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Drum Science
This category relates to the science of drums

Sachs Hornbostel System of Instrument Classification


The Sachs-Hornbostel System was created in 1914 to categorise musical instruments into logical family groupings based on the nature of the initial vibrating body.  This is different from the orchestral system of brass, woodwind etc etc

4 major groupings were arrived at initially and remain,

  • Idiophones: instruments that are constructed of solid material that vibrates by virtue of their own inherent rigidity such as claves or marimba bars.
  • Membranophones: instruments that rely on a stretched membrane to trigger the sound, includes all drums.
  • Chordophones; instruments that rely on a stretched string, such as a guitar or piano; and
  • Aerophones: instruments that rely on air such as saxophones or didjeridus

Since that time, a fifth grouping has been added, that of Electrophones where the initial vibration is the pulses of electricity in a wire.  A further grouping of Hydrophones where the vibrator is water based is also under consideration.

Drumshell - Shell Sizes

Drumshell Sizes

The size of a shell is measured in diameter by depth. A 14 inch snare, with a depth of 5 and 1/2 inches would be notated as: 14x5-1/2 (5.5). A 12 inch tom that is 10 inches deep would be: 12x10. (Some companies reverse this notation, but we won't raise a fuss.)

Shell Thickness

thin.gif (3495 bytes)Shell Thickness

In a nutshell, the thicker the shell, the more higher it will sound. The thinner the shell, the lower it will sound.
Don't get caught up in plies. You can't always judge a shell's thickness by how many plies it has. Some companies cut their plies thinner or thicker than others. The density of the wood also determines how thin a ply can be cut. Lauan plies will be much thicker than Birch, for example, because Birch is stronger and can be cut thinner. Or one company's 9 ply shell could be thinner than another company's 6 ply shell. There are many variables.

Shells - Maple, Birch and Lauan

Maple, Birch, and Lauan.

Most drum shells are made of one of these woods, so we will compare them. Lauan is the softest of these woods and it is also the least attractive, which contributes to it being the least expensive of the three. For this reason it is often used in low end, budget drums. Because it is relatively unattractive, most lauan drums will be covered in a plastic. This also makes them less expensive to make, because a plastic wrap far less labor intensive than a spray finish.

Shell Construction - Why Wood

Why are drum shells made of wood?


Got me? No really, there isn't a special reason, other than wood sounds nice. As in other musical instruments, wood just has the kind of characteristics that lend it to producing a pleasant tone. Other materials are used for making musical instruments; metal, bamboo, plastic. But for certain instruments, wood is just the material of choice. I mean, we've had a several hundred years to figure it out, right?

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