Containing, producing, arising from, actuated by, related to, or
associated with sound.
Acoustic is used to modify terms that designate an object, or
physical characteristics, associated with sound waves; acoustical is
used when the term being qualified does not designate explicitly
something that has such properties, dimensions, or physical
characteristics.
The following terms are examples of those modified by acoustic;
impedance, intertance, load (radiation field), output (sound power),
energy, wave, medium, signal, conduit, absorptivity, transducer.
The following examples do not have the requisite physical
characteristics and therefore take acoustical; society, method,
engineer, school, glossary, symbol, problem, measurement, point of view,
device.
As illustrated, the generic term is usually modified by acoustical,
whereas the specific technical term calls for acoustic.
