Sony G90 User Manual
Page 30
speaker systems. For example, if you have five
small loudspeakers and a subwoofer, you tell
the controller to filter bass from each of the
five channels, and to direct it, in sum, to the
subwoofer. When watching a Dolby Digital or
DTS movie, the bass from the LCR and sur-
round channels is mixed with the Low Fre-
quency Effects channel to drive the subwoofer.
The bass management in most controllers lets you
direct the full frequency range to the left and right channels
(including the LFE channel), but filter bass from the center
and surround channels.
A feature in the most advanced controllers is the ability
to specify the crossover frequency and slopes between the
subwoofer and main speakers. The crossover is implement-
ed in the digital domain with DSP. Splitting the frequency
spectrum into bass and treble in the controller is a vastly
better approach than subject-
ing the analog audio signal to
the capacitors, resistors, and
inductors found in the cross-
overs built into subwoofers.
Other controllers let you
specify the crossover frequency (40 Hz, 80 Hz, 120 Hz, for
example), but not the slope or phase characteristics. The
greater the flexibility in this function, the greater the likeli-
hood that you can achieve the best results with your speak-
ers and room.
Keeping low bass out of smaller loudspeak-
ers confers large advantages in the speaker’s
power handling, dynamic range, midrange clari-
ty, and sense of ease. When the woofer doesn’t
have to move back and forth a long distance try-
ing to reproduce low bass, the midrange sounds
cleaner and the speaker can reproduce louder
peaks without distortion.
High-Resolution Digital Audio
Decoding
Many controllers today feature the ability to accept digital
input signals with a sampling frequency of 96 kHz and word
lengths of up to 24 bits. This allows them to decode high-res-
olution digital audio output from a DVD player that can
deliver 24/96 digital signals (the Pioneer DV-09 is an exam-
ple). The selection of 24/96 discs is slim, and until a digital
interface with a copy-protec-
tion system is in place, don’t
expect many DVD players to
provide access to the 24/96
bitstream.
A more useful feature for
taking advantage of the high-resolution multi-channel for-
mats about to come on the market (DVD-Audio and Super
Audio CD – SACD) is a six-channel analog input on the con-
troller. Until the digital-interface issue is resolved (which
may take a long time because it is inextricably linked to the
…the controller represents
a radical new path to
the future…