When purchasing vintage speakers and other sound equipment, here are some of the most important acronyms that you need to pay attention to.

DAC (D/A) refers to a digital to analog converter. This is a component or circuit that is intended to derive or convert an analog signal from a digital one.


DSP stand for Digital Signal Processor. The process of optimizing the frequency response of a loudspeaker system entails at least some form of an electronic equalizer. That could be a graphic equalizer, or preferably a parametric equalizer. A digital signal processor is essentially a specialized computer, which means that it can be password protected to minimize unauthorized access.


EQ refers to the equalizer. On a console, that would usually be the equalizer controls on every input or output channel.


Fb, which is measured in Hz, stands for the resonant frequency of the air in a port and the stiffness of the air in a ported system. This is also referred to as the tuning frequency of a vented enclosure.

PA or a public address system refers to an electronic system which includes microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound source or recorded sound or music.


RTA is the abbreviation of a Real Time Analyzer, which is a typical audio measurement device that displays the sound energy found in discrete frequency bands. A simple Sound Level Meter just demonstrates shows the overall sound level being measured, while an RTA demonstrates the contribution of individual frequency bands that compose that overall sound level.


S/N stand for Signal to Noise Ratio. This is the ratio of the desired signal level to the level of unwanted noise (which is measured in decibels).

stands for Tip-Ring-Sleeve. This is used to describe 1/4″ (or 1/8″) balanced connectors. A TRS plug is located at the end of most headphone cords. It appears as a standard 1/4″ plug with an extra “ring” on its shaft. TRS connectors are used wherever you need to have two conductors plus a ground (shield) in one plug.