VANTAS DPA-P87 Owner's Manual - Surround Modes
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The DPA-P87 employs a Dolby Digital (AC-3) decoder, providing playback for the latest generation of
multi-channel digital audio sources. Dolby Digital provides five full range channels [main left, center, main
right, surround left and surround right] and a sixth bass-only effect channel, commonly referred to as LFE
(low frequency effect). This low bass effect is independent of any other channel. Since this channel only uses
a fraction of the available bandwidth, it is referred to as 0.1, hence the term 5.1 channels of audio. Unlike
Dolby Pro Logic with its mono surrounds, Dolby Digital features stereo (split) surrounds. The surrounds offer
the same full range fidelity as the three front speakers.
Expanding the realism and heightening the home theater experience, Dolby Digital provides an increased
dynamic range with precise sound localization and improved sound quality compared to previous Dolby
Surround. There is an abundant library of DVD and Laserdisc titles available in Dolby Digital. Dolby Digital is
also applied to DSS, CATV and HDTV sources. The continued release of Dolby Digital theatrical releases
ensures a constant supply of Dolby Digital-encoded software.
The DPA-P87 will also decode MPEG sources, which is an approved compression scheme for audio formats
on DVD in PAL territories (Europe). It is also available on satellite broadcasts and computer multimedia.
Vantas has included this format on the DPA-P87 to ensure it is compatible with current and future digital
formats.
The DPA-P87 also employs a digital Pro Logic decoder. Pro Logic can be used to create a surround effect on
2-channel sources. Dolby Surround digital sources can be found on CDs, Laserdiscs, etc. When a digital 2-ch
source (PCM, MPEG or 2-ch Dolby Digital) is played on the DPA-P87, the Pro Logic processor decodes the
signal and properly distributes the surround-sound effects.
The Dolby Pro Logic decoder employed in the DPA-P87 is 100% digital processing and reduces crosstalk
between channels and provides accurate positioning of the sound in the listening environment. The regular
Pro Logic mode requires a dedicated center channel speaker. The Pro Logic (phantom center) mode is used
when there is no center channel speaker. In this mode the center information is redirected to the main left
and right speakers.
The Dolby 3 Stereo creates a panoramic frontal sound field while maintaining the dialog in an on-screen
position. While this mode was designed for Dolby program sources, it may also improve the sound field unity
on non-Dolby programs. However, dialog position and sound image definition may be less accurate with
non-Dolby sources. While this is a recommended mode for Dolby Pro Logic sources when there are no
surround speakers, it is still available when surround speakers have been configured in the basic setup.
Users may enjoy the frontal sound only playback on two channel sources.
The 4-ch Stereo mode makes full use of the main (L, R) and surround (L, R) speakers without adding any
processing or delay. The stereo sound created in the main speakers is identically reproduced in the surround
speakers. This allows full-room stereo playback with enhanced stereo image. A center speaker is not required
for this mode.
The 2-ch Stereo mode only makes use of the main (L, R) speakers, the center or surrounds are turned off and
there is no delay adjustments available.