What Is the LCRS Encoder?
The LCRS Encoder VST Plug-in is especially designed for Cubase and
Nuendo. It is an LCRS 4:2 Matrix Encoder. It is not a Dolby
Digital AC-3 Encoder. It encodes 4 channels (Left, Center,
Right, Surround) into two channels (stereo) for playback on Dolby
Pro Logic Style receivers and decoders. If you playback audio encoded
using this encoder on a normal stereo you won't hear the surround
channel but instead you will hear the out of phase information
that may appear to be coming from inside your head. This plug can
be used with the 5.1, 6.0, 6.1 and most other surround formats
found in Nuendo and Cubase. It must have a surround channel. It
is recommended that you switch to the LCRS format otherwise there
will likely be unexpected results. You should note that you can
only pan a single sound at a time. This is more of a limitation
with Dolby Pro Logic Decoders and not the plug-in.
The LCRS Matrix encoder in the PanHandler will convert a stereo input
to mono before processing it. The mono input is then set to a 4-way
(LCRS) pannerwhere it is panned using an extremely fast XY panning
algorithm. The result is 4 audio signals which are labeled: L =
LEFT, C = CENTER, R =RIGHT, and S = SURROUND or
LCRS for short.
Next the 4 audio signals are input into the LCRS Encoder. Where the
4 input signals are "encoded" into to two output signals
(Stereo Wave File). The encoding is done by, I'm going to be as brief
as possible here, summing the Left and Right channels together to create
the Center channel, and the Surround signal is sent to a EQ network
that has been tuned to create the 90 degree phase shift required through
out the 100hz to 7k hz spectrum. The Surround signal is then added
back to the Left Channel and subtracted from the Right Channel.
There are a number of ways in which the surround channel information
is shifted by 90 degrees. The most problematic is doing it without
destroying the quality of the audio by round off and quantization errors.
This is similar to what happens with digital equalization.
What Do I Need To Hear What The Plug-in Does?
You'll need to connect the output of your sound card (Left and Right
Main Outputs) to a Dolby Pro Logic decoder/receiver. These can be found
in any consumer electronics store. Almost all Dolby Digital (AC-3)
receivers are able to decode Dolby Pro Logic. Just connect the sound
card outputs to the stereo input on the decoder/receiver and that's
it.
How to Use the LCRS Encoder
This plug-in is to be used as a Master Plug-in. The encoder
is to be placed in any of the Surround Sound Format's Outputs buss.
At this time only the formats in Cubase have been tested but Nuendo
users shouldn't have any problems with using it in 7.0 Cine, 7.1 Music
and other formats only found in Nuendo 2. You'll notice that there
aren't any knobs. If you've used a Dolby LCRS Encoder you'll note that
there are any knobs either. There's really nothing to adjust. You will
however have to watch the output level. Remember you are encoding 4
channels of audio into 2 channels or even more if you are using the
8.0 Cine format for instance. I chose not to scale back the gain stages
of the plug-in as I think it would be better left to you the engineer.
5.1 does NOT equal 4:2
Because of the limitations of matrix encoding it is best NOT to
use the exact same settings and panning data that you used in the 5.1
mix. LCRS Matrix encoding has a limit of positioning single dominant
sound. This means that only one sound can be panned at a time. Many
time a 5.1 mix doesn't translate at all in LCRS Matrix mode. Don't
be surprise if you find yourself changing pan positions and panning
movements. Alway monitor using a Pro Logic Decoder. I would recommend
at least using a consumer level version.
Mono, Stereo, and/or Surround Sound Compatibility
Determine you final mix playback compatiblity. If want both mono and
Surround Sound capabilities then test your mix on both types of systems.
Always use good shielded cables for all audio input and output connections.
Also, bundle audio cables separately from the AC power cables.
1. Mix in an acoustically well designed room.
2. Make sure you have a diffused Surround/rear sound field.
3. Place Surround speakers up high. Do not tilt down toward mixing
position.
4. Do not de-correlate/pitch-shift surround channel.
Because Surround Sound Decoder's are designed to decode/pan a single
sound source (the dominant signal), you should be careful not to confuse
the decoder. Some Surround Sound decoders may just give and shutdown
if it gets confused, though this has never happened in our testing
of the PanHandler. If you are panning two or more sounds at the same
time, then listen for 'the wandering image', where the sound just doesn't
behave as you panned it.
Generally speaking most sounds are expected to come predominantly
from the screen direction, since that is where we see the action. Sounds
which are assigned to the surround track usually are not associated
with specific source locations. For example you might see a lightning
strike on screen, but we'll hear the thunder, rain, and wind all around
(in the surround speakers).
