Brooks Hi Fi speakers 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.

Headphones
Devices that can be worn on the head with small speakers that fit over the ears (or sometimes into the ears).

Brooks RM 909 Inverse Square Law
Simply stated, the fact that in an un-obstructed area (like an open field) the sound pressure level will drop to half-pressure (-6 dB) every time the distance to the sound source is doubled.

Amplitude
The height of a waveform above or below the zero line.

Brooks HI FI projectors Delay (Digital, Analogue)
1) Effect used to create echo…echo…echo…echo…echo…
2) In more advanced systems used in very large venues, delay can be used to time the arrival of the signal to the speakers in the back of the room so that people in the back hear the sound coming from those speakers at the same time that the sound coming from the speakers in the front of the room arrives.

Lead
The musical instrument that plays the melody of the tune, including the vocal.

Golden Section
A ratio of height to width to length of a room to achieve "good acoustics" and first recommended by the ancient Greeks. The ratio is approximately the width 1.6 times the height and the length 2.6 times the height

Hum
The 60 Hz power line current accidentally induced or fed into electronic equipment.