NHT A-20 owner manual Boundary Control, Position Control

BOUNDARY 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.

Quarter Space Quarter/Half Space Half Space Half/Whole Space Whole Space

	1
2	0
	BOUNDARY

	1		1		1
2	0	2	0	2	0
	BOUNDARY		BOUNDARY		BOUNDARY

Fig. 6. Boundary Control Settings Diagram

	1
2	0
	BOUNDARY

POSITION CONTROL:

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.

Listener Distance

	0’	1 M	1.5M	2M	2.5M	3M
A-20					Far-Field
				Mid-field
Monitor
		Near-field

	MF
NF	FF
	POSITION

	MF
NF	FF
	POSITION

	MF
NF	FF
	POSITION

	MF
NF	FF
	POSITION

	MF
NF	FF
	POSITION

Fig. 7. Position Control Settings Diagram