miniDSP DDRC-88A User manual

miniDSP Ltd, Hong Kong / www.minidsp.com / Features and specifications subject to change without prior notice 1
DDRC-88A
8-CHANNEL AUDIO PROCESSOR
WITH DIRAC LIVE®TECHNOLOGY
User Manual

miniDSP Ltd, Hong Kong / www.minidsp.com / Features and specifications subject to change without prior notice 2
Revision history
Revision
Description
Date
0.1
First draft
25 November 2014
0.2
Preliminary pre-release version
5 December 2014
0.3
Draft pre-release for comment
20 January 2015
0.4
Second draft pre-release for comment
28 January 2015
1.0
First public release
2 February 2015
1.1
Updated firmware update procedure
20 May 2015
1.2
Update for Mac software
11 July 2015
1.3
Updated Output & Levels tab
16 July 2015

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TABLE OF CONTENTS
Important Information .........................................................................................................................................................5
System Requirements ......................................................................................................................................................5
Disclaimer/Warning .........................................................................................................................................................5
Warranty Terms...............................................................................................................................................................5
FCC Class B Statement......................................................................................................................................................6
CE Mark Statement ..........................................................................................................................................................6
Package Contents.............................................................................................................................................................6
A Note on this Manual .....................................................................................................................................................6
1Product Overview..........................................................................................................................................................9
1.1 Typical system configurations ..............................................................................................................................9
1.2 How Dirac Live® works.......................................................................................................................................10
1.3 DDRC-88A / Dirac Live® configuration steps .......................................................................................................12
2Installation and Setup.................................................................................................................................................. 13
2.1 Hardware connectivity.......................................................................................................................................13
2.1.1 Analog input and output ...........................................................................................................................13
2.1.2 DC Power.................................................................................................................................................. 14
2.1.3 USB........................................................................................................................................................... 14
2.2 Software installation and license activation .......................................................................................................15
2.2.1 Installation ― Windows ............................................................................................................................15
2.2.2 Installation ― Mac OS X ............................................................................................................................16
2.2.3 License activation......................................................................................................................................17
2.2.4 License validation......................................................................................................................................18
3Acoustic Measurement................................................................................................................................................19
3.1 Loudspeaker and microphone positioning..........................................................................................................19
3.2 Preparing for acoustic measurement .................................................................................................................20
3.2.1 Connections and microphone placement................................................................................................... 20
3.2.2 Subwoofer settings ...................................................................................................................................20
3.3 Configuring for measurement............................................................................................................................21
3.3.1 Sound System tab .....................................................................................................................................22
3.3.2 Mic Config tab........................................................................................................................................... 23
3.3.3 Output & Levels tab ..................................................................................................................................24
3.3.4 Custom System configuration....................................................................................................................25
3.4 Running the measurements...............................................................................................................................26
3.4.1 Listening environment...............................................................................................................................27
3.4.2 Executing measurements .......................................................................................................................... 28
3.4.3 Completing the measurements ................................................................................................................. 29
3.4.4 Viewing and redoing measurements..........................................................................................................29
3.5 Saving and loading projects ...............................................................................................................................29
4Filter Design ................................................................................................................................................................30
4.1 Working with graphs .........................................................................................................................................31
4.2 Designing your target curve ...............................................................................................................................33
4.2.1 The Auto Target ........................................................................................................................................33
4.2.2 Editing the target curve............................................................................................................................. 33
4.2.3 Guidelines for target curve design .............................................................................................................34
4.2.4 Saving and loading target curves ...............................................................................................................35

