Linear Acoustic UPMAX2251 User manual

UPMAX 2251
5.1-Channel Surround-Field Synthesizer
User Guide

UPMAX 2251
5.1-Channel Surround-Field Synthesizer
User Guide
Release Date: January, 2004
Software Version: 0.805 and Later
Linear Acoustic Inc.
Phone: [phone]
FAX: [phone]
email: www.LinearAcoustic.com

Warranty Information
DISCLAIMER OF WARRANTIES: Products manufactured by Linear Acoustic Inc. are warranted
against defects in material and workmanship for a period of two (2) years from the date of purchase.
THERE ARE NO OTHER IMPLIED OR EXPRESS WARRANTIES AND NO WAR-
RANTY FOR MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
During the warranty period Linear Acoustic Inc. will repair, or at our discretion replace, components
which prove to be defective, provided the unit is returned, shipped pre-paid to us directly with a return
authorization (RA) number clearly marked on the packaging. Please note, this RA number must be
present or package will be refused and returned to sender.
All requests for repairs MUST include the unit serial number to ensure quick and accurate service.
DEFECTS CAUSED BY UNAUTHORIZED MODIFICATIONS, MISUSE OR ACCI-
DENTS, UNAUTHORIZED CUSTOMER REPAIRS, OR ANY FURTHER DAMAGE
CAUSED BY INADEQUATE PACKAGING FOR SERVICE RETURN ARE NOT COV-
ERED BY THIS WARRANTY.
PLEASE SAVE THE SHIPPING CARTON AND ALL PACKING MATERIALS. FAILURE
TO RETURN UNIT IN ORIGINAL SHIPPING CARTON AND PACKING MATERIALS
WILL RESULT IN A CHARGE FOR NEW SHIPPING MATERIALS.
LIMITATION OF PERIOD OF ACTION ON CONTRACT: No action, regardless of form,
arising out of the transactions under this agreement may be brought by buyer, its successors, agents
and/or assigns, more than three years from date of purchase.
LIMITATION OF LIABILITY: It is understood and agreed that Linear Acoustic’s liability whether
in contract, in tort, under any warranty, in negligence or otherwise shall not exceed the cost of repair
or replacement of the defective components and under no circumstances shall Linear Acoustic be liable
for incidental, special, direct, indirect or consequential damages, or loss of use, revenue or profit even
if Linear Acoustic or its agents have been advised, orally or in writing, of the possibility of such damages.

Linear Acoustic upMAX 2251 User Guide
v
Table of Contents
List of Figures...........................................................................................................................................vi
Chapter 1: Introduction...................................................................................................................5
1.1 Principles of Operation..........................................................................................5
1.2 Signals and Levels...................................................................................................7
1.3 Downmix Compatibility ........................................................................................8
Chapter 2: Connections and Setup.......................................................................................9
2.1 Unpacking and Inspection ....................................................................................9
2.2 Installation ...............................................................................................................9
2.3 Rear Panel ..............................................................................................................10
2.3.1 Connection Ports .................................................................................10
Chapter 3: Applications................................................................................................................13
3.1 Typical Scenarios ..................................................................................................13
3.1.1 Two-Channel Commercials ................................................................14
3.1.2 Sporting Events ....................................................................................15
3.1.3 Music Awards-Type Events................................................................16
3.2 Factory Presets ......................................................................................................17
Chapter 4: Menus..............................................................................................................................19
4.1 Main Menu.............................................................................................................19
4.1.1 Modify Processing Menu ....................................................................19
4.1.2 Setup Menu ...........................................................................................21
4.1.3 System Info ...........................................................................................23
4.1.4 System Options.....................................................................................23
4.1.5 Lock Front Panel..................................................................................24
Chapter 5: Specifications............................................................................................................25

Linear Acoustic upMAX 2251 User Guide
vi
List of Figures
1-1 Audio Block Diagram .........................................................................................................................6
2-1 Rear Panel ...........................................................................................................................................10
3-1 UPMAX 2251 in a commercial upmixing application .................................................................14
3-2 UPMAX 2251 with Dolby DP572 Dolby E Decoder .................................................................15
3-3 UPMAX 2251 in a live sports application .....................................................................................16
3-4 UPMAX 2251 in a music awards-type program ...........................................................................17
4-1 Main Screen showing level meters to the left and menus to the right. .....................................19
4-2 Modify Processing menu; scroll down to access Ext L/R Mix (as shown on right menu) ...20
4-3 Setup menu .........................................................................................................................................21
4-4 Save Preset menu before (left) and after (right) saving ................................................................23

Linear Acoustic upMAX 2251 User Guide
5
Chapter 1: Introduction
The Linear Acoustic UPMAX 2251 produces a 5.1 channel audio signal that is perfect for
eventual transmission via Dolby Digital (also known as AC-3) to all consumers. The unit
accepts a 2-channel input and “upmixes” it to fill as many of the 5.1 output channels as the
user selects. Any input signal from mono to LtRt (Left Total/Right Total) surround en-
coded audio can be applied to the Main Input and an output will be produced that main-
tains consistency with other 5.1 channel programming.
Further, external discrete sources of audio such as announcer or stereo crowd can be ap-
plied to the unit via its Mix Inputs and can be selectively mixed with the audio produced
by the upmixing process. A subwoofer, or LFE channel can also be selectively created
from the Main Input audio or via the discrete LFE Mix Input.
The UPMAX 2251 provides the following features:
• Advanced upmixing algorithm for stable, convincing surround experience.
• Fully compatible with all surround formats including Dolby Digital
• Upmixed surround field is infinitely adjustable in width and depth.
• External inputs allow mixing of discrete and upmixed audio signals.
• Relay bypassed digital inputs for “mission critical” broadcast applications.
• Simple front panel user interface and display.
• Optional HDSDI (SMPTE 292M) input module (available Q1, 2004)
1.1 Principles of Operation
The UPMAX 2251contains two paths for audio signals. The first path contains an upmixer,
a bass extension filter to create the LFE (Low Frequency Effects) or subwoofer channel,
and a simple but powerful set of mix controls to vary each element of the surroundfield.
The second path provides discrete inputs for the Center, LFE, Ls (Left Surround), Rs
(Right Surround), Lf (Left Front) and Rf (Right Front) channels. The upmixed and discrete
outputs are selectively combined to allow for the addition of specific audio elements to the
upmix-derived elements.
Please refer to Figure 1-1. It should be noted that this diagram is a general representation
of signal flow. Please consult the appropriate section of this manual for an accurate de-
scription of actual functionality.

