Several definitions apply to us.
- In electronic or mechanical devices, a mode is a state of operation where a defined set of actions can be accomplished. In an effects processor, for example, a mode may be the editing mode. In this mode you can get inside the parameters and alter the way the device processes sound. Many electronic devices have keys or buttons that can perform different operations depending upon which mode they are in.
- In music theory modes are fixed patterns or arrangements of the diatonic tones of an octave. Also a patterned arrangement of a scale such as Major, Minor, Dorian, Locrian (sometimes jokingly referred to as the Devil’s mode), etc.
- In acoustics, a mode is one of the possible resonant frequencies of a vibrational system. The geometry of a room, for example, will cause it to have a number of modes. These result in standing waves at those frequencies, which will have the effect of reinforcing or attenuating some frequencies in that space. Modes can be predicted mathematically so one of the practices of acousticians is to construct spaces so room modes get distributed so as not to reinforce or attenuate any one section of the frequency spectrum.