintain balance, because the contact area is very small.
Repeating the experiment by pushing against a flat plane surface demonstrates your thumb feels much more stable, by comparison. Contact area is enlarged, and additional surface engaged to support your thumb, giving you greater control.
Note how your hand relaxes.
TNP™ relieves tension in your muscles and tendons. Reducing stress can help prevent or heal repetitive stress injury (RSI). When you are relaxed, your movements become faster, more fluid, and precise.
For necks that will be played with pinch grip, palm grip, or thumb-over grip, a P1 surface with a constant width is suggested. For most musicians, choose a width that will comfortably fit between the index finger and thumb joint, with the P1 surface in contact only with the skin of the hand (photos below).
P1 to P2 corner intersections can be rounded, as desired.
Necks played primarily with classical grip can use an extended width P1 surface, maximizing thumb contact area. Width of P2 surfaces decrease proportionately.
Depth of the neck is a matter of personal preference. Conventional truss rod functions just as it would in a rounded neck profile. Due to the geometry of the TNP™ the neck is actually more stiff than a rounded profile of identical depth.
Photos illustrate how the TNP™ interacts with the hand. In this example, Orchid 4-string bass built by luther Rick Toone serves as our model.
Compare the photos below with the ergonomics section of Intersecting Plane Neck Profile™.
PHOTO: Classical grip position. Thumb balanced and stable against P1 surface.
PHOTO: Pinch grip position. P2 surfaces support both the thumb and the index finger, including joint. Wrist is aligned, relaxed. Hand is not in contact with P1 surface.
PHOTO: Palm grip or thumb-over position. P1 surface falls entirely within the fleshy web in the palm of the hand, between index finger and thumb. Corners where P1 and P2 intersect are never in contact with bone. A constant width P1 surface along the length of the neck will maintain this ergonomic comfort.