[I]CHAPTER 13
Making (Bass) Waves—Below the Transition Frequency
218
(a) In the beginning, some number of full-range loudspeakers are located as required by the playback format (2, 5, 6, or 7 channels):
listener hears unpredictable and different bass quantity and qualityfrom each channel.
bass shared among all channels is unpredictable and differentfrom that in the individual channels.
other listeners in the room hear bass that is different from eachother and from that at the sweet spot.
equalization of bass gives unpredictable results because basstreatment in recordings is not standardized: some is steered, someis shared among the channels
(b) Bass management + one or more subwoofers located arbitrarily or experimentally:
each listener hears the same bass quality from each channel, andthe same bass quality when it is shared among the channels.
the quantity and quality of the bass may differ from the program.
listeners in each seat in the room hear bass that is different fromthe others and from that at the sweet spot.(c) As (b) above + equalization at the sweet spot (dark seat):
as above, except that the quantity and quality of the bass issubstantially predictable for the listener in the sweet spot—and
only
for that listener.(d) As (b) above + equalization employing measurements atseveral locations in the listening area:
because the physics of the room are unchanged, the seat-to-seatdifferences remain.equalization in the signal path to the subwoofer involves a decisionabout which seats are most important so that the compromisesolution can be configured to bring the greatest pleasure to themaximum number of listeners. No listener may receive the fullyoptimized bass delivered to the sweet spot in solution
(c).(e) Mode manipulation in simple rectangular rooms.Bass management + multiple subwoofers + equalization:
using multiple subwoofers in the appropriate locations, the soundfield in the room is manipulated so as to reduce seat-to-seatvariations within a designated area.
all listeners
within the specified area hear similar bass fromeach channel, and the same bass when it is shared among thechannels. Equalization is required for good sound.
.....
Making (Bass) Waves—Below the Transition Frequency
218
(a) In the beginning, some number of full-range loudspeakers are located as required by the playback format (2, 5, 6, or 7 channels):
listener hears unpredictable and different bass quantity and qualityfrom each channel.
bass shared among all channels is unpredictable and differentfrom that in the individual channels.
other listeners in the room hear bass that is different from eachother and from that at the sweet spot.
equalization of bass gives unpredictable results because basstreatment in recordings is not standardized: some is steered, someis shared among the channels
(b) Bass management + one or more subwoofers located arbitrarily or experimentally:
each listener hears the same bass quality from each channel, andthe same bass quality when it is shared among the channels.
the quantity and quality of the bass may differ from the program.
listeners in each seat in the room hear bass that is different fromthe others and from that at the sweet spot.(c) As (b) above + equalization at the sweet spot (dark seat):
as above, except that the quantity and quality of the bass issubstantially predictable for the listener in the sweet spot—and
only
for that listener.(d) As (b) above + equalization employing measurements atseveral locations in the listening area:
because the physics of the room are unchanged, the seat-to-seatdifferences remain.equalization in the signal path to the subwoofer involves a decisionabout which seats are most important so that the compromisesolution can be configured to bring the greatest pleasure to themaximum number of listeners. No listener may receive the fullyoptimized bass delivered to the sweet spot in solution
(c).(e) Mode manipulation in simple rectangular rooms.Bass management + multiple subwoofers + equalization:
using multiple subwoofers in the appropriate locations, the soundfield in the room is manipulated so as to reduce seat-to-seatvariations within a designated area.
all listeners
within the specified area hear similar bass fromeach channel, and the same bass when it is shared among thechannels. Equalization is required for good sound.
.....
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