Linear Acoustic upMAX 2251 User Guide Introduction
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Main In
Lt/Rt
Left
Center
Right
UPMIXER
Surround
+
+
+
+
Mix In
Center
Ext Center
Level
Center
Width
Ext LFE
Level
80 Hz
+
Mix In
LFE
Surround
Width
+
+
Ext Ls
Level
Ext Rs
Level
Mix In
Ls
Mix In
Rs
Surround
Depth
Ext Lf
Level
Ext Rf
Level
Mix In
Lf
Mix In
Rf
Main
Out Rs
Main
Out Ls
Main
Out LFE
Main
Out C
Main
Out Rf
Main
Out Lf
Figure 1-1 Audio Block Diagram

Linear Acoustic upMAX 2251 User Guide Introduction
7
Two-channel audio is applied via the Lt/Rt Main Input. The audio is upmixed to produce
Left, Right, Center, and Surround signals. The Left and Right outputs of the upmixer are
passed unmodified to the Left and Right Main Output.
The Center channel output of the upmixer is passed through the Center Width control
which varies the amount of center channel audio present at the Center Main Output versus
how much is summed back into the Left and Right Main Output. A setting of 100% indi-
cates that all of the upmixed Center audio is being fed to the Center Main Output, while
0% indicates that all of the upmixed Center audio is being fed back into the Left and Right
Main Output. The 0% setting is the same as “Phantom Center” mode common on some
decoders.
The Left, Right, and Center outputs of the upmixer are combined then 80Hz low pass fil-
tered and when selected via the LCR Sum To LFE switch are passed via the LCR Sum
Level control to the LFE Main Output.
The Surround output of the upmixer is passed through the Surround Depth control
which varies the amount of surround information present at the Ls/Rs Main Output ver-
sus how much is summed back into the Left and Right Main Output. A setting of 100%
indicates that all of the upmixed Surround audio is being fed to the Ls/Rs Main Output,
while 0% indicates that all of the upmixed Surround audio is being mixed back into the
Left and Right Main Output.
All outputs of the upmixer can also be selectively combined with signals applies to the Mix
Inputs. The Mix Inputs are available for all channels and have Mix Level controls that vary
from off to +6dB. Note that the +6dB range is provided for convenience, but a full-scale
signal applied to these inputs can be increased to clipping, so settings above 0dB should
be used carefully and sparingly.
1.2 Signals and Levels
The Linear Acoustic UPMAX 2251 is calibrated for -20dBFS environments, but will work
fine with other reference levels with the minor caveat that the analog LtRt utility output
(on the LtRt/Aux DB-25 connector) is fixed at -20dBFS=+4dBu.
The sample rate of the UPMAX 2251 is nominally 48kHz, but the unit will run at other sam-
ple rates as determined by the signal applied to the AES REF input. Please note that cur-
rently this causes the test tones to change slightly in frequency, but has no effect on the
program audio.
Below is a list of the inputs and outputs of the UPMAX 2251:
• Lt/Rt Main Input - Main input to upmixer
• Mix Inputs (C/LFE, Ls/Rs, Lf/Rf) - Direct mix inputs to the main output channels

Linear Acoustic upMAX 2251 User Guide Introduction
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• Main Outputs (Lf/Rf, C/LFE, Ls/Rs) - Main audio outputs in SMPTE 320M format
• LtRt Main Output - A utility two-channel downmix of the 5.1 channel program (this
output is also available as an analog signal on the LtRt/Aux connector)
1.3 Downmix Compatibility
Downmixing is the process where the individual channels of a Dolby Digital signal are
combined in order to be reproduced from a given number of channels. For example, a 5.1
channel program must be downmixed to be reproduced from a stereo speaker system and
so the left and right channels are combined with the left and right surround signals and an
attenuated version of the center channel before being output as a stereo signal. This type
of signal is called LoRo (for Left only/Right only).
Downmixing may also produce an LtRt compatible signal by performing a pseudo-sur-
round encode. A 90-degree phase shift is applied to the surround signals in the Dolby Dig-
ital encoder prior to the actual encoding stage so that after downmixing from 5.1 to 2-
channels in the consumer decoder the signal can be heard in surround by the many con-
sumers that only have a matrix surround decoder.
An extremely important design goal of the Linear Acoustic UPMAX 2251 was that the out-
put be downmix compatible. Not only stereo and surround, but also mono- and it had to
sound good in 5.1! A tall order that has been satisfied.
One important thing to remember is that to ensure widest compatibility, the Dolby Digital
encoder must be set to apply a 90-degree phase shift. Luckily, this is the default position
for most of the presets, however please consult the encoders user manual to find the menu
location where this setting can be checked.