Filter
Top Products
ES DVD Players 2005, Version 4.0 Page 29
Speaker Time Alignment
For optimum playback, the mastering engineers who create CDs need to
anticipate the speaker configuration over which the music will be reproduced. In
stereo, that configuration is simple: two identical speakers ideally set an equal
distance from the listener. In a multi-channel sound, the ideal is slightly more
complex. Multi-channel Super Audio CD is designed to conform to an
international standard, called ITU-R. This envisions that the listener sits in the
exact center of a circle of five identical speakers, with each speaker occupying a
specified position in the circle. (For the Low Frequency Effects or LFE channel,
the subwoofer can be flexibly placed outside the circle.)
The ITU-R circle makes a great reference for studio engineers. But few
home environments can accommodate exactly this setup. Even if you did have
five identical speakers all the way around, the rectangular shape of most rooms
would make it difficult to place all five speakers at equal distance from the
listening position.
Reference
30°
110°
Center
Left
Ri
g
ht
Left surround
Right surround
LF
Mastering for Super Audio CD multi-channel sound assumes that
speakers will be placed according to the international ITU-R standard.
To resolve the problem, Sony provides a special Digital Signal Processor
(DSP) that adjusts the arrival time of each channel with delay in 900-
microsecond increments. Because most people can't make the mental leap from
microseconds to speaker distance, Sony calibrates the delay as distance, in 30-
cm (1-foot) increments. Each 900 microseconds of delay "moves" a speaker
back 30 cm (1 foot). In this way, Speaker Time Alignment adjusts the "virtual
position" of each speaker, enabling you to synchronize the arrival time of sound
for all five speakers. You can even change the perceived distance of the
subwoofer in relation to the other speakers. With Speaker Time Alignment, you'll
experience multi-channel sound as it was meant to be heard. You'll get the effect
of correct speaker placement, even if your actual placement is far less than
correct!