Broom RM 909 reviews Effects Track

1) In film production audio, a recording of the mixdown of all the sound effects for the film ready to be mixed with the dialogue and music.
2) In music recording, one track with a recording of effects to be added to another track of a multitrack recording.

Acoustic Amplifier
The portion of the instrument which makes the vibrating source move more air or move air more efficiently; this makes the sound of the instrument louder. Examples of acoustic amplifiers include:
1) The body of an acoustic guitar,
2) The sounding board of a piano,
3) The bell of a horn and
4) The shell of a drum.

Brooks Cinema XS - 45 reviews Diffraction
The breaking up of a sound wave caused by some type of mechanical interference such as a cabinet edge, grill frame, or other similar object.

Fade
1) A gradual reduction of the level of the audio signal.
2) A gradual change of level from one pre-set level to another.

Brooks QS-70 reviews Action
In guitar playing, action refers to how far the strings sit off of the guitar neck. When strings are close to the neck, it is referred to as "Low Action". When the string sit far above the neck, it is called "High Action". Guitars with low action are easier to play, but make sure they are not too close, or it could causing buzzing.

Impedance
1) A term for the electrical resistance found in a/c circuits. Affects the ability of a cable to transmit low level (e.g. sound) signals over a long distance. Measured in Ohms. Speakers are rated according to power handling capabilities (Watts, W) and impedance (Ohms).
2) The total opposition offered by an electric circuit to the flow of an alternating current of a single frequency. It is a combination of resistance and reactance and is measured in ohms. Remember that a speaker's impedance changes with frequency, it is not a constant value.
3) The opposition to alternating current.

Hypercardioid Pattern
A microphone pick up sensitivity pattern where the least sensitive pick up point is more than 90 degrees but less than 150 degrees off axis (usually 120 degrees).

Baffles
Sound absorbing panels used to prevent sound waves from entering or leaving a certain space