Lugs, the throwoff and the butt plate are all screwed through the shell wall.
Ten solid brass lugs can outweigh the maple shell they are bolted to.
Lighter hardware leaves the shell freer to move.
Hardware rides on the shell.Hardware rides on the shell.
When the shell flexes, everything bolted to it has to move with it.
To the shell, that hardware is extra mass at fixed points around its circumference. How much, and where, changes how the shell behaves.
Fig. 8
Add mass, lower the modes.Add mass, lower the modes.
Mass at the wall lowers every shell mode, just as taking mass out of the wall raises them. It also makes the shell harder to set moving: the same push from the heads moves it less.
What counts is hardware weight compared with shell weight. The lighter the shell, the more its hardware matters, which is why a machined shell and light hardware belong together.
Fig. 8 / Hardware on a 14 × 6.5 maple shellMeasured Lug One weights · simplified ring model
Shell modes, bare vs with hardware
1002005001k
Hardware
335 g
Shell
930 g
Oval mode
78 Hz · -17%
Shell moves
86% as far
Hardware
17.5 g
132 g
Lugs
Shell
Weights are measured Robot parts: Lug One is 17.5 g printed in glass-fiber composite and 118 g machined from solid brass, about as heavy as a lug gets; Throwoff One is 132 g and its butt plate 28 g. Hardware is treated as rigid masses bolted to a thin maple ring. Dashed marks are the bare shell; orange marks are the same shell with hardware. Where a mode shows two marks, the hardware has split it in two. Real lugs also stiffen the wall locally and touch it over an area, which this model leaves out.
Even spacing splits one mode.Even spacing splits one mode.
Evenly spaced lugs look the same to most shell modes, whichever way the mode turns. The exception is the mode whose bulges line up with the lugs: the five-lobed mode on a ten-lug drum, the four-lobed mode on an eight-lug drum.
Turned one way, every bulge carries a lug. Turned the other, every lug sits on a still point. The two versions ring at different pitches. Set the throwoff to zero in Fig. 8, then switch between 8 and 10 lugs and watch the split move.
The throwoff breaks the symmetry.The throwoff breaks the symmetry.
A throwoff on one side and a butt plate on the other are heavier than a lug, and they are not evenly spaced. That lopsided mass splits every shell mode a little, the same way uneven head tension splits head modes in Chapter 05.
It can also cancel a split. On ten lugs, a 132 g Throwoff One sits between two lugs, right where the five-lobed mode was light. It nearly evens that mode out while splitting the others. Mass placement is a tool as much as mass itself.
Same lug, two weights.Same lug, two weights.
Robot Lug One exists in two versions of the same design. Machined from solid brass it weighs 118 g, about as heavy as a lug gets. Printed in glass-fiber-reinforced composite it weighs 17.5 g.
On a 14 × 6.5 maple snare with ten lugs, that is 1,180 g of brass against a 930 g shell, or 175 g of composite. With a Throwoff One (132 g) on both, Fig. 8 has the brass lugs pulling the oval mode down by more than a third and leaving the shell moving about two-thirds as far. With printed lugs the mode drops 17%, and about half of that comes from the throwoff and butt plate.
Neither is wrong. Brass makes a heavier, more held-down drum. Composite leaves the shell free to take part in the sound, which is the drum the rest of this guide describes.
Bibliography
Selected sources.Selected sources.
Primary papers and references used throughout the essay.
