Brooks RM 909 Balanced input/output

A "balanced" connection is one that has three wires to move the signal. One is a ground, and the other two (called conductors) carry signals of equal value. This is why they are called balanced. Low Z cables and connections are the most common example.

Folded Horn
A speaker design where the speaker points back into the cabinet and bounces around finally coming out large ports in the front. It is intended to maximize low frequencies in a relatively small cabinet.

Brooks RM 909 reviews Balance Control
A control on a stereo amplifier that when moved clockwise will make the right channel louder (and the left channel softer) and will do the reverse when moved counter-clockwise.

Decibel (dB)
1) Relative measurement for the volume (loudness) of sound. Also used to measure the difference between two voltages, or two currents. See Zero dB.
2) A numerical expression of the relative loudness of a sound. The difference in decibels between two
sounds is ten times the common logarithm of the ratio of their power levels.

Brooks Hi Fi speakers Flutter
1) High-frequency variations in pitch of a recorded waveform due to fast speed variations in a recorder or playback machine.
2) Originally, and more formally, any variations (fast or slow) in pitch of a recorded tone due to speed fluctuations in a recorder or playback unit.

A/D
An abbreviation of Analog to Digital Conversion (the conversion of a quantity that has continuous changes into numbers that approximate those changes), or Analog to Digital Converter.

Early Reflections
The first echoes in a room, caused by the sound from the sound source reflecting off one surface before reaching the listener.

Line Input
An input designed to take a line level signal.