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4.3 Generating correction filters..............................................................................................................................36
4.4 Downloading and managing filter sets ...............................................................................................................37
5Using the DDRC-88A audio processor ..........................................................................................................................38
5.1 Configuring source equipment...........................................................................................................................38
5.1.1 Level trims ................................................................................................................................................38
5.1.2 Subwoofer channel gain............................................................................................................................ 38
5.1.3 Bass management.....................................................................................................................................38
5.1.4 Delays/speaker distance............................................................................................................................38
5.1.5 Room correction and EQ ...........................................................................................................................38
5.1.6 Other processing.......................................................................................................................................39
5.2 Front panel........................................................................................................................................................ 39
5.2.1 Status indicators ....................................................................................................................................... 39
5.2.2 Front panel controls.................................................................................................................................. 39
5.3 Infrared remote control.....................................................................................................................................40
6Gain structure .............................................................................................................................................................41
6.1 Gain structure overview .................................................................................................................................... 41
6.2 Choosing gain structure settings ........................................................................................................................42
6.2.1 To change input sensitivity ........................................................................................................................44
6.2.2 To change output gain............................................................................................................................... 44
6.3 Optimizing gain structure ..................................................................................................................................45
6.3.1 Procedure for optimizing output gain ........................................................................................................45
6.3.2 To increase output gain.............................................................................................................................46
6.3.3 To reduce output gain ............................................................................................................................... 46
6.4 LFE alignment gain.............................................................................................................................................47
6.4.1 The LFE channel and the DDRC-88A........................................................................................................... 47
6.4.2 LFE effect on gain structure .......................................................................................................................48
6.4.3 LFE gain structure problems ...................................................................................................................... 49
6.4.4 Bass management and LFE alignment gain................................................................................................. 49
7Additional Information ................................................................................................................................................50
7.1 The DDRC-88 Utility program.............................................................................................................................50
7.2 Balanced wiring tips...........................................................................................................................................51
7.2.1 Phoenix terminal blocks ............................................................................................................................51
7.2.2 XLR adapters .............................................................................................................................................51
7.2.3 RCA adapters ............................................................................................................................................51
7.3 Specifications .................................................................................................................................................... 52
7.4 Troubleshooting ................................................................................................................................................53
7.5 MCU Firmware update ......................................................................................................................................54
7.5.1 Windows...................................................................................................................................................54
7.5.2 Mac OS X................................................................................................................................................... 55
7.6 Obtaining support .............................................................................................................................................56

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IMPORTANT INFORMATION
Please read the following information before use. In case of any questions, please contact miniDSP via the
support portal at minidsp.desk.com.
SYSTEM REQUIREMENTS
To configure your DDRC-88A audio processor, you will require a Windows or Apple Mac computer with the
following minimum specification:
Windows
Intel Pentium III or later, AMD Athlon XP or later
2 Gigabytes (GB) of RAM or higher
Keyboard and mouse or compatible pointing device
Microsoft• ® Windows® Vista® SP1/Win7/Win8
Two free USB 2.0 ports
Mac OS X
Intel-based Mac with 1 GHz or higher processor clock speed
2 Gigabytes (GB) of RAM or higher
Keyboard and mouse or compatible pointing device
Mac OS X 10.6 or higher
Two free USB 2.0 ports
DISCLAIMER/WARNING
miniDSP cannot be held responsible for any damage that may result from the improper use or incorrect
configuration of this product. Please read this manual carefully to ensure that you fully understand how to
operate and use this product, as incorrect use or use beyond the parameters and ways recommended in this
manual have the potential to cause damage to your audio system.
Please also note that many of the questions we receive at the technical support department are already
answered in this User Manual and in the online application notes on the miniDSP.com website. So please take
the time to carefully read this user manual and the online technical documentation. And if an issue arises with
your unit, please read through the Troubleshooting section first. Thank you for your understanding!
WARRANTY TERMS
miniDSP Ltd warrants this product to be free from defects in materials and workmanship for a period of one
year from the invoice date. Our warranty does not cover failure of the product due to incorrect connection or
installation, improper or undocumented use, unauthorized servicing, modification or alteration of the unit in any
way, or any usage outside of that recommended in this manual. If in doubt, contact miniDSP prior to use.