Also check to make sure that the sounds overall volume is not to high
then lower it. Sometimes saturation can effect the phase relationship
between the Left and Right mains. This may sound like the moves really
fast and then comes back to it's normal position.
Setting up your system
It is recommended that you test your surround sound setup using a
Surround Sound encoded video for example. Select one which you like
and use it to fine tune your surround system. Adjust the Center, and
Surround levels, EQ., and the Surround's delay time on your receiver.
You should setup your surround receiver/decoder by following the
instructions which came with your system. If you are not sure on
how to setup you system, then find someone who does. It is best to
place the surround sound receiver close enough to access the volume
control and eq. controls. Plug your sound card's LINE OUT, NOT the
HEADPHONE OUT and NOT the SPEAKER OUT, into the most appropriate
analog or spdif digital input of the surround sound receiver.
Where Should The Center Speaker Go ?
If the center monitor is going to be placed on top of the video screen
then make sure it's magnetically shielded, otherwise you could ruin
your monitor. Another arrangement is to move the computer off to
the left or right with the center speaker in the middle. You can
also just forget using a center speaker and switch your receiver
to Phantom mode. In this mode the center channel information
is equally sent to both the left and the right channels.
The Front Speakers - Left, Center, and Right
The Front left and right speakers carry primarily music and sound effects
while the center speaker carries much of the dialogue as well as
music and effects. Ideally, all three will be the same model for
best acoustic matching. Use a magnetically shielded speaker for the
center speaker if it is to be positioned near a video monitor.
The Surround Speakers
At least two surround speakers should be used. Even though the surround
channels have a limited frequency response, from 100 Hz to 7 kHz,
they should have a wide dispersion. If possible, a smaller speaker
of the same type used for the center, left and right should be used.
This will assure sonic matching.. Generally, good quality two-way
bookshelf speakers are sufficient for surround channel use.
Positioning Requirements
The center speaker needs to be at the same height as the left/right
pair for best imaging. It is recommend that the surround speakers
be located 5 feet (1.5 meters) closer the listener than the front
speakers. This may be impractical in certain situations, especially
if your computer dictates how you setup your system. Surround speakers
are typically located two or three feet above ear level, and should
not be aimed directly at the mixing position. The goal here is for
an evenly dispersed soundfield, with no prominent hot spots or in
the head images. While the surround speakers should be in-phase with
each other, their absolute polarity has no relevance to the front
channels since the decoder introduces time delay into the surround
channel. Also check that the polarity (phasing) is correct in all
three front speakers so that panned effects create proper phantom
images between the center/side speaker pairs.
Surround Sound Time Delay
When choosing a delay time for your decoder the following formula will
help you chose the required delay time setting:
T=Nd + Df - Ds
Where:
T is the delay setting
Nd is the net delay time in milliseconds
Dfis the distance in feet from the listener to the nearest front
speaker
Ds is the distance in feet from the listener to the nearest
surround speaker.
NOTE: Some decoders only increment in 5 milli-second intervals,
just choose the closest one.
Surround Decoder Modes
Most Surround decoders have a number of decoder settings. The 'PHANTOM'
mode sends the center channels output equally into the left and right
speakers. This eliminates any need for a center speaker, though the
frontal imaging is not as precise. The 'NORMAL' setting generally
means that the center speaker's low frequencies are fed into the
left and right channels. If your are using a satellite/subwoofer
setup then use the 'NORMAL' setting. If you are using full-range
speakers for the left, center, and right speakers then use the 'WIDE'
setting. The 'WIDE' setting sends the full range (20->20k hz)
signal to the center speaker. The 'DOLBY 3' setting generally means
that the surround signal is sent equally into the left and right
speakers. You should select a mode which accommodates your system.
DSP - Reverb and Room Simulation Modes
Some Surround Receivers/decoders have room simulation modes, ie: reverb,
and early reflections. Though it might be interesting to hear what
your surround encoded material sounds like using these modes, it
is best to turn them OFF. These DSP modes usally just add noise,
and besides the listener of your final mix may not have or even like
these modes.
Matching Impedance and Sensitivity
You may also want to see if your Surround decoder's input impedance
and sensitivity matches your sound cards output. An exact match is
not critical but it should be close. The main importance of this
is in the surround decoder's 'B' type noise reduction circuit and
the gain riding for the front left, center, and right channels. If
there is a large mismatch between your card and decoder then the
decoder will not response correctly.
DISCLAIMER
All the usual disclaimers apply. I do not guarantee that this software
is error free. Nor do I guarantee that it will work as described on
all systems. I do no accept any liability for loss caused by the use
of this software.
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