User's Manual

BOUNDARY CONTROL:

POSITION CONTROL:

Reflective boundaries, such as floors, walls, even table tops, reinforce a speaker’s low frequency output. Conversely,

placing speakers out into a room decreases bass response. The highest low frequency output is with the BOUNDARY

control in the “0” position, which assumes no significant boundary reinforcement is present. Each control step

attenuates low frequencies by 1.5 dB (at 50 Hz), with rapidly decreasing effect above 300 Hz. Refer to the diagram

in Fig. 6 for information on setting the control appropriately.

Near-field monitoring reduces the effect of room acoustics on the signal, and provides greater sonic detail. Mid- and

far-field listening reveals aspects of recorded ambience and is more representative of end use. However, a speaker’s

upper frequency power response changes with distance, due to room influences and air absorption. The A-20 may be

adjusted for flat response at various listening distances. The maximum high frequency output is obtained with the

control in the “FF” (far-field) position. Each control step attenuates 20 kHz by an additional .75 dB (towards

the near-field position) with no effect on frequencies below 3 kHz. See Fig. 7 for appropriate POSITION control

settings based on listening distances.

BOUNDARY

Quarter Space

Quarter/Half Space

Half Space

Half/Whole Space

Whole Space

Fig. 6. Boundary Control Settings Diagram

0’

1.5M

2.5M

Near-field

Mid-field

Listener Distance

A-20

Monitor

Far-Field

POSITION

Fig. 7. Position Control Settings Diagram