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FCC CLASS BSTATEMENT
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause undesired
operation.
Warning: This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance
with the instructions, may cause interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful interference to radio
or television reception, which can be determined by turning the equipment off and on, the user is encouraged to
try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Notice: Shielded interface cable must be used in order to comply with emission limits.
Notice: Changes or modification not expressly approved by the party responsible for compliance could void the
user’s authority to operate the equipment.
CE MARK STATEMENT
The DDRC-88A has passed the test performed according to European Standard EN 55022 Class B.
PACKAGE CONTENTS
Your DDRC-88A package includes:
One DDRC-88A audio processor
One universal 12 VDC power supply
One USB cable for computer connectivity (1.5m)
One UMIK-1 calibrated measurement microphone with USB cable
One tripod microphone stand
One full license for Dirac Live Calibration Tool for miniDSP
ANOTE ON THIS MANUAL
This User Manual is designed for reading in both print and on the computer. If printing the manual, please print
double-sided. The embedded page size is 8 ½” x 11”. Printing on A4 paper will result in a slightly reduced size.

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For reading on the computer, we have included hyperlinked cross-references throughout the manual. In
addition, a table of contents is embedded in the PDF file. Displaying this table of contents will make navigation
much easier:
In Adobe Reader on Windows, click on the “bookmarks” icon at the left. The table of contents will appear on
the left and can be unfolded at each level by clicking on the “+” icons.
In Preview on the Mac, click on the View menu and select Table of Contents. The table of contents will
appear on the left and can be unfolded at each level by clicking on the triangle icons.

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1PRODUCT OVERVIEW
Thank you for purchasing a miniDSP DDRC-88A audio processor powered by Dirac Live®, the world’s premier
room correction solution. We are delighted to offer you this software and hardware combination, the fruit of
extensive research and development and years of experience in sound system tuning.
The DDRC-88A is an 8-channel digital audio signal processor (DSP) running the Dirac Live® room correction
algorithm. The onboard floating-point SHARC processor provides time and frequency correction of a 7.1
monitoring, home theater or multichannel audio system. Inputs and outputs are analog, available as both single-
ended signals connected via RCA jacks, and as balanced signals via Phoenix terminal blocks.
The DDRC-88A is a member of the miniDSP Dirac Series of audio processors. Deploying a DDRC-88A will:
Improve imaging and immersion
Improve clarity of music and dialog
Produce a tighter bass
Reduce listening fatigue
Remove resonances and room modes
The DDRC-88A can be used anywhere an 8-channel room correction processor is required, such as in home
theaters, recording and mastering studios, performance venues, places of worship, and so on.
1.1 TYPICAL SYSTEM CONFIGURATIONS
The DDRC-88A is inserted between line-level analog sources and power amplification. In home theater
applications, signal to the DDRC-88A typically comes from an A/V receiver or A/V processor with one or more
source devices, and the amplification is typically a multichannel power amplifier. A source such as a Blu-ray
player with multichannel analog outputs can also be connected directly to the DDRC-88A.

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In studio or sound reinforcement applications, the DDRC-88A is typically connected between a mixing console
and power amplification, as shown below. Individual channels can be set for either full-range or subwoofer
operation.
Computer connectivity is used to perform acoustic measurements and generate digital room correction filters.
Up to four sets of correction filters can be stored on the DDRC-88A processor and recalled from the front panel
or via an infrared remote. Once the processor is fully configured, the computer is no longer needed.
1.2 HOW DIRAC LIVE®WORKS
The miniDSP DDRC-88A audio processor includes Dirac Live®, a premium mixed-phase room correction
technology. This technology is used not only in home stereo and home theater systems but also in cinemas,
recording studios, and luxury cars.
As with any room correction system, Dirac Live® corrects the system’s magnitude response (often referred to
imprecisely as “frequency response”). In contrast to fully automated systems, Dirac Live® corrects the
magnitude response towards a user-adjustable target response. The target response takes account of the
natural frequency range of the loudspeaker system and the normal effects of loudspeaker dispersion on the
measured in-room magnitude response.
In addition, Dirac Live® corrects the system’s impulse response, which reflects how the system responds to a
sharp transient such as a drumbeat. Reflections, diffraction, resonances, misaligned drivers, and so on, all
combine to smear out the transient. An ideal loudspeaker has none of these, so correcting the impulse response
makes the speaker in the room behave much more like that ideal loudspeaker. The impulse response is a critical
factor for accurate sound-staging, clarity and bass reproduction. Dirac Live® employs a sophisticated analysis
algorithm to make the optimal correction across the whole listening area, not just at a